Product Guides
Quick Guide to Choosing the Right LOCTITE® Product
LOCTITE® offers a variety of adhesives tailored for specific applications. Here's a quick rundown to help you choose:
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Loctite 222: Purple Low-Strength Threadlocker Guide
Purple low-strength threadlocker for fasteners under 6mm. Cure times, breakaway torque, 222 vs 243, Activator 7471 for inactive metals, and the 222MS Mil-Spec variant — explained.
Read moreloctite-577-guide
Threaded pipe joints fail for two reasons: the wrong sealant or no sealant at all. PTFE tape shreds, bunches, and leaves installer skill as the critical variable. Old pipe dope shrinks over time. Loctite 577 eliminates both problems — it's an anaerobic thread sealant that cures into a solid polymer seal inside the thread void, filling gaps completely without shredding, creeping, or hardening. This guide covers everything you need to apply Loctite 577 correctly: what it is, how it cures, cure times, the full Loctite thread sealant comparison table, fluid and media compatibility, when you need an activator, and the mistakes that cause failures. Whether you're sealing compressed air fittings, hydraulic lines, water pipe, or gas — this is the reference guide. Loctite Thread Sealant Comparison Guide — Quick Reference Henkel makes five standard thread sealants in their Loctite range, each targeting a specific thread type, application, or substrate. Choosing the wrong product for the application is the most common purchasing mistake. Product Strength Viscosity Best Application Thread Types Temp Range Stainless Steel AIMS Product Loctite 542 Medium Low (liquid) Fine metric and BSP hydraulic / pneumatic instrument connections — M6 to M36 Fine metric, small BSP -55°C to +150°C Slow without activator View 542 Loctite 565 Low–Medium Paste General-purpose all-metal pipe fittings; low-pressure water, air, general plumbing BSPT, NPT, metric parallel -55°C to +150°C Acceptable View 565 Loctite 577 Medium Thixotropic paste General-purpose metal fittings; compressed air, hydraulics, water, gas, high-pressure lines up to 2" BSP / 400 bar BSPT, NPT, BSPP, metric -55°C to +150°C Good (activator for fastest cure) View 577 Loctite 567 Low–Medium Low (liquid) Stainless steel, copper, and passive metal fittings; where lower strength and easier disassembly are preferred All pipe thread types -55°C to +200°C Excellent (engineered for SS) View 567 Loctite 569 High Paste High-strength hydraulic systems; permanent or semi-permanent sealing; fittings that must not back off under extreme pressure or vibration BSPT, NPT, metric parallel -55°C to +150°C Slow without activator View 569 What Is a Thread Sealant? A thread sealant fills the spiral gap between mating threaded pipe connections to prevent fluid or gas leaks. Unlike a threadlocker — which locks bolts and fasteners against vibration loosening — a thread sealant is specifically engineered for pipe and fitting threads, where the goal is pressure-tight sealing rather than torque retention. Loctite 577 anaerobic sealant is one option for BSP thread sealing — for flat-face fitting joints and reusable hydraulic connections, the mechanical alternative is the Dowty washer (bonded seal). See the Dowty washer and bonded seal guide for when to use each. The two words look similar enough to cause real purchasing mistakes. A threadlocker (Loctite 243, 270, 277) works on cylindrical bolt threads and cures to high shear strength. A thread sealant (Loctite 577, 567, 542) works on tapered and parallel pipe threads and cures to fill the helical void, blocking fluid passage. The products are not interchangeable — using a threadlocker on pipe threads gives poor sealing; using a thread sealant on bolts gives inadequate locking strength. Anaerobic thread sealants like Loctite 577 cure when two conditions are met: contact with metal ions (the catalyst) and exclusion of oxygen (the inhibitor is removed). Outside the joint, exposed to air, they remain liquid indefinitely — which is why excess sealant on the outside of a fitting stays wet long after the joint has cured internally. This is by design, not a failure. See the FAQ section for a full explanation of this common point of confusion. For a broader overview of thread locking and sealing products, see our Thread Locking & Sealing Guide and Loctite Threadlocker Selection Guide. What Is Loctite 577? Loctite 577 is a single-component, medium-strength, thixotropic anaerobic thread sealant designed for general-purpose sealing of metal pipe threads and fittings. Developed by Henkel, it is the direct replacement for traditional methods including PTFE tape, hemp/jointing compound, and liquid pipe dopes. Its thixotropic paste consistency is a deliberate engineering choice: it flows under the shear force of thread engagement but holds its position on vertical threads before assembly, preventing drip and run-off. This makes it far easier to control than thin liquid sealants on large-diameter or overhead fittings. Loctite 577 is approved for industrial and process water systems, natural gas and LPG, hydraulic fluid, diesel, compressed air, and notably for hydrogen gas up to 100% (KIWA GASTEC QA AR 214), making it one of the few commercially available thread sealants cleared for hydrogen fuel systems. Note that for potable (drinking) water connections, use Loctite 55 sealing cord — it carries NSF 61 certification; the anaerobic liquid sealants including 577 do not. Property Value Type Anaerobic, single component Colour Cream / off-white Viscosity Thixotropic paste (medium-high) Strength Medium — disassemble with hand tools Operating temperature -55°C to +150°C (short-term peak 200°C) Max thread size Up to 2-inch BSP Max gap fill 0.25–0.4 mm depending on substrate Max pressure (sealed) Up to 400 bar Fixture time (steel, 22°C) 10–60 minutes Full cure time 24 hours at 22°C Potable / drinking water Not NSF 61 certified — use Loctite 55 for drinking water Gas approval BS 6956 Type B; KIWA GASTEC QA AR 214 (incl. H₂) Sizes available 50 ml, 250 ml Thread Sealant vs PTFE Tape: Which Should You Use? PTFE tape (also called Teflon tape or plumber's tape) has been the default for pipe thread sealing for decades — but its dominance rests on familiarity and low cost, not technical superiority. For professional and industrial applications, anaerobic thread sealants like Loctite 577 address every key weakness of PTFE tape. Factor Loctite 577 PTFE Tape Shredding / contamination risk None — cures solid inside joint Can shred into valves, filters, pumps Hydraulic systems Approved ✓ Not recommended — fragments in fluid Vibration resistance Excellent — cured polymer resists loosening Poor — thread can back off under vibration Gap filling Up to 0.4 mm — fills worn or oversize threads Minimal — tape deforms but does not fill Application consistency High — same result every time Variable — depends on wrap technique and layers Minor oil contamination tolerance High — tolerates light surface contamination Low — contamination compromises wrap adhesion Disassembly Hand tools for medium strength Easy — unwind and re-tape Potable / drinking water Not NSF 61 certified — use Loctite 55 Loctite 55 cord is NSF 61 certified for drinking water Cost per joint Higher Lower Learning curve Low — apply to male thread, assemble Low — but more variable outcomes When PTFE tape is the right call: low-pressure domestic water fittings where cost matters most, or when sealing plastic-to-metal thread connections (anaerobic sealants are not suitable for most plastic threads — see Common Mistakes below). For everything else — hydraulic systems, compressed air, gas lines, or any application where contamination of the downstream fluid is unacceptable — Loctite 577 is the better technical choice. How to Apply Loctite 577 Correct application takes less than two minutes per fitting. The most common failures come from skipping the cleaning step or over-applying. Follow these six steps. Step 1 — Clean and degrease. Remove all oil, grease, old sealant, and loose particles from both male and female threads. Use Loctite SF 7070 Cleaner & Degreaser or another fast-evaporating industrial degreaser. Allow to dry fully — wet solvent residue will slow cure. This step is the one most often skipped, and the one most responsible for slow or failed cures. Step 2 — Inspect threads. Check threads for damage, burrs, or excessive wear. Loctite 577 will fill gaps up to 0.4 mm, but damaged threads that prevent proper assembly will reduce sealing performance. Re-cut or replace fittings with significant damage. Step 3 — Apply to male thread. Apply a 360° bead of Loctite 577 to the male thread, starting from the second or third thread (leaving the leading thread clear to prevent contamination of the downstream fluid). For coarser or larger threads, also apply to the female thread to ensure full void coverage. Force the material into the thread form — don't just coat the surface. Step 4 — Assemble immediately. Engage and tighten the fitting using hand or wrench torque in accordance with the fitting manufacturer's specification. Loctite 577 begins curing on contact with metal, so assemble promptly. You have a working time of approximately one hour from application to make any positional adjustments — after that the cured sealant begins to resist repositioning. Step 5 — Wipe excess. Clean any excess product from the outside of the fitting before cure. Excess sealant exposed to air will remain liquid indefinitely (this is normal — see the FAQs). Removing it now is easier than mechanical removal later. Step 6 — Wait before pressure testing. Allow the joint to reach fixture strength before applying line pressure. On steel at 22°C this takes 10–60 minutes. For full chemical resistance and maximum pressure rating, allow 24 hours before full service loading. In cold conditions (below 10°C) or on passive metals, use Loctite SF 7649 activator — see the primer section below. Cure Times Loctite 577 is an anaerobic product — cure rate depends on temperature, substrate reactivity, and gap size. The table below covers typical conditions on carbon steel at 22°C. Brass cures noticeably faster; stainless steel and aluminium slower. Stage Time (Steel, 22°C) What It Means Initial handling strength 10–60 minutes Joint holds position; not ready for pressure Low-pressure service 1–3 hours Suitable for static, low-pressure testing Full cure / full service 24 hours Full chemical resistance; rated pressure; full torque Condition Effect on Cure Solution Below 10°C Significantly slower — may take 48–72 hrs for full cure Use SF 7649 activator or bring assembly to room temp Brass / copper threads Faster — brass is highly reactive, near-instant initial seal No change needed Stainless steel Slower — passive oxide layer reduces metal ion activity Apply SF 7649 activator to female thread before assembly Aluminium / zinc / cadmium plating Slower — passive surfaces Apply SF 7649 activator Large gap (>0.25 mm) Slower on outer surface of gap Apply to both male and female threads; use activator Heavy contamination Can prevent cure or cause weak bond Degrease thoroughly with SF 7070 before application Important note on exposed excess: Sealant squeezed outside the joint and exposed to air will never cure — it will remain liquid or tacky indefinitely. This is the correct behaviour of an anaerobic product, not a sign of product failure. The joint itself, where sealant is trapped between metal threads with no air, cures normally. Loctite Thread Sealant Comparison Guide Henkel makes five standard thread sealants in their Loctite range, each targeting a specific thread type, application, or substrate. Choosing the wrong product for the application is the most common purchasing mistake. The table below compares all five by the criteria that matter in practice. Product Strength Viscosity Best Application Thread Types Temp Range Stainless Steel AIMS Product Loctite 542 Medium Low (liquid) Fine metric and BSP hydraulic / pneumatic instrument connections — M6 to M36 Fine metric, small BSP -55°C to +150°C Slow without activator View 542 Loctite 565 Low–Medium Paste General-purpose all-metal pipe fittings; low-pressure water, air, general plumbing BSPT, NPT, metric parallel -55°C to +150°C Acceptable View 565 Loctite 577 Medium Thixotropic paste General-purpose metal fittings; compressed air, hydraulics, water, gas, high-pressure lines up to 2" BSP / 400 bar BSPT, NPT, BSPP, metric -55°C to +150°C Good (activator for fastest cure) View 577 Loctite 567 Low–Medium Low (liquid) Stainless steel, copper, and passive metal fittings; where lower strength and easier disassembly are preferred All pipe thread types -55°C to +200°C Excellent (engineered for SS) View 567 Loctite 569 High Paste High-strength hydraulic systems; permanent or semi-permanent sealing; fittings that must not back off under extreme pressure or vibration BSPT, NPT, metric parallel -55°C to +150°C Slow without activator View 569 The most important distinction: if you're sealing bolt threads rather than pipe threads, you need a threadlocker (Loctite 243, 270, or similar), not a thread sealant. These are fundamentally different product types. See our Loctite Threadlocker Guide for bolt and fastener applications. 