Anti-Seize Compound Guide: Types, Uses & Torque Reference

Types of Anti-Seize Compound — Quick Reference

Not all anti-seize compounds are interchangeable. The active metal or mineral filler determines temperature range, compatibility with base materials, and suitability for regulated environments.

What Is Anti-Seize Compound?

Anti-seize compound is a high-temperature assembly lubricant designed to prevent threaded fasteners, fittings, and mating surfaces from seizing, galling, and corroding — particularly in environments where heat, moisture, chemicals, or dissimilar metals accelerate the process. Where a threadlocker locks a fastener in place, anti-seize does the opposite: it ensures the fastener can be removed again after years of service.

Anti-seize handles metal-on-metal galling under load; for low-friction dry-film lubrication on plastic guides, rails and hinges, PTFE aerosol is the complementary product. See the Teflon (PTFE) spray guide for the dry-film application use cases.

The compound consists of metallic or mineral particles (copper flakes, nickel powder, graphite, or aluminium) suspended in a grease carrier. The metal particles form a sacrificial, low-friction barrier between mating surfaces — they embed into the surface asperities of the threads, reducing friction and preventing the micro-welding that causes galling and seizure.

Anti-seize is used across industrial maintenance, engineering, mining, construction, marine, food processing, and automotive workshops. Its correct application reduces maintenance costs significantly: seized fasteners mean broken studs, thread extraction, and in worst cases, scrapped components.

Types of Anti-Seize Compound

Not all anti-seize compounds are interchangeable. The active metal or mineral filler determines temperature range, compatibility with base materials, and suitability for regulated environments. Choosing the wrong type can accelerate corrosion rather than prevent it.

Copper Anti-Seize

Copper anti-seize is the most widely used industrial grade. It handles temperatures up to approximately 1,100°C and provides excellent corrosion protection on carbon steel and cast iron fasteners. It is the default choice for exhaust manifold studs, boiler fittings, heat exchanger bolts, flanged pipe joints, and general workshop assembly work.

One important caveat: copper is anodic relative to aluminium — applying copper anti-seize to aluminium threads can accelerate galvanic corrosion of the aluminium substrate in the presence of an electrolyte (moisture, salt, acid). For aluminium components, use aluminium-based or nickel-based anti-seize instead. Similarly, avoid copper anti-seize in chloride-rich environments (saltwater, some chemical plant environments) where copper ions can accelerate corrosion of stainless steel.

Nickel Anti-Seize

Nickel-based anti-seize offers the highest temperature resistance in the standard range (to ~1,300°C) and is the correct choice for stainless steel fasteners, particularly in petrochemical, refinery, and marine environments where chloride exposure is likely. Unlike copper, nickel does not create a meaningful galvanic couple with most engineering alloys, making it safer across a wider range of dissimilar metal combinations.

Nickel anti-seize is also the preferred grade where copper contamination is a concern — pharmaceutical processing, some clean-room environments, and applications where copper ions in process fluid would be problematic. Loctite 77164 (Nickel Anti-Seize), Molytec Nickel Anti-Seize, and CRC Nickel Anti-Seize are among the commonly available grades in Australia.

Aluminium Anti-Seize

The grey compound sold as "general purpose anti-seize" in most workshops is typically aluminium-based. It works adequately for moderate-temperature general assembly work, but it has critical limitations: its temperature ceiling of ~650°C means it is unsuitable for exhaust manifolds, turbocharger bolts, or any fastener exposed to sustained high heat. At elevated temperatures the aluminium carrier degrades and the compound loses its protective properties. Use copper or nickel grades for any heat-critical application.

Molybdenum Disulfide (MoS₂) Grease

Moly grease uses molybdenum disulfide as the solid lubricant filler, suspended in a lithium or calcium grease carrier. It provides exceptional load-carrying capacity under extreme pressure, making it the preferred product for splines, keyways, press fits, slewing ring gear teeth, and slow-speed high-load assemblies where conventional grease would be extruded. It is not a direct substitute for metallic anti-seize in threaded fastener applications — its temperature range is more limited and it performs poorly in sustained oxidising environments. For threaded fasteners, copper or nickel anti-seize remains the correct choice.