577 vs 567 — the question we get most: 577 is the higher-viscosity general workhorse for coarser BSP and NPT threads across all common industrial applications. 567 is lower viscosity, flows into finer thread forms, and is purpose-built for stainless steel and other passive metals where its PST (Pipeline Sealant Technology) chemistry provides faster, more reliable cure without an activator. If your fittings are predominantly stainless or copper, 567 is the better technical choice. If you're working across mixed metals in a general industrial or workshop environment, 577 covers more situations with one product. Fluid and Media Compatibility Loctite 577 has broad chemical resistance once cured, but there are application types it is not suited to. Check your specific fluid or gas against the table below before specifying. Fluid / Media Loctite 577 Compatible? Notes Compressed air ✓ Yes Standard application; widely used in workshop and industrial systems Water — industrial / process ✓ Yes Industrial and process water systems; not NSF 61 certified — use Loctite 55 cord for potable/drinking water lines Steam (below 120°C) ✓ Yes Within -55°C to +150°C rating; verify system temp Natural gas / LPG ✓ Yes BS 6956 Type B approved Hydrogen gas (up to 100%) ✓ Yes KIWA GASTEC QA AR 214 — one of few sealants cleared for H₂ systems Diesel fuel ✓ Yes Good fuel resistance once fully cured Petrol / gasoline ✓ Yes Fuel resistant once cured; allow 24-hour full cure before exposure Hydraulic oil (mineral) ✓ Yes Standard use; preferred over PTFE tape for hydraulic BSP threads Synthetic hydraulic fluid ✓ Yes Check specific fluid data sheet for extreme chemistries Coolant / antifreeze ✓ Yes Suitable for cooling system fittings Refrigerant (R410A, R32, R134a) ✗ No Not rated for refrigerants — use Loctite 554 or approved refrigerant-grade sealant Strong acids / oxidising agents ✗ No Anaerobic polymer is not acid-resistant; use PTFE or specialist chemical sealant Ketones (MEK, acetone) ✗ No Solvents attack cured polymer Chlorinated solvents ✗ No Not compatible — may cause seal degradation Passive Metals and When You Need an Activator Anaerobic thread sealants cure through a reaction catalysed by metal ions. Active metals — iron, steel, copper, brass — release ions freely and drive a fast, complete cure. Passive metals — stainless steel, aluminium, zinc, cadmium plating, titanium — have oxide layers that slow or inhibit the metal ion release, resulting in slow or incomplete cure, particularly on larger gap sizes. Loctite 577 is formulated to tolerate stainless steel without an activator for smaller gaps (under 0.25 mm) and at room temperature. But in practice, for reliable, predictable cure on stainless, aluminium, or plated fittings — particularly in cold conditions or where the fitting may be under pressure before 24 hours — using Loctite SF 7649 activator is the correct procedure. Apply SF 7649 to the female thread as a thin film and allow 1–2 minutes for the solvent carrier to evaporate before applying Loctite 577 to the male thread and assembling. The activator provides the metal ion catalyst externally, accelerating cure to near the same rate as on active steel. It also overcomes cure issues in cold environments below 10°C. Do not apply activator directly over the wet sealant — it is a pre-treatment for the mating surface, not a post-cure accelerant. Common Mistakes to Avoid Most Loctite 577 failures trace back to one of these six errors: 1. Skipping the cleaning step. The most common cause of slow or failed cure. Even light oil film on threads from machining or handling reduces metal ion availability. Clean with SF 7070 or a solvent cleaner and allow to fully dry before applying sealant. Wet threads or residual solvent both impair cure. 2. Using on plastic or non-metallic fittings. Anaerobic sealants are formulated for metal-to-metal thread engagement. On plastic threads — nylon, PVC, PVDF, polypropylene — Loctite 577 will not cure reliably (no metal ion catalyst) and can cause stress cracking in certain thermoplastics. For plastic-to-plastic or plastic-to-metal threads, use PTFE tape or a purpose-built plastic pipe sealant such as Loctite 5331. 3. Applying too much product. More is not better. A thin, continuous 360° bead on the male thread is all that is needed. Excess product is squeezed outside the joint on assembly and remains liquid permanently (anaerobic — exposed to air). It doesn't improve sealing and creates a mess. The actual seal is formed by the product trapped inside the thread void. 4. Pressurising before adequate cure. Applying full line pressure before the sealant has reached fixture strength forces uncured product out of the joint and can wash away the seal. On steel at 22°C, wait at least one hour before low-pressure testing and 24 hours before full-rated pressure. In cold conditions, wait longer or use activator. 5. Ignoring passive metal cure speed. Fitting stainless steel, aluminium, or plated fittings and expecting the same cure profile as carbon steel fittings is a setup for callbacks. On stainless without activator, fixture time can be several hours and full cure can take 48–72 hours. Use SF 7649 activator on passive metals as standard practice, not as an afterthought. 6. Combining with PTFE tape. A common field workaround — "belt and braces" thinking — that actually undermines both products. PTFE tape prevents the metal-to-metal contact needed for anaerobic cure. Either use 577 or use tape. Never both on the same fitting. Removing Loctite 577 Loctite 577's medium-strength cure means disassembly is straightforward in most cases. Unlike high-strength products like Loctite 569, you generally don't need heat to break the joint. Before full cure (within 24 hours): Disassemble with standard hand tools or a wrench. The partially cured polymer breaks cleanly. Clean threads with a solvent or wire brush before re-sealing. After full cure (24+ hours): Apply a standard pipe wrench or adjustable spanner. Medium-strength cured product will break free with normal torque. For stubborn joints or in situations where you need to avoid thread damage (e.g., brass or aluminium fittings), apply localised heat with a heat gun or small propane torch to 150–200°C. This softens the polymer and allows disassembly with minimal torque. Cleaning after removal: Wire brush, nylon brush, or a clean rag with solvent (acetone or SF 7070) removes residual product from threads. Allow to dry before applying fresh sealant. Do not re-use degraded or contaminated sealant from the old joint — apply fresh product. Loctite 577 is an anaerobic pipe thread sealant — one of several adhesive product types used in Australian industrial maintenance. For a complete guide to all industrial adhesive types including anaerobic threadlockers, retaining compounds, epoxy, contact adhesive, and RTV silicone, see the Industrial Adhesive Types Guide. Frequently Asked Questions What is Loctite 577 used for? Loctite 577 is used for sealing metal pipe threads and fittings against leaks in compressed air, hydraulic, water, gas, diesel, and steam systems. It replaces PTFE tape and traditional pipe dope by curing into a solid polymer seal inside the thread void. It is not a threadlocker and should not be used on bolt or fastener threads. How long does Loctite 577 take to cure? On carbon steel at 22°C: initial handling strength in 10–60 minutes, suitable for low-pressure testing after 1–3 hours, full cure and full rated pressure after 24 hours. Brass cures faster; stainless steel and aluminium slower. In cold conditions (below 10°C) or on passive metals, use Loctite SF 7649 activator to achieve practical cure times. What is the difference between Loctite 577 and 567? 577 is a thixotropic paste suited to coarser BSP and NPT threads in general industrial applications across all common metals. It is the standard workhorse for compressed air, water, hydraulic, and gas fittings. 567 is a lower-viscosity liquid that wicks into finer thread forms and is purpose-built for stainless steel and passive metals, where its PST chemistry delivers reliable cure without requiring an activator. If your installation is predominantly stainless steel or copper fittings, 567 is the better technical choice. For mixed-metal environments with larger threads, 577 covers more ground with one product. Is Loctite 577 suitable for fuel, gas, and water lines? Yes for industrial applications. Loctite 577 is approved for natural gas and LPG (BS 6956 Type B), hydrogen gas up to 100% (KIWA GASTEC QA AR 214), diesel, petrol, hydraulic oil, and industrial water and process water systems. It is not NSF 61 certified — for potable (drinking) water connections, use Loctite 55 sealing cord. It is also not suitable for refrigerants (R410A, R32, R134a) — use Loctite 554 for refrigerant line fittings. Is Loctite 577 removable? Yes. Loctite 577 is medium strength and designed for disassembly with standard hand tools in most cases. For very tight or long-cure joints, applying localised heat (150–200°C) softens the polymer and makes disassembly straightforward. This is distinct from high-strength thread sealants like Loctite 569, which require more effort to remove. What is the difference between a thread sealant and a threadlocker? A thread sealant (Loctite 577, 567, 542) seals pipe and fitting threads against fluid or gas leakage. A threadlocker (Loctite 243, 270, 277) locks bolts and fasteners against vibration-induced loosening. The chemistry is similar but the gap fill, strength, and application are different. Using the wrong type for the wrong application gives poor results — do not substitute one for the other. Is Loctite 577 better than PTFE tape? For most industrial, hydraulic, and professional applications: yes. Loctite 577 fills thread gaps completely, eliminates shredding contamination risk, tolerates minor oil contamination, and provides consistent results regardless of installer technique. PTFE tape is banned from hydraulic systems precisely because fragments cause damage to valves and pumps. For simple domestic water fittings where cost is the primary concern, PTFE tape remains practical. For anything involving hydraulic fluid, gas, or high pressure, use Loctite 577. Can Loctite 577 be used on stainless steel? Yes, with some qualification. Loctite 577 will cure on stainless steel, but more slowly than on carbon steel, because stainless steel's passive oxide layer reduces metal ion availability for the anaerobic cure reaction. For smaller gaps and normal temperatures, it cures adequately without an activator within 24 hours. For reliable, fast cure on stainless — particularly in cold conditions or where early pressure loading is required — apply Loctite SF 7649 activator to the female thread before assembly. Can Loctite 577 be used on plastic fittings? No. Anaerobic thread sealants require metal-to-metal thread contact to cure — plastic provides no metal ion catalyst. Loctite 577 will not cure reliably on plastic threads and can cause stress cracking in certain thermoplastics (particularly PVC, CPVC, and ABS). For plastic-to-plastic or plastic-to-metal connections, use PTFE tape or Loctite 5331 Plastic Pipe Sealant, which is specifically formulated for plastic thread systems. Why is excess Loctite 577 still wet after 24 hours? This is normal. Loctite 577 is an anaerobic product — it only cures when oxygen is excluded. Inside the joint, where sealant is trapped between metal thread surfaces with no air contact, curing proceeds normally. Outside the joint, exposed to air, the sealant remains liquid indefinitely. The wet exterior is not a sign of failure — the joint itself is cured. Wipe off the excess before it hardens into a difficult-to-remove skin. When do I need an activator with Loctite 577? Use Loctite SF 7649 activator when working with passive metals (stainless steel, aluminium, zinc, plated surfaces), in cold conditions below 10°C, when you need full cure in less than 24 hours, or when gap sizes exceed 0.25 mm on passive surfaces. Apply a thin film of activator to the female thread, allow the solvent carrier to evaporate for 1–2 minutes, then apply Loctite 577 to the male thread as normal and assemble. Do not apply activator over wet sealant. What Loctite thread sealant should I use for fine hydraulic threads? For fine metric or BSP hydraulic and pneumatic instrument connections (M6–M36 or small-bore hydraulic block fittings), use Loctite 542 — its low viscosity wicks cleanly into fine thread forms without over-filling. Loctite 577 is higher viscosity and better suited to coarser BSP and NPT threads up to 2-inch diameter. For general hydraulic fittings (3/8" BSP and above), 577 is the standard choice. Shop Loctite Thread Sealants AIMS Industrial stocks the full Loctite anaerobic thread sealant range in 50 ml and 250 ml sizes, including 542, 565, 567, 577, and 569 — with same-day despatch from our Milperra warehouse. If you're replacing PTFE tape or jointing compound across a facility, the Loctite thread sealant range covers every thread type, pressure rating, and substrate combination you'll encounter. Need help selecting the right product for your system? Our technical team at AIMS Industrial can advise on product selection for specific fluids, pressures, and substrate combinations — contact us directly or visit our Loctite Product Guide for further guidance. For related sealing applications, see our guides on RTV Silicone & Gasket Maker selection, Loctite 401 Instant Adhesive, and our Butterfly Valve Guide — Loctite 577 is the recommended thread sealant for BSP port connections on butterfly valve bodies and actuator assemblies. People Also Ask — Loctite 577 Thread Sealant Q: What is Loctite 577 used for? As this guide explains, Loctite 577 is an anaerobic thread sealant for metal pipe and fitting assemblies — including NPT, BSPT, and parallel thread fittings in hydraulic, pneumatic, water, and oil systems. It seals the thread form itself rather than spanning the bore, providing a leak-free joint that resists vibration loosening and can be disassembled with standard tools when required. Q: What is the difference between Loctite 577 and PTFE tape? Covered in this guide: PTFE tape is a mechanical gap-filler that can creep, extrude under pressure, and leave fragments in the system. Loctite 577 is a liquid that wicks into the thread helix, cures anaerobically in the absence of air, and bonds the joint chemically. It provides superior vibration resistance with no loose fragments. PTFE tape remains common for plumbing; Loctite 577 is preferred for precision industrial and hydraulic/pneumatic systems. Q: Is Loctite 577 suitable for gas pipe fittings? This guide addresses media compatibility directly: Loctite 577 is suitable for many gas applications, but always verify the product is appropriate for the specific gas, operating pressure, fitting material, and any applicable regulatory requirements for the installation. Some gas systems in Australia require products specifically approved for gas service. Refer to the current product TDS and relevant codes before use. Q: What surfaces is Loctite 577 compatible with? As covered in this guide, Loctite 577 performs on most active metals including steel, stainless steel, copper, and brass. On passive metals such as zinc, aluminium, and some stainless alloys, cure may be slower and an activator may be needed. The guide includes a full compatibility and activator reference for common substrate combinations encountered in industrial maintenance. Q: How does Loctite 577 compare to other Loctite thread sealants? This guide includes a full comparison table. Loctite 577 is a medium-strength sealant suited to general pipe assemblies. Loctite 567 is lower viscosity, designed for fine-pitch threads. Loctite 55 is a thread sealant cord rather than a liquid product. Loctite 572 is a slow-setting alternative with higher temperature resistance. Product selection depends on thread pitch, substrate, operating temperature, and whether disassembly will be required. For SmartWasher and benchtop parts washers, see the AIMS parts washer range. See AIMS's full high pressure fittings range — trade pricing and Australia-wide despatch.
Read moreRTV Silicone Gasket Maker Guide: Application, Cure Time and Selecting the Right Product
Pick up a bottle of RTV silicone gasket maker and the shelf next to it has five more — black, red, grey, blue, copper. Most people grab the one they.
Read moreloctite-401-guide
What Is Loctite 401? Loctite 401 is a general-purpose cyanoacrylate ("super glue") industrial instant adhesive made by Henkel. It bonds metals, plastics, rubber, ceramics, leather, paper and most porous and non-porous materials, and develops handling strength in seconds. It's the most widely-used grade in the Loctite cyanoacrylate range and the default starting point for instant adhesive selection across maintenance, assembly and production work. What is cyanoacrylate? Cyanoacrylate (CA) is the chemistry family behind every "super glue" or "instant adhesive". It cures rapidly by reacting with trace surface moisture rather than air drying or heat curing. Loctite 401 is one cyanoacrylate grade among many — others in the Loctite range are formulated for specific substrates, gap sizes, flexibility, temperature resistance or impact resistance. What is Loctite 401 best for? Close-fitting joints in production assembly, maintenance bonding of small parts, prototyping, and any application where you need a fast, clean, high-strength bond on a small area. It's not the right grade for flexible joints, large gaps, very rough surfaces or high-temperature/high-impact service — Henkel publishes dedicated grades for those cases. Loctite 401 is an industrial instant adhesive used across manufacturing, maintenance, and assembly work to bond metals, plastics, rubber, ceramics, and porous materials — fast. If you’ve ever reached for a bottle of super glue and wondered whether this is the same thing, the short answer is: same chemistry, different product. Here’s everything you need to select, apply, and store it correctly. Quick answer — Loctite 401 essentials What it is: Loctite 401 is an industrial-grade ethyl cyanoacrylate (CA) instant adhesive — same chemistry family as consumer super glue but engineered for industrial substrates and consistency. Cure time: Fixture in 5-20 seconds depending on substrate. Full cure 24 hours. Faster on porous materials (rubber, leather, wood), slower on glass and acidic surfaces. What it bonds: Metals, most plastics, rubber, ceramics, porous materials. Doesn't bond well: PE, PP, PTFE, silicone (use Loctite primer) · oily/wet surfaces · large gaps over 0.1mm. Loctite 401 vs 406: 401 = general purpose, medium viscosity. 406 = specifically for rubber/plastic, low viscosity. 414 = metal-bonding optimised. Loctite 401 is an industrial-grade ethyl cyanoacrylate (CA) instant adhesive made by Henkel as part of the Prism range. It bonds metals, rigid plastics, rubber, ceramics, and porous materials in 3 to 10 seconds, with full cure in 24 hours. Loctite 401 is the general-purpose product in the range — surface-insensitive (it bonds reliably on chromated and acidic metal surfaces where standard super glues fail), medium viscosity, and the most commonly stocked Loctite instant adhesive in Australian workshops. Loctite 401 — Quick Reference Property Value Chemistry Ethyl cyanoacrylate (CA / super glue family) Viscosity 100–120 mPa·s (medium) Fixture time 3–10 seconds (substrate dependent) Full cure 24 hours at 22°C Operating temperature −55°C to +80°C Shear strength on steel ~14 N/mm² Max bond gap <0.1 mm (not a gap filler) Bonds well Metals, rigid plastics, rubber, ceramics, porous materials Does NOT bond PE, PP, PTFE, silicone (use SF 770 primer) Shelf life 12 months unopened, 30 days after opening What Is Loctite 401? Loctite 401 is an ethyl cyanoacrylate (ECA) instant adhesive, part of Henkel’s industrial Prism range. Like all cyanoacrylates, it cures on contact with surface moisture — no mixing, no heat, no UV light required. What sets 401 apart from consumer super glues is its surface-insensitive formulation: it performs reliably on acidic or chemically treated surfaces such as chromated metals and galvanised steel, where standard cyanoacrylates often fail to achieve full strength. The “Prism” designation refers to Henkel’s industrial-grade instant adhesive line, which includes 401, 406, 408, 454, 480, and 495 among others — each optimised for specific substrate and application requirements. Loctite 401 is the general-purpose product in that range. Loctite 401 is not a threadlocker. If you need to secure a bolt or fitting against loosening, see our Loctite Threadlocker Guide for the right product. Threadlockers (Loctite 222, 243, 270, and others) are a completely different product class — anaerobic adhesives that cure in the absence of oxygen, not cyanoacrylates. Loctite 401 Technical Specifications The table below summarises the key performance properties from the Henkel technical data sheet. These values apply at 22°C unless otherwise stated. Property Value Chemistry Ethyl cyanoacrylate (ECA) Appearance Clear, colourless liquid Viscosity (Brookfield) 100–120 mPa·s (medium viscosity) Specific gravity 1.1 at 25°C Fixture time 3–10 seconds (substrate dependent) Full cure 24 hours at 22°C Operating temperature –55°C to +80°C Shear strength — steel ~14 N/mm² Shear strength — aluminium ~12 N/mm² Shear strength — NBR rubber ~9 N/mm² Maximum bond gap <0.1 mm Shelf life (unopened, 2–8°C) 12 months After opening Use within 30 days Available sizes 3 g, 25 ml, 100 ml What Can Loctite 