When to Use Anti-Seize

Anti-seize is warranted in any situation where the risk of seizure, galling, or corrosion-welding of a fastener is significant. The most common applications:

• Stainless steel fasteners. Stainless-to-stainless threads gall with almost predictable reliability under workshop conditions — the passive oxide layer on stainless is disrupted by friction, metal-to-metal contact occurs, and the threads weld together. Anti-seize is essential for any A2 or A4 stainless bolt, nut, or fitting that will need to be removed. See our Stainless Steel Fastener Grades Guide for full detail on galling prevention.
• High-temperature fasteners. Exhaust manifold studs and bolts, turbocharger mounting hardware, boiler flanges, heat exchanger tie bolts, and furnace door hinges are all routinely exposed to temperatures that drive corrosion and differential thermal expansion. Use copper anti-seize (up to ~1,100°C) or nickel anti-seize (up to ~1,300°C) depending on the application.
• Dissimilar metal assemblies. Where different metals are bolted together — steel bolts into aluminium castings, stainless fasteners into mild steel flanges, titanium bolts into steel — galvanic and crevice corrosion can lock fasteners permanently. Anti-seize applied to the threads provides a physical barrier that slows ionic transfer and prevents direct metal-to-metal contact.
• Underground or buried fasteners. Foundation bolts, inspection cover fixings, and any fastener exposed to soil, moisture, and biological activity needs protection. Copper or nickel anti-seize provides long-term corrosion protection that grease alone cannot.
• Pipe thread fittings in high-pressure / high-temperature systems. NPT, BSP, and other tapered pipe threads in steam lines, hydraulic circuits, and process pipework benefit from anti-seize to prevent galling on assembly and seizure during service.
• Marine and coastal environments. Salt air and saltwater accelerate galvanic corrosion dramatically. Use nickel-based anti-seize (avoid copper and graphite in direct saltwater contact — both can accelerate corrosion of surrounding metals).
• Heavy machinery maintenance cycles. Any fastener on mining, construction, or agricultural equipment that must be periodically removed for service — wear plate bolts, crusher liner studs, hydraulic fitting connections — should have anti-seize applied to guarantee future disassembly.

When NOT to Use Anti-Seize

Anti-seize is not universally appropriate. There are specific situations where its application causes problems rather than solving them:

• Where torque specifications assume dry or lightly oiled threads. Torque values in engineering specifications are calculated for a defined friction condition. Applying anti-seize to threads with a dry-torque specification delivers significantly higher clamping force than intended for a given torque value — with the risk of yielding or breaking the fastener, or damaging the mating surface. Either recalculate the torque (see below) or do not use anti-seize.
• Pre-coated fasteners. Many modern fasteners come with factory-applied dry-film lubricants, waxes, or anti-corrosion coatings. Adding anti-seize over the top changes the friction coefficient unpredictably. If a fastener is visibly coated or the specification says "do not add lubricant", follow it.
• Where vibration-resistance is critical. Anti-seize reduces friction, which reduces the fastener's resistance to vibratory loosening. For fasteners in vibrating assemblies — engine components, compressors, machinery subject to cyclic loading — use a threadlocker if vibration-resistance is required, not anti-seize. Never apply both to the same fastener: the combination is counterproductive and the torque relationship is undefined.
• Structural bolted connections specified for friction-grip. High-strength structural bolts in friction-type connections (HSFG, Gr 8.8 or 10.9 in structural steel) rely on friction between clamped surfaces to transfer load. Any lubricant on the faying surfaces destroys the designed slip coefficient and compromises the connection. Anti-seize must never be applied to structural bolts without engineer approval and re-assessment of the connection.
• Spark plugs in engines where the manufacturer specifies against it. This is discussed in detail in the FAQ section below.

Anti-Seize and Torque: The Critical Adjustment

This is the most commonly misunderstood aspect of anti-seize application. Anti-seize acts as a thread lubricant, reducing the friction coefficient (k-factor) between mating threads. Lower friction means that for any given applied torque, the resulting bolt preload (clamping force) is significantly higher than it would be with dry threads.

The relationship between torque (T), clamping force (F), bolt diameter (d), and friction coefficient (k) is:

T = k × F × d

For a dry carbon steel fastener, k ≈ 0.20. For an oiled fastener, k ≈ 0.15–0.18. For anti-seize applied, k ≈ 0.13–0.15 (varies by product — check the manufacturer’s data sheet for the specific k-factor).