401 Bond? Loctite 401 bonds a wide range of substrates. The table below lists typical fixture times by surface type at 22°C and 50% relative humidity. Fixture time is the point at which the assembly can be handled without disturbing the bond — full strength requires 24 hours. Substrate Typical Fixture Time Notes Steel (degreased) 3–5 seconds Excellent adhesion Aluminium 5–10 seconds Excellent adhesion Galvanised steel 5–10 seconds Surface-insensitive formula performs where standard CA adhesives may not Chromated / zinc-plated metal 5–10 seconds Surface-insensitive advantage Stainless steel 10–30 seconds Passive surface — use activator SF 7457 if speed required ABS plastic 5–15 seconds Good adhesion Acrylic (PMMA) 5–15 seconds Good adhesion; avoid solvent-sensitive grades Polycarbonate 10–20 seconds Adequate; use 406 for better results on large PC surfaces Nylon / PA 10–20 seconds Adequate adhesion NBR (nitrile rubber) 5–10 seconds Good adhesion, ~9 N/mm² EPDM rubber 5–15 seconds Good adhesion; use 406 for best results Natural rubber 5–10 seconds Good adhesion Ceramic 10–20 seconds Good adhesion on clean, dry surfaces Wood / cardboard 5–15 seconds Good; moisture in porous materials aids cure Polyethylene (PE) Poor without primer Use SF 770 primer first Polypropylene (PP) Poor without primer Use SF 770 primer first PTFE (Teflon) Poor without primer Use SF 770 primer first Silicone rubber Very poor Not recommended — use silicone-specific adhesive Gap fill limitation: Loctite 401 is optimised for close-fitting joints with a bond gap under 0.1 mm. Performance drops off significantly as gap increases — it will not bridge or fill visible gaps. For gaps of 0.1–0.5 mm, use Loctite 454 gel. For structural gap filling, use an epoxy. Is Loctite 401 the Same as Super Glue? Same chemistry, different product. Both Loctite 401 and consumer super glues are ethyl cyanoacrylate — the underlying cure mechanism is identical. The differences are in formulation, consistency, and intended use. Property Loctite 401 (Prism) Consumer Super Glue Chemistry Ethyl cyanoacrylate Ethyl or methyl cyanoacrylate Surface sensitivity Surface-insensitive formulation Standard — may fail on acidic/chromated surfaces Viscosity Controlled 100–120 mPa·s Variable, unspecified Shear strength ~14 N/mm² on steel (specified) Not specified Shelf life 12 months (unopened, refrigerated) Typically 12 months, variable Quality consistency Industrial-grade, batch-controlled Variable Intended use Industrial, engineering, assembly Household repairs, hobbyist For one-off household repairs, consumer super glue is fine. For industrial assembly, fixturing, or any application where bond performance needs to be predictable and repeatable, the industrial Prism range is the correct choice. The defined specs matter — 14 N/mm² shear strength means something when you’re designing a joint. An unspecified consumer product does not. Loctite 401 vs 406 vs 480 vs 495 — Which Do You Need? The Prism range can look confusing from the outside. Here is a direct comparison of the four most commonly used industrial instant adhesives: Product Viscosity Best For Key Feature Avoid For 401 Medium (100–120 mPa·s) Metals, rigid plastics, rubber, porous materials — general purpose Surface-insensitive; works on chromated & acidic surfaces PE, PP, PTFE without primer; flexible joints; large gaps 406 Low (50–100 mPa·s) Difficult plastics (ABS, PC, acrylic), elastomers, rubbers Surface-active ingredient for low-energy plastics and elastomers Porous materials (less effective than 401); metals where 401 is adequate 480 Medium (100–500 mPa·s, black) Dynamic assemblies subject to shock, vibration, or impact Rubber-toughened; flexible, impact-resistant bond Where maximum shear strength is needed; visible joints (cures black) 495 Low (80–200 mPa·s) General purpose metals and plastics; similar range to 401 General-purpose CA; good all-rounder Less surface-insensitive than 401 on chromated/acidic surfaces Default choice rule: Start with 401 for metal-to-metal, metal-to-rigid plastic, and most rubber applications. Move to 406 if you’re bonding flexible plastics, soft elastomers, or difficult low-energy substrates. Move to 480 if the assembly experiences dynamic loading. Add SF 770 primer if the substrate is PE, PP, or PTFE regardless of which adhesive you choose. For threadlockers and thread sealants — completely separate products — see our Thread Locking and Sealing Guide. When to Use Primer or Activator With Loctite 401 Most bonding with Loctite 401 requires no additional products. Two situations call for a supplementary product. Loctite SF 770 — Polyolefin Primer Use SF 770 when bonding polyethylene (PE), polypropylene (PP), polytetrafluoroethylene (PTFE), or thermoplastic rubbers. These are “low-energy” surfaces — cyanoacrylates cannot wet them reliably without surface activation. Apply SF 770 by brush to one bond surface, allow it to dry (30 seconds), then immediately apply Loctite 401 to the primed surface and assemble. Do not apply activator to a primed surface. Activators — SF 7457, SF 7452, SF 7455 Use an activator when: The substrate is a passive metal (stainless steel, anodised aluminium, certain chromates) that cures slowly or inconsistently Your process requires faster than standard fixture time You are bonding in low-humidity conditions where atmospheric moisture is limited Apply activator to one bond surface by brush or spray. Apply Loctite 401 to the opposite surface. Assemble immediately. The activator provides the moisture source needed to initiate polymerisation and accelerates cure from seconds to near-instantaneous. Do not saturate the surface — a thin, even coat is sufficient. Activator vs primer — they are not the same: SF 770 modifies a low-energy surface to accept adhesive. Activators (SF 7457, SF 7452) initiate or speed up cure on surfaces that already accept CA adhesive but cure slowly. Using an activator on PE or PP without primer will not solve the adhesion problem. How to Apply Loctite 401 Follow these steps for a clean, strong bond. Clean both surfaces. Remove oil, grease, dust, and release agents with isopropanol or acetone — or a purpose-formulated industrial degreaser. Dry completely. Surface contamination is the most common cause of bond failure. Check the fit. The joint gap must be less than 0.1 mm. If surfaces are rough or mismatched, address this before bonding. Cyanoacrylate is not a gap filler. Apply adhesive to one surface only. A single thin film is sufficient — typically one drop per 6–10 cm² of bond area. Less is more. Excess adhesive slows cure, reduces strength, and causes bloom. Assemble immediately. Position the parts and apply firm contact pressure for 5–10 seconds. Do not slide parts relative to each other after contact. Allow fixture time before handling. The assembly can be carefully moved after 10–30 seconds. Avoid loading the joint for at least 15 minutes; allow 24 hours before applying full design load. Remove excess adhesive promptly. Uncured adhesive on adjacent surfaces can be wiped with acetone before it cures. Cured adhesive can be removed mechanically or with Loctite SF 7200 debonder. Skin contact: Cyanoacrylate bonds skin immediately. Wear nitrile gloves when working with Loctite 401. If skin bonding occurs, immerse in warm soapy water and peel apart gently — do not pull forcefully. Acetone (nail polish remover) applied after soaking will help separate bonded skin. Common Failures and How to Fix Them White residue (bloom / frosting) around the joint Cause: Excess adhesive vapourises during cure, reacts with atmospheric moisture, and deposits as white polymer residue on nearby surfaces. Fix: Reduce the quantity of adhesive applied. Ensure good ventilation at the bond site. In high-humidity environments, use activator to accelerate cure and minimise vapour off-gassing. Bloom is cosmetic — the bond itself is structurally sound. Brittle bond — joint cracks or fails under vibration or impact Cause: Loctite 401 produces a rigid bond that does not flex. Dynamic loading, vibration, or impact will crack a 401 bond line over time. Fix: Switch to Loctite 480 (rubber-toughened cyanoacrylate) for assemblies subject to dynamic loads. If flexibility is required, consider a polyurethane or MS-polymer adhesive. Poor adhesion or bond failure on plastics Cause: The substrate is a low-energy plastic (PE, PP, PTFE, TPR) that CA adhesives cannot wet reliably. Fix: Apply Loctite SF 770 polyolefin primer before bonding. For challenging plastics that are not polyolefins (e.g. silicone), the adhesive technology needed is different — neither 401 nor 406 will work reliably without an appropriate primer or alternative adhesive system. Very slow cure on metal Cause: Passive metal surfaces (stainless steel, anodised aluminium, certain chromates) lack the surface reactivity and moisture needed to initiate rapid CA cure. Fix: Apply activator SF 7457 or SF 7452 to one bond surface. Assemble immediately after applying Loctite 401 to the opposite surface. Bond weakens or fails after a short period in service Cause: Most commonly, surface contamination prior to bonding — particularly oil or grease residue that was not fully removed. Also possible: excessive bond gap, or the joint is loaded in peel (cyanoacrylates are weak in peel — joint design should favour shear). Fix: Degrease thoroughly before bonding. Redesign the joint to load in shear rather than peel where possible. If peel resistance is critical, use a structural epoxy instead. Removing Loctite 401 — Debonding and Disassembly Cured cyanoacrylate is harder to remove than people expect. There are three reliable approaches depending on the situation. Mechanical removal For metal-to-metal or rigid assemblies, apply heat using a hot air gun. Loctite 401 begins to degrade above 80°C. Once the bond softens, pry apart with a flat tool. The bond area will need cleaning and degreasing before re-bonding. Chemical debonder — Loctite SF 7200 Loctite SF 7200 is a specialist debonder formulated to soften cured cyanoacrylate. Apply to the bond line and allow to soak for 30 minutes to several hours depending on joint size. The adhesive will soften enough to allow disassembly. Not suitable for all plastics — test on an inconspicuous area first. Acetone (nail polish remover) Acetone dissolves uncured and lightly cured cyanoacrylate effectively. For recently bonded joints that have not reached full cure, acetone applied directly to the bond line may allow disassembly. For fully cured bonds, it has limited effect without extended contact. Not suitable for polycarbonate, acrylic, or ABS plastics — acetone will craze or dissolve these surfaces. Skin bonding: If skin contact bonds occur, immerse in warm soapy water and gently peel apart. Do not pull forcefully. Once loosened, acetone (nail polish remover) assists in separating bonded skin. Medical attention is rarely required unless eyes are involved — eye contact requires immediate flushing with water and medical review. Typical Applications in Industrial Settings Loctite 401 appears across a wide range of industries and tasks. The following are common Australian industrial applications. Manufacturing and assembly Fixture bonding in production lines — temporarily or permanently locating small components during assembly before a secondary adhesive, fastener, or weld is applied. Also used for permanent bonding of nameplates, labels, gaskets, and sensor housings. Maintenance and repair Workshop repairs of rubber seals, gaskets, and hose fittings. Bonding cracked plastic housings, guards, and covers. Reattaching rubber bumpers, feet, and anti-vibration mounts on machinery. Automotive and fleet Trim and moulding bonding, rubber seal repair, interior plastic repairs. Note that Loctite 401 is not rated for continuous fuel or oil immersion — for such applications, a fuel-resistant adhesive is required. Electronics and instrumentation Bonding small electronic components, strain relief, sensor mounting. Loctite 401 is electrically non-conductive after cure, making it suitable for low-voltage insulating applications where the adhesive is not exposed to high temperatures. What Loctite 401 is not suited for Structural load-bearing applications (use structural epoxy). Joints subjected to peel loads (CA adhesives are weak in peel — redesign the joint or use epoxy). Surfaces continuously immersed in water or solvents. High-temperature applications above 80°C. Flexible or elastomeric assemblies subject to repeated flexing (use 480 or polyurethane adhesive). For load-bearing or gap-filling bonds where cyanoacrylate is unsuitable, two-part epoxy adhesive is the typical alternative. Loctite 401 Storage and Shelf Life Cyanoacrylate adhesives cure on contact with moisture — including atmospheric moisture. Storage conditions directly affect product life. Condition Guidance Unopened, refrigerated (2–8°C) 12 months shelf life Unopened, room temperature Reduced shelf life — check date regularly Opened — store at Room temperature (NOT refrigerated) After opening — use within 30 days for best performance Cap Reseal tightly after every use Keep away from Direct sunlight, heat sources, humidity Why not refrigerate after opening? When a cold bottle is brought out of the fridge, it warms up and condensation forms inside the container. That moisture initiates polymerisation — effectively curing adhesive inside the bottle. Store opened product at stable room temperature and keep the cap sealed between uses. If the adhesive is stringing, gelling, or producing poor bonds, the product has likely degraded and should be replaced. Attempting to use expired or partially cured product produces unreliable results. Loctite 401 is one of several adhesive types used in Australian industry. Cyanoacrylate instant adhesives are ideal for small, close-fitting joints with fast fixture requirements — but they are not the right choice for every application. For a complete comparison of adhesive types — including contact adhesive, epoxy, anaerobic threadlockers, structural acrylic, and RTV silicone — see the Industrial Adhesive Types Guide. Frequently Asked Questions What is Loctite 401 used for? Loctite 401 is a medium-viscosity instant adhesive (cyanoacrylate) designed for industrial bonding of metals, rigid plastics, rubber, ceramics, and porous materials such as wood and cardboard. It is surface-insensitive, meaning it bonds reliably on acidic or chromated surfaces where standard super glues fail. Typical applications include fixture bonding in manufacturing, rubber gasket assembly, small metal component bonding, and any application requiring a fast, strong bond on close-fitting joints. Is Loctite 401 the same as super glue? Loctite 401 and consumer super glue share the same chemistry — both are ethyl cyanoacrylate (ECA) — but they are not the same product. Loctite 401 is part of the industrial Prism range and is formulated to be surface-insensitive, meaning it performs reliably on difficult surfaces such as chromate-treated metals and acidic substrates where standard super glue often fails. It also has defined viscosity and shear strength specifications, a controlled shelf life, and consistent industrial-grade quality. Consumer super glues are unspecified, variable in performance, and generally unsuitable for industrial or engineering applications. What is the difference between Loctite 401 and 406? Both are industrial instant adhesives, but they are optimised for different applications. Loctite 401 is a general-purpose, surface-insensitive formula that bonds metals, rigid plastics, rubber, and porous materials. Loctite 406 is specifically formulated for difficult-to-bond plastics (including ABS, polycarbonate, and acrylic) and elastomers — it contains a surface-active ingredient that improves adhesion to low-energy surfaces. For most metals and mixed-substrate assemblies, 401 is the better choice. For challenging plastics and rubber applications, 406 is preferred. Does Loctite 401 need to be refrigerated? Unopened bottles of Loctite 401 should be stored refrigerated at 2–8°C to achieve the full 12-month shelf life. However, once opened, do NOT refrigerate the bottle. Returning an opened bottle to the fridge causes condensation inside the container when it warms up, and that moisture will prematurely cure the adhesive. After opening, store at room temperature in a dry location, keep the cap tightly sealed, and use the product within 30 days for best performance. What is the fixture time of Loctite 401? Loctite 401 fixtures (reaches handling strength) in 3 to 10 seconds on most substrates at room temperature, depending on the surface type, humidity level, and bond gap. Steel and aluminium typically fixture at the faster end of this range. Inactive metals such as stainless steel or anodised aluminium may be slower. Full cure to rated strength takes 24 hours at 22°C. If faster cure is needed, use activator LOCTITE SF 7457 or SF 7452 on one bond surface. What temperature can Loctite 401 withstand? Cured Loctite 401 has an operating temperature range of –55°C to +80°C. It maintains bond integrity through both freezing conditions and elevated heat up to 80°C. For applications requiring higher temperature resistance, consider Loctite 4014 (rated to +120°C) or a structural epoxy adhesive. Can Loctite 401 bond rubber? Yes, Loctite 401 bonds most common rubber types including NBR (nitrile), natural rubber, EPDM, and neoprene. On NBR rubber, the shear strength is approximately 9 N/mm². The surface-insensitive formulation helps with the variability in rubber surface chemistry. For difficult elastomers such as silicone, PTFE-based materials, or very low-energy thermoplastic rubbers, Loctite 406 combined with SF 770 primer is the more reliable choice. Where a more flexible or gap-filling bond is required, flexible epoxy adhesive or polyurethane adhesive is more appropriate for rubber substrates. Can Loctite 401 bond polyethylene or polypropylene? Not reliably without surface preparation. Polyethylene (PE) and polypropylene (PP) are low-surface-energy plastics that resist bonding with standard cyanoacrylate adhesives, including Loctite 401. To bond PE or PP, apply Loctite SF 770 polyolefin primer to the surface, allow it to dry, then apply Loctite 401 (or 406) immediately. The primer activates the low-energy surface and enables a strong bond. Without primer, expect poor adhesion and early bond failure. Why is my Loctite 401 turning white (blooming)? White residue or frosting around the bond line — known as bloom — is caused by excess cyanoacrylate vapour curing on contact with ambient moisture. It happens when too much adhesive is applied, when humidity is high, or when ventilation is poor. To prevent bloom: use the minimum effective quantity of adhesive (a thin film is sufficient for close-fitting joints), ensure good ventilation, and if working in humid conditions, use activator SF 7457 to speed up cure and reduce vapour off-gassing. Bloom is cosmetic, not structural — the bond itself is unaffected. What is the maximum gap Loctite 401 can fill? Loctite 401 is optimised for close-fitting joints with bond gaps of less than 0.1 mm. It is not a gap-filling adhesive — performance degrades significantly with increasing gap size, and it will not bridge or fill visible gaps reliably. For loose-fitting joints or irregular surfaces with gaps of 0.1–0.5 mm, use Loctite 454 instant adhesive gel. For larger gaps or structural repairs, use an epoxy adhesive. What is the difference between Loctite 401 and 480? Loctite 401 produces a rigid, high-strength bond optimised for stiff assemblies and close-fitting joints. Loctite 480 is a rubber-toughened, flexible cyanoacrylate that produces a lower-strength but impact- and vibration-resistant bond — it appears black after cure. Use 401 where maximum shear strength is required on stable, non-flexing assemblies. Use 480 where the joint will experience dynamic loads, shock, or vibration, or where some bond flexibility is needed to prevent cracking. How do I speed up Loctite 401 cure time? Apply Loctite activator SF 7457 or SF 7452 to one bond surface before assembling the joint. The activator reacts with the cyanoacrylate on contact and accelerates cure to within seconds. This is particularly useful on passive metals (stainless steel, anodised aluminium) where natural cure can be slow. Do not apply activator to primed surfaces (SF 770). Alternatively, slightly increasing ambient humidity or temperature (within the product's working range) also speeds cure. Buy Loctite 401 from AIMS Industrial AIMS Industrial stocks Loctite 401 Prism Instant Adhesive in 3 g and 25 ml sizes, available online with fast Australia-wide delivery. Shop Loctite 401 Instant Adhesive → For other Loctite products including threadlockers, thread sealants, and retaining compounds, see our full Loctite Threadlocker and Industrial Adhesive Guide. For medium-strength threadlocker specifically, see the Loctite 243 Guide. Need o-rings? The AIMS O-Ring range includes nitrile, Viton, EPDM, silicone and PTFE compounds. People Also Ask — Loctite 401 Instant Adhesive Q: How fast does Loctite 401 cure? On steel and aluminium, Loctite 401 achieves fixture strength in under 5 seconds at 22°C and 50% relative humidity. Full chemical and solvent resistance develops after 24 hours, with full strength reached between 24 and 72 hours depending on substrate and conditions. Cure is faster on porous materials (rubber, leather) and slower on glass and acidic surfaces such as some woods. Q: What surfaces does Loctite 401 not bond? Loctite 401 does not reliably bond polyethylene (PE), polypropylene (PP), PTFE, or silicone rubber without a surface primer. It also bonds poorly to oily or contaminated surfaces, and gaps over approximately 0.1 mm will significantly reduce strength as cyanoacrylate requires close contact to cure. Pre-treat difficult plastics with Loctite Primer SF 770 before application. Q: How should Loctite 401 be stored? Store Loctite 401 in a refrigerator between 2°C and 8°C and keep the cap tightly closed after each use. Shelf life is 12 months from manufacture when stored correctly. At room temperature, expect a shorter working life once opened. Do not freeze. Allow the bottle to reach room temperature before opening to prevent condensation from entering the applicator tip. Q: What is the difference between Loctite 401 and Loctite 406? Loctite 401 is a general-purpose medium-viscosity ethyl cyanoacrylate for metals, ceramics, and most plastics. Loctite 406 is specifically formulated for rubber and difficult plastics, with improved bonding to EPDM, neoprene, and polycarbonate. If bonding rubber or soft plastics is the primary application, use 406. For mixed-substrate production or maintenance work, 401 is the more versatile option. Q: Can Loctite 401 withstand heat? Loctite 401 maintains meaningful bond strength up to approximately 80–90°C in continuous service. For short-term or peak exposure, strength is retained to around 120°C before significant reduction. For elevated-temperature applications above 80°C, consider Loctite 4014 or 4061, which are cyanoacrylate grades with higher heat resistance, or switch to an epoxy adhesive for sustained high-temperature service.