Applying the same torque with anti-seize as you would to a dry fastener delivers approximately 25–35% higher clamping force. This can yield the bolt (permanently stretch it), strip the threads in a softer mating material, or crack a brittle casting.

The rule of thumb

Reduce the specified torque by 20–25% when applying anti-seize to a fastener torqued to a manufacturer’s dry or lightly lubricated specification. For precision-critical assemblies, obtain the k-factor from the anti-seize product data sheet and recalculate using the formula above.

Where torque is not critical — general maintenance work, threaded rod into plates, inspection covers, pipe flanges without pressure-specific torque requirements — the torque adjustment still applies as good practice, but the consequences of over-torque are less severe. Apply hand-snug first, then use feel and experience to judge the additional turn required.

For detailed torque reference tables by bolt grade, see our Bolt Grade Chart: Metric, Imperial & High Tensile Markings Guide.

Application Guide by Scenario

Is Anti-Seize the Same as Copper Grease?

In Australian workshops and trade stores, "copper grease" and "copper anti-seize" are used interchangeably, and for most purposes they refer to the same class of product. Both are copper-flake compounds in a grease carrier, designed to prevent galling and seizure.

Technically, some products marketed as "copper grease" have a lower metallic loading and are targeted at automotive brake component assembly (caliper pins, pad back-plates, slide pins) rather than threaded fastener protection. Products labelled "copper anti-seize compound" typically have higher metallic loading and are formulated for threaded fastener applications. In practice, the distinction matters more for brake caliper assembly (where you want a lubricant that stays pliable under cyclic heat) than for industrial fastener work.

When buying from a trade supplier rather than Bunnings or a automotive parts store, you’re more likely to be getting a proper industrial anti-seize compound with a defined temperature rating and k-factor on the data sheet.

How to Apply Anti-Seize Correctly

Anti-seize is effective when applied correctly and wasteful (or counterproductive) when applied incorrectly. The key principles:

1. Clean the threads. Remove existing rust, dirt, oil, and old compound before applying anti-seize. A wire brush or thread chaser clears the thread form; a rag removes loose contamination. Anti-seize applied over contaminated threads does not seat properly.
2. Apply sparingly. A thin, even coat on the bolt threads is sufficient — typically covering the first 3–5 threads that will be in contact. Over-applying is wasteful and the excess will be extruded off during tightening anyway. Use a brush, paddle, or the applicator cap supplied with the product.
3. Apply to the male thread only (in most cases). This reduces the risk of compound entering the assembly cavity or contaminating sealing surfaces. For blind holes, apply to the bolt rather than the hole.
4. Do not apply to both threads and under the bolt head unless you are accounting for both in the torque calculation. Lubrication under the bearing face of the bolt head changes the torque relationship further. For most workshop applications, apply to threads only and reduce torque by 20–25%.
5. Apply the torque correction. See the table above. This step is non-negotiable for any safety-critical or manufacturer-specified torque value.
6. Do not use anti-seize on the thread sealing portion of BSPT or NPT pipe fittings if a separate thread sealant is specified. On pipe threads without a sealant requirement (dry-seal threads), anti-seize can provide light sealing function as well as anti-gall protection.

Anti-Seize vs Threadlocker: Never Both

This is a common mistake in workshop practice. Anti-seize and threadlockers (such as Loctite 243, 263, or 277) are fundamentally opposing products — one prevents removal, the other ensures it. Applying both to the same fastener produces unpredictable results: the anti-seize typically prevents the threadlocker resin from fully contacting the thread surfaces, reducing locking strength significantly, while the torque relationship is undefined.

Decide which property you need:

• If you need vibration resistance — use threadlocker (Loctite 243 for medium strength, 263 or 277 for high strength)
• If you need future disassembly in high-heat or corrosive conditions — use anti-seize
• If you need both (vibration resistance AND disassembly) — select a fastener with an appropriate prevailing torque nut (nyloc, all-metal locking nut), use a star washer, or re-engineer the joint

For detailed threadlocker selection, see our Loctite Industrial Selection Guide, which also covers the Loctite anti-seize product range (LB 8008, LB 8150, 77164).

Frequently Asked Questions

What is the difference between copper, nickel, and aluminium anti-seize?