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Loctite 243 is the most widely used threadlocker in Australian industrial and maintenance applications. Walk into any workshop, service bay, or trade.
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Thread locking and thread sealing are not the same thing — they solve different problems with different products, and using the wrong one for the job.
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Loctite Application Guide: Which Grade & When to Use It
Loctite Grade Selector — Match Product to Job This guide is a working Loctite selector. Use the cards below to land on the right grade fast — every grade mentioned in the article body also links to its specific AIMS product page. How to use: 1. Match the job profile (threadlock, sealant, retaining, adhesive) 2. Click the grade to view AIMS stock 3. Use the application section below for technique Low-Strength Threadlock Loctite 222 — small fasteners, removable 222 View → Medium-Strength Threadlock Loctite 243 — workshop default 243 View → High-Strength Threadlock Loctite 263 / 271 — permanent / vibration 263/271 View → Pipe Thread Sealing Loctite 567 / 569 / 577 — anaerobic 567/577 View → Bearing Retaining Loctite 638 / 641 — slip-fit retaining 638 View → Gasket Eliminator Loctite 518 / 510 / 587 / 596 518/596 View → Instant Adhesive (CA) Loctite 401 / 406 / 480 401/406 View → Anti-Seize / Surface Prep Loctite Copper Anti-Seize + 7649 Primer Anti-Seize View → Quick rule of thumb: Loctite anaerobics cure where there's metal + absence of oxygen. Low-strength (222) = removable. Medium-strength (243) = workshop default. High-strength (263/271) = permanent / heat-required to remove. AIMS stocks the full Loctite anaerobic + instant adhesive + sealant + activator range. Need help? Call (02) 9773 0122. Jump to: Which Loctite? Quick Chart Threadlockers Thread Sealants Retaining Anti-Seize Surface Prep Removing Instant Adhesives Related Which Loctite do I use? Loctite threadlockers are colour-coded by strength: blue (Loctite 242 / 243) for medium-strength fasteners you'll need to remove later, red (Loctite 262 / 271 / 277) for permanent high-strength fasteners that stay put, and green (Loctite 290) for wicking into pre-assembled threads. Loctite also makes thread sealants (567 / 577 for tapered pipe threads), retaining compounds (603 / 638 for bearing fits), and instant adhesives (401 / 406 cyanoacrylates). What is Loctite 243 used for? Loctite 243 is a medium-strength blue threadlocker for fasteners between M6 and M20 that you may need to remove later with hand tools. It tolerates light oil contamination on the threads, cures in around 10 minutes to handling strength, and reaches full strength in 24 hours. Typical uses: vehicle suspension bolts, pump and motor fixings, machinery hold-downs, gearbox fasteners. Need another reference chart? Browse the full AIMS Engineering Reference Charts library — drill bit sizes, tap drill, torque, viscosity, GD&T, AS/NZS standards and more. Loctite Quick Selection Chart For threadlocking on small fasteners use Loctite 222 (purple); medium-duty fasteners Loctite 243 (blue); high-strength permanent Loctite 263 or 271 (red). For pipe sealing use Loctite 567 or 577. For retaining compounds use Loctite 638, 641 or 648. Full grade-by-grade detail below. Grade Type / Colour Use For 222 Threadlocker — Purple, low strength Small screws M1.4–M6, grub screws, instruments 243 Threadlocker — Blue, medium strength General fasteners M6–M20, hand-tool removable 263 / 271 Threadlocker — Red, high strength Permanent fasteners — heat required to remove 567 Thread sealant — White Fine hydraulic and pneumatic threads 577 Thread sealant — Yellow BSP and NPT pipe threads, gas, water, oil 638 Retaining compound — High strength Close-tolerance bearing retention 641 Retaining compound — Medium strength Standard bearing / bushing retention 648 Retaining compound — Maximum strength Permanent high-temp cylindrical assemblies 401 Instant adhesive — Cyanoacrylate General-purpose bonding of metal, rubber, plastic 480 Instant adhesive — Toughened CA Impact-resistant rubber and metal bonds What Are Loctite Anaerobic Products? Loctite's industrial range is built on anaerobic chemistry — adhesives and sealants that remain liquid in air but cure rapidly when trapped between two close-fitting metal surfaces in the absence of oxygen. The metal ions in the substrate initiate polymerisation, converting the liquid into a hard thermoset plastic that resists vibration, leakage and corrosion. When stripping a stubborn old anaerobic threadlocker bond, mechanical heat is the standard release method — but for plastic-bodied components where heat is risky, the contrast-cooling trick from our freeze spray guide can shock-fracture cured threadlocker without damaging the surrounding plastic. Quick answer — Loctite grades by job Threadlockers (anaerobic, prevent vibration loosening): 222 low strength (small screws, removable) · 242/243 medium strength (general purpose, blue) · 263/271/277 high strength (permanent, red) · 248 stick form Instant adhesives (cyanoacrylate / super glue): 401 general purpose · 406 rubber/plastic specialty · 414 metals · 480 toughened impact-resistant · 435 low-blooming clear Thread sealants (anaerobic, pipe thread leaks): 567 stainless/coarse (white) · 577 general pipe (yellow, faster cure) · 542 hydraulic fine threads · 545 general purpose Retaining compounds: 603 oil-tolerant · 638 high strength, high temp · 648 high temp, fast cure · 680 slip-fit highest strength This guide covers every industrial Loctite product family relevant to maintenance, engineering and trade work in Australia: threadlockers (preventing fastener loosening under vibration), thread sealants (sealing pipe and hydraulic fittings), and retaining compounds (locking bearings, bushings and cylindrical assemblies). It includes full selection charts, application guides, cure time data, surface preparation requirements and removal instructions — plus a FAQ section that answers the most common grade comparison questions. Browse the full AIMS Industrial Loctite range — threadlockers, thread sealants, retaining compounds and primers stocked for fast Australia-wide dispatch. Loctite Threadlockers: Grades, Colours and Selection Threadlockers prevent fasteners from loosening under vibration, thermal cycling and dynamic load. They fill the microscopic gaps between mating threads, locking out corrosion and sealing against fluid ingress at the same time. Selecting the wrong grade — typically using red where blue is correct, or blue where purple is required — is the most common installation mistake, and can make fasteners impossible to remove without heat or damage the threads on small screws. The Loctite Colour and Strength System Every Loctite threadlocker is colour-coded by strength. The colour tells you immediately whether the fastener can be released with standard hand tools or whether heat will be required for removal. Colour Strength Level Removability Common Grades Purple Low Hand tools — easily removable 222 Blue Medium Hand tools — standard spanners and sockets 242, 243 Red High / Permanent Heat required — 250°C before applying torque 262, 263, 271, 272, 277 Green Low to High (wicking grades) Depends on grade — see table below 270, 290 Loctite Threadlocker Grade Comparison Chart Grade Colour Strength Bolt Size Max Temp Removable? Primary Application 222 Purple Low M1.4–M6 150°C Yes — hand tools Small screws, grub screws, instrument hardware, adjustment fasteners 242 Blue Medium M6–M20 150°C Yes — hand tools General purpose — older formulation; performs identically to 243 on clean threads 243 Blue Medium M6–M20 150°C Yes — hand tools General purpose standard — improved oil tolerance over 242; preferred current-generation grade 262 Red High M6–M20 150°C Heat required (250°C) Studs, press-fit bolts, high-vibration assemblies — smaller fasteners than 263 263 Red High M6–M36 150°C Heat required (250°C) Large permanent fasteners — higher breakaway torque than 262; structural joints 270 Green High M6–M36 150°C Heat required Wicking grade — penetrates pre-assembled joints; post-assembly application 271 Red High M6–M36 150°C Heat required (250°C) High-strength general purpose — wheel bolts, studs, structural and safety-critical fasteners 272 Red High M6–M36 230°C Heat required High-temperature applications — exhaust manifold studs, engine components, hot environments 277 Red Very High M20–M36+ 150°C Heat required Very large fasteners — maximum breakaway torque for flanges, heavy plant, large structural bolts 290 Green Medium M6–M20 150°C Yes — hand tools Wicking grade — post-assembly on pre-assembled or production-line fasteners; medium strength Loctite 242 vs 243 — What Changed? Loctite 243 is the current-generation replacement for 242. Both are medium-strength blue threadlockers for M6–M20 fasteners, and both develop the same cured strength on clean, degreased steel. The key improvement in 243 is better tolerance to light oil contamination on threads. In a workshop environment where threads are occasionally oily, 243 cures reliably where 242 may underperform. If you have 242 on the shelf, use it — it is equivalent to 243 on clean surfaces. For new stock, specify 243. Loctite 243 vs 263 — The Most Important Distinction This is the most common and consequential selection decision. The choice is simple: will this fastener ever need to be removed? Use 243 (blue) when the fastener may need to be removed for service, adjustment or replacement. Under vibration, 243 provides equivalent security to red — it will not self-loosen. But a standard spanner or socket applied with normal force will break the bond. This is the correct grade for brake caliper bolts, suspension components, machinery access panels, and any fastener in the service path. Use 263 or 271 (red) when the assembly is permanent — a structural joint, a stud that will never be pulled, or a high-vibration application where even low probability of movement is unacceptable. These grades require heating to 250°C before the fastener can be turned. Using red on a service fastener, or on a small bolt where that heat cannot be applied safely, is the most common Loctite misapplication on the workshop floor. Threadlocker Application Selection Guide Application Recommended Grade Reason Small adjustment screws, grub screws, M1.4–M6 222 (Purple) Low strength only — blue or red on small threads risks stripping or irreversible locking General fasteners requiring future service access, M6–M20 243 (Blue) Medium strength, hand-tool removable, the standard industrial choice Brake caliper bolts 243 (Blue) Service access required; OEM specification for most passenger and light commercial vehicles Wheel spacer bolts 243 (Blue) Vibration resistance with removability for tyre changes and wheel service Bicycle and bike component bolts 222 (Purple) Critical — titanium and aluminium threads cannot handle medium or high strength; purple only Flywheel bolts, ring gear bolts 263 or 271 (Red) Permanent structural joint; high vibration; rarely or never removed in service life Exhaust manifold studs, turbo bolts 272 (Red) High-strength with 230°C continuous service temperature — the only threadlocker rated for exhaust temperatures Pre-assembled joints — wicking application 290 (Green, medium) or 270 (Green, high) Low viscosity penetrates assembled threads via capillary action — apply externally after assembly Large structural fasteners M20 and above 277 (Red) Maximum breakaway torque for large thread engagement in heavy plant and structural applications Stainless steel fasteners into stainless 243 + Loctite 7649 Activator N Passive metal — requires activator for reliable cure; see surface preparation section below Stainless Steel, Aluminium and Other Passive Metals Loctite anaerobic products cure by reacting with the metal ions present in the substrate. Passive metals — stainless steel, aluminium, titanium, zinc plating, cadmium plating — have an oxide layer that slows or prevents this reaction. On stainless-to-stainless assemblies without treatment, cure may be incomplete, slow (days rather than hours), or fail entirely in cold conditions. The solution is Loctite 7649 Activator N: apply a thin coat to one mating surface, allow 30–60 seconds to dry, then apply the Loctite threadlocker to the other surface and assemble normally. The activator overcomes the passive layer and initiates rapid, complete cure. This step is not optional on stainless — it is the difference between a joint that works and one that fails at the worst moment. Loctite Thread Sealants: Pipe, Hydraulic and Gas Applications Thread sealants seal tapered and parallel pipe threads against leakage of fluids and gases under pressure. They are a distinct product family from threadlockers — they are formulated for sealing pipe thread profiles (BSP, NPT, metric parallel), not for retaining standard bolts and fasteners. Product Type Max Pressure Max Temp Potable Water Best For Loctite 55 Sealing cord (PTFE alternative) 80 bar (gas) / 100 bar (liquid) −50°C to +130°C Yes — NSF 61 certified Gas, water, hydraulic; plastic and metal threads; instant pressure resistance on assembly Loctite 542 Anaerobic liquid 350 bar −65°C to +150°C No Fine metal hydraulic threads — instrumentation fittings, precision pneumatic connections Loctite 567 Anaerobic liquid 690 bar −65°C to +150°C No Metal pipe threads — hydraulic, pneumatic, fuel and oil systems; fine thread forms Loctite 577 Anaerobic liquid 400 bar −55°C to +150°C No Coarser BSP and NPT metal pipe threads — compressed air, water, oil and gas plumbing Loctite 55 — The PTFE Thread Seal Alternative Loctite 55 is not an anaerobic liquid — it is a continuous-filament sealing cord wound around threads by hand, replacing PTFE tape. Wound clockwise around the male thread (three to five turns for most fittings), it creates an immediate, compliant seal that develops full holding strength as the fitting is tightened. Its key advantages over PTFE tape: it can be hand-tightened to immediate pressure resistance with no cure wait; it works reliably on both metal and plastic fittings; it does not shred or delaminate into pipework; and it can be repositioned slightly after assembly if alignment is needed. Most importantly for Australian trade and construction applications, Loctite 55 is NSF 61 certified for potable water — it is the correct Loctite product for drinking water connections. It is also approved for gas service and is used on residential and commercial gas fittings where threaded connections are required. Loctite 567 vs 577 — Which Anaerobic Thread Sealant? Both 567 and 577 are anaerobic liquids that seal metal pipe threads. The difference is viscosity and thread form. Loctite 567 is lower viscosity — it wicks easily into fine hydraulic and pneumatic thread forms (SAE, metric fine), making it the correct choice for instrument fittings, hydraulic block connections and precision pneumatic assemblies where thread tolerances are tight. Loctite 577 is higher viscosity — it stays in place on coarser BSP and NPT threads during assembly, making it the standard choice for compressed air systems, water fittings and general industrial plumbing. If in doubt on a BSP fitting, use 577. If connecting hydraulic instrument tubing or fine metric threads, use 567. For cure times, fluid compatibility, passive metal guidance and a full application guide, see our Loctite 577 Thread Sealant Guide. Loctite Retaining Compounds: Bearing and Cylindrical Assembly Retaining compounds bond cylindrical assemblies — shaft-to-bearing, shaft-to-hub, pin-to-bore — by filling the microscopic clearance between components and polymerising into a rigid, load-bearing joint. They are used to augment or replace interference fits, to prevent fretting corrosion in light-clearance assemblies, and to salvage worn bores where a bearing has become loose in its housing. The two critical selection variables are the radial clearance between the mating components and the strength required. Using a product with a maximum clearance smaller than the actual gap will result in incomplete fill and significantly reduced bond strength. Grade Strength Max Clearance Max Temp Re-assemble? Best For 609 Low 0.10 mm 150°C Yes — press or hand Light-duty retention, small close-tolerance assemblies requiring re-use 638 High 0.15 mm 150°C With press or puller Close-tolerance bearing retention — maximum strength where fit is tight 641 Medium 0.25 mm 150°C Yes — press or puller Standard bearing and bushing retention — strength with serviceability 648 Maximum 0.15 mm 175°C Effectively no Permanent high-temperature assemblies where disassembly is never required 660 High 0.50 mm 150°C With press or puller Worn bore salvage — fills large clearances in worn housings and shafts 680 High 0.35 mm 150°C With press or puller General-purpose medium-to-large clearance bearing retention Choosing Between 638, 641 and 648 For new bearings in a correctly toleranced housing, 641 is the default choice. Medium strength, 0.25 mm maximum clearance, and removable with a standard bearing puller or hydraulic press — this covers the vast majority of bearing retention applications in industrial and agricultural equipment. Use 638 when the fit is very close and maximum strength is required. In a tight housing where interference fit alone is nearly sufficient, 638 augments the fit to create an exceptionally strong, permanent joint. Note that 638 in a tight bore with a light press fit is very difficult to disassemble — treat it as semi-permanent. Use 648 only when the assembly will never be disassembled and operating temperatures exceed 150°C. Loctite 648 is the most thermally resistant retaining compound and produces the highest bond strength in the range — but the joint is effectively destroyed on any attempt at disassembly. Reserve it for permanent high-temperature applications such as motor shaft assemblies in hot environments. For worn bores where the bearing is loose in the housing (clearance beyond 0.25 mm), use 660. It fills gaps up to 0.5 mm, locks the bearing in the oversized bore, and restores the housing to service without machining. This is the most commonly used retaining compound in field service and overhaul environments where worn machinery is being returned to service. Browse AIMS Industrial's full Loctite retaining compound range including 638, 641, 648 and 660. Loctite Anti-Seize Anti-seize does the opposite of a threadlocker. Where threadlockers lock fasteners in place by filling the thread void, anti-seize prevents fasteners from seizing, galling and corroding in ways that make them impossible to remove. Never apply both to the same fastener. Loctite C5-A Copper Anti-Seize is the industrial standard — a copper-based paste rated to 980°C. Correct applications include stainless-on-stainless assemblies where galling is a risk (anti-seize is far more effective than threadlocker at preventing galling), exhaust bolts and manifold studs subject to repeated heat cycling, fasteners in corrosive environments such as marine, chemical plant and agricultural equipment, and any assembly where long-term disassembly is essential. Important torque note: Anti-seize reduces the friction coefficient of threads. If torquing to a manufacturer specification designed for dry or lightly oiled threads, the torque value must be reduced when anti-seize is applied — typically by 20 to 25%. Applying full dry-thread torque with anti-seize present will over-stress the fastener. Surface Preparation: The Critical Step Loctite anaerobics cure by reacting with metal ions in the substrate. Surface contamination — oil, grease, coolant, cutting fluid, rust preventative — inhibits this reaction and reduces cured strength. Inadequate surface preparation is the primary cause of Loctite application failures. Standard preparation for all Loctite anaerobic products: Degrease both mating surfaces with Loctite 7063 cleaning solvent or isopropyl alcohol. Apply solvent, agitate if necessary to remove oil film, and allow to evaporate fully — do not assemble onto wet surfaces. On threaded fasteners, apply solvent to the bore threads and the bolt shank and allow to dry before applying Loctite. For passive metals (stainless steel, aluminium, titanium, zinc, cadmium plating): Apply Loctite 7649 Activator N to one surface and allow 30–60 seconds to dry before applying the Loctite product to the other surface. This step is not optional — without activator on stainless steel, cure is unreliable, particularly at temperatures below 15°C. The activator is low-cost and eliminates a significant failure mode. Cure Time Reference Product Type Grade Handling Strength (steel, 22°C) Full Cure Low-strength threadlocker 222 10 minutes 24 hours Medium-strength threadlocker 242, 243 10 minutes 24 hours High-strength threadlocker 262, 263, 271 20 minutes 24 hours High-temp threadlocker 272 20 minutes 24 hours (full high-temp rating requires post-cure at 120°C for 30 min) Wicking threadlocker 270, 290 15 minutes 24 hours Standard retaining compound 638, 641 10–15 minutes (fixture) 24 hours High-temp retaining compound 648 15 minutes (fixture) 24 hours (post-cure at 120°C recommended for full performance) Thread sealant 567, 577 Immediate pressure resistance 24 hours full cure Cold temperature note: Below 10°C, all cure times extend significantly — allow 48 to 72 hours for full cure in cold conditions. Cure can be accelerated to near-full strength by warming the assembled joint to 80°C for 30 minutes. On passive metals without activator, add 50% to all cure time estimates. Removing Loctite Threadlocker The correct removal method for any Loctite threadlocker — blue or red — is heat. Apply a heat gun or torch to bring the joint to approximately 250°C, then apply torque to the fastener immediately while the joint is still hot. The cured Loctite softens above this temperature and releases. Do not heat the joint and then allow it to cool before attempting removal — the Loctite will re-harden and lock the fastener again. Blue (medium strength) threadlocker: Heat to 250°C is effective but not always required. Strong, steady hand-tool force will release most blue-locked joints without heat. If a blue-locked fastener resists standard hand tool force, apply heat before increasing effort — forcing a locked fastener with an extension bar risks breaking the bolt or stripping the thread rather than releasing the Loctite. Red (high strength) threadlocker: Heat is not optional. Do not attempt to remove a red-locked fastener with hand tools alone — the breakaway torque exceeds what hand tools can safely apply on most bolt sizes. Apply direct heat to the joint, apply torque immediately while hot, and repeat the heat-and-torque cycle if the fastener does not break free on the first attempt. Aluminium and composite components: Use a heat gun rather than a torch to avoid warping or heat-damaging the surrounding material. Apply heat gradually and test the fastener for movement frequently rather than applying maximum heat in one go. If heat risks damaging adjacent components, soak the joint overnight with a penetrating oil to assist, then apply minimum heat to break free. After removal: Clean old Loctite from threads with a wire brush and solvent before re-applying fresh product. Do not re-apply new Loctite over hardened residue — the cured material does not dissolve or re-activate. Loctite Instant Adhesives: 401, 406 and the Cyanoacrylate Range Loctite's cyanoacrylate (CA) range — commonly called instant adhesives or superglue — are chemically distinct from the anaerobic products above. They cure by reacting with surface moisture rather than requiring the absence of oxygen or metal ions, and they are not suitable for thread locking, pipe sealing or cylindrical retention. Loctite 401 is the standard-viscosity general-purpose CA adhesive. It bonds metal, rubber, rigid plastics and most hard materials in seconds. For most instant adhesive applications in a trade or industrial workshop, 401 is the correct starting choice. See our Loctite 401 complete guide for full substrate compatibility, cure times and storage information. Loctite 406 is formulated for difficult substrates — polyolefin plastics (polyethylene, polypropylene), rubbers and elastomers that standard CA adhesives cannot reliably bond. It contains a surface-insensitive primer agent that promotes adhesion on low-energy surfaces. For bonding rubber seals to metal housings, or joining PP and PE components, 406 is significantly more reliable than 401. Loctite 454 is a gel-form CA that stays in position on vertical surfaces and fills small gaps — the correct choice where a liquid adhesive would run before the joint is closed, or where mating surfaces are slightly rough or porous. Loctite 480 is a rubber-toughened CA for applications requiring a flexible, impact-resistant bond — rubber-to-rubber and rubber-to-metal joints where a rigid brittle bond would crack under flexing. Loctite Product Equivalents The most frequently searched Loctite equivalent products come from the Permatex range. The approximate equivalents for the main industrial grades are: Loctite Grade Permatex Equivalent Notes 222 — Purple, low strength Permatex 24010 Functionally equivalent; verify application torque values independently 243 — Blue, medium strength Permatex 24200 Direct equivalent for general-purpose medium-strength applications 271 / 263 — Red, high strength Permatex 27200 High-strength equivalent; verify temperature ratings for your specific application When substituting between brands, always confirm that the equivalent grade meets your specific temperature, gap clearance and torque requirements — equivalent strength does not guarantee identical performance in all conditions. Lock it. Seal it. Trust it. Related AIMS Selectors This selector pairs with AIMS's other fastener & adhesive guides: Loctite 222 Guide — purple low-strength threadlocker deep-dive. Loctite 243 Guide — medium-strength workshop default. Loctite 401 Guide — instant adhesive (cyanoacrylate). Loctite 577 Guide — medium-strength thread sealant. Thread Locking & Sealing Guide — anaerobic chemistry + application technique. Industrial Adhesive Types Guide — broader adhesives hub: epoxy, RTV, structural. How to Remove Stuck Bolts & Nuts — when Loctite has done its job too well. Metric Bolt Torque Chart — torque values per grade and size. Or browse the full Loctite range, threadlockers, retaining compounds, gasket sealants, thread sealants, activators, cleaners & primers. Next-day Australia-wide dispatch from our Milperra warehouse. Shop the full Loctite range — threadlockers, retaining compounds & sealants From Loctite 222 low-strength to 263 high-strength threadlocker, 641 retaining compound, and 55 pipe sealant — AIMS Industrial is an authorised Loctite stockist with the full range available for fast Australia-wide dispatch. Shop Loctite at AIMS Talk to a specialist Frequently Asked Questions What is the best Loctite threadlocker for small screws?Loctite 222 (purple) is the only correct choice for screws up to M6. Small threads — grub screws, electronics fasteners, instrument hardware, adjustment screws — do not have sufficient thread engagement to handle the breakaway torque of medium or high-strength threadlocker. Applying blue (243) to an M3 or M4 grub screw will very likely make it impossible to remove without damaging the threads or the housing. Use purple (222) for anything M6 and smaller, without exception. What is the difference between blue and red Loctite?Blue Loctite (243) is medium strength and removable with hand tools — the standard choice for fasteners that need to be serviced, adjusted or replaced in the future. It will not self-loosen under vibration, but a spanner or socket applied with normal force will release it. Red Loctite (263, 271) is high strength and permanently locks the fastener — it requires heating the joint to 250°C before any torque will release it. The correct rule: if the fastener may ever need to come off, use blue. If it is a truly permanent structural joint, use red. Which Loctite threadlocker is the strongest?In the standard threadlocker range, Loctite 277 (red) has the highest breakaway torque and is formulated for large-diameter fasteners (M20–M36+). For the M6–M36 range, Loctite 263 and 271 provide effectively equivalent maximum strength for most applications. Loctite 648 is the maximum-strength retaining compound for cylindrical assemblies, though it serves a different function. For most industrial work, 271 or 263 provide more than sufficient permanent locking strength. Can Loctite cure on oily or contaminated threads?Standard threadlocker grades (242, 263) require clean, degreased surfaces for full strength development. Loctite 243 is formulated with improved oil tolerance and will cure acceptably on lightly oiled threads. On heavily contaminated or wet surfaces, no anaerobic product will achieve full strength — clean first. For post-assembly applications where disassembly is not practical, a wicking grade (290 for medium strength, 270 for high strength) applied to the external thread after cleaning the exposed surface will penetrate and lock the joint, but ultimate strength depends on the cleanliness of the thread interface. Can Loctite threadlocker be used on plastic threads?Anaerobic threadlockers require metal ions to cure and are formulated for metal-to-metal contact. On plastic threads, cure is unreliable, strength is substantially reduced, and certain Loctite formulations can stress-crack specific plastics — notably polystyrene and polycarbonate. For sealing plastic pipe fittings, use Loctite 55 sealing cord — it works on plastic threads without chemical incompatibility risk. For retention on plastic fasteners, mechanical solutions (nylon insert nuts, serrated flange fasteners) are more reliable than chemical threadlockers. Are Loctite thread sealants suitable for potable water pipes?Loctite 55 sealing cord is NSF 61 certified for potable water and is the correct Loctite product for any fitting in contact with drinking water. The anaerobic liquid sealants — 567 and 577 — are not NSF 61 certified and must not be used on potable water connections. For gas pipe connections (residential and commercial), Loctite 55 is also approved and is used on threaded gas fittings in Australia. It replaces PTFE tape in these applications with no need for cure time before pressurisation. How long does Loctite threadlocker take to fully cure?On clean steel at 22°C, most grades reach handling strength in 10–20 minutes — sufficient to torque the fastener and move the assembly without disturbing the joint. Full cure takes 24 hours. Below 10°C, cure times extend significantly — allow 48 to 72 hours at low temperatures. Cure can be accelerated by heating the assembled joint to 80°C for 30 minutes. On passive metals (stainless steel, aluminium) without activator, add at least 50% to all cure times and treat handling strength with caution. How do I remove a bolt locked with red Loctite threadlocker?Heat the joint directly to approximately 250°C using a heat gun or butane torch, then apply torque to the fastener immediately while it is still hot. The cured Loctite softens at this temperature and allows the fastener to turn. Do not heat the joint and then allow it to cool before trying — the Loctite re-hardens on cooling. If the fastener does not release on the first attempt, re-apply heat and try again. Never use an impact wrench on a locked fastener without heating first — the risk of shearing the bolt is significantly higher than the effort of applying heat. What is the difference between Loctite 567 and 577 thread sealant?Both are anaerobic liquids for sealing metal pipe threads. Loctite 567 is lower viscosity — it wicks easily into fine thread forms (SAE hydraulic fittings, metric fine, instrument connections) and is the correct choice for hydraulic and pneumatic precision connections. Loctite 577 is higher viscosity and stays in position on coarser BSP and NPT pipe threads during assembly. For most compressed air, water and gas plumbing on BSP fittings, 577 is the standard choice. For hydraulic block connections and instrument fittings with fine thread forms, use 567. See our full Loctite 577 Thread Sealant Guide for the complete application reference. Which Loctite retaining compound should I use for bearing retention?For standard bearing retention with normal bore clearance, Loctite 641 is the default choice — medium strength, handles clearances up to 0.25 mm, and the bearing can be removed with a press or standard puller for service. Use Loctite 638 for close-tolerance fits requiring maximum bond strength. Use Loctite 660 for worn bores with clearance above 0.25 mm — it fills gaps up to 0.5 mm and locks a loose bearing in an oversized housing without machining. Reserve Loctite 648 for permanent high-temperature assemblies that will never be disassembled. What is the difference between Loctite 401 and 406?Loctite 401 is a standard-viscosity cyanoacrylate (instant adhesive) for general bonding of metal, rubber and most rigid plastics. Loctite 406 is formulated specifically for difficult low-energy substrates — polyolefin plastics (polyethylene, polypropylene) and elastomers that standard CA adhesives cannot reliably bond. If you're bonding rubber gaskets, polypropylene fittings or PE components, 406 is the correct grade. For metal-to-metal, glass-to-metal or general rigid bonding, 401 is sufficient. The 406 premium is only justified where the substrate is a known adhesive-resistant plastic or rubber. For metric bolt diameter, pitch and head dimensions from M3 to M24, see our Metric Bolt Size Guide. People Also Ask — Loctite Grade Selection Q: What is the difference between Loctite 243 and Loctite 263? Loctite 243 is a medium-strength threadlocker removable with hand tools after cure — suitable for most fasteners M6 to M20 where future disassembly is expected. Loctite 263 is high-strength and permanently bonds fasteners; removal requires heat above 250°C. Use 243 for routine maintenance, 263 where vibration risk is severe and disassembly is not planned. Q: How long does Loctite threadlocker take to cure? Loctite 243 achieves handling strength in approximately 10 minutes on steel at 22°C. Full chemical cure takes 24 hours. Cure is slower on passive metals (stainless steel, zinc) and in cold conditions — allow extra time before applying service loads. Activator SF 7649 speeds cure on passive metals. Q: Can you use Loctite on aluminium threads? Yes. Loctite anaerobic threadlockers including Loctite 222, 243, and 263 are compatible with aluminium. Aluminium is a passive metal, so cure is slower than on steel. Apply Loctite Activator SF 7649 to one thread surface first to achieve reliable cure speed and strength on aluminium fasteners. Q: What Loctite grade is best for stainless steel fasteners? Loctite 243 medium-strength or Loctite 263 high-strength both work on stainless steel, but stainless is a passive metal — always apply Activator SF 7649 first. For stainless fasteners in food or hygienic environments, Loctite 2400 is a water-washable, low-odour alternative approved for incidental food contact. Q: What is Loctite 577 used for? Loctite 577 is a medium-strength thread sealant for parallel (BSP) threads used in hydraulic and pneumatic systems. It seals metal-to-metal pipe threads and fitting connections against fluid and gas leakage up to 150 bar, while remaining removable with hand tools for maintenance. Not a threadlocker — designed specifically for fluid-system thread sealing. Looking for anti-vibration mounts? Our anti-vibration mounts range covers the common sizes and brands. Looking for anti-seize compounds? Our anti-seize compounds range covers the common sizes and brands.
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