The main differences are temperature range, metal compatibility, and environmental suitability. Copper anti-seize handles up to ~1,100°C and is the standard industrial grade for steel-on-steel, exhaust hardware, and pipe fittings — but should not be used on aluminium threads or in marine environments. Nickel anti-seize handles up to ~1,300°C, is compatible with stainless steel and dissimilar metal assemblies, and is safer in chloride/marine environments. Aluminium (grey) anti-seize is general purpose but limited to ~650°C and is unsuitable for high-heat applications. When in doubt between copper and nickel, nickel is the safer choice across a wider range of applications.

Does anti-seize reduce the torque I need to apply?

Yes — significantly. Anti-seize acts as a thread lubricant, lowering the friction coefficient (k-factor) between mating threads. Applying the same torque to an anti-seize-coated fastener as you would to a dry one delivers approximately 25–35% higher clamping force. To achieve the correct preload, reduce the specified torque by 20–25% when anti-seize is applied. For precision-critical assemblies, use the anti-seize product’s published k-factor in the formula T = k × F × d.

Can I use copper anti-seize on aluminium threads?

No — this is a common and potentially damaging mistake. Copper is electrochemically active relative to aluminium. In the presence of moisture or an electrolyte, copper ions can accelerate galvanic corrosion of the aluminium substrate. For steel bolts threaded into aluminium components (common on engine blocks, pump housings, and fabricated aluminium structures), use nickel-based or aluminium-based anti-seize instead.

Should I use anti-seize on spark plugs?

It depends on the plug type and engine specification. For spark plugs with bare steel threads (common in older cast iron heads), a small amount of copper anti-seize helps prevent the plug from seizing in the head over time. However, many modern spark plugs come with a factory-applied nickel plating or dry-film coating on the threads — adding anti-seize to a pre-coated plug is unnecessary and changes the torque relationship unpredictably. OEM recommendations vary: NGK and Denso typically advise against additional anti-seize on their coated plugs. If the plug has a silver or grey finish on the threads, check the manufacturer specification before applying. Always reduce the specified torque by the appropriate factor if anti-seize is used.

Can I use anti-seize and Loctite threadlocker on the same fastener?

No. Anti-seize and threadlockers are opposing products. Anti-seize prevents metal-to-metal contact that threadlocker resin needs to cure properly against — applying both significantly reduces locking strength while also creating an undefined torque relationship. Choose one or the other based on whether you need vibration resistance (threadlocker) or guaranteed future disassembly (anti-seize).

When should I NOT use anti-seize?

Anti-seize should not be used on: (1) fasteners torqued to a dry-torque specification if you cannot apply the appropriate torque reduction; (2) pre-coated fasteners where the manufacturer specifies no lubricant; (3) structural friction-grip bolted connections; (4) wheel lug nuts and wheel studs on most vehicles (OEMs specify dry torque — anti-seize increases preload and can cause loose wheels or shear at the correct torque); (5) any fastener being secured with a threadlocker simultaneously.

Is anti-seize the same as copper grease?

In Australian trade practice, they are largely the same product. Both refer to a copper-flake compound in a grease carrier that prevents galling and corrosion on threaded fasteners and assembly surfaces. Products specifically labelled “anti-seize compound” from industrial suppliers typically have a higher metallic loading and come with published temperature ratings and k-factor data. “Copper grease” from automotive stores may have lighter metallic loading and be oriented toward brake component assembly rather than high-temperature fastener work. For critical industrial applications, buy a product with a published data sheet.

What temperature can anti-seize handle?

This varies significantly by type: aluminium (grey) grade ~650°C; copper-based ~1,100°C; nickel-based ~1,300°C. For context, an exhaust manifold on a petrol engine reaches approximately 750–900°C under sustained load, which is within copper range but requires nickel for diesel turbocharged engines running hotter. Always check the product data sheet for the specific grade you are using — maximum temperature ratings differ between manufacturers even within the same compound type.

What is food grade anti-seize and when do I need it?

Food grade anti-seize is formulated without metallic fillers that could contaminate food or pharmaceutical products. It uses a carrier that is approved for incidental food contact under NSF H1 registration (or equivalent), with active ingredients such as PTFE or calcium compounds. It is required in food processing, brewing, dairy, and pharmaceutical environments wherever a fastener, fitting, or mechanical component could have incidental contact with the product stream. NSF H1 certification means the product is acceptable for use in areas where the lubricant may contact food in small quantities that cannot be avoided. NSF H2 is for areas with no possible food contact. Temperature range is typically limited to ~200–260°C — it is not a substitute for copper or nickel in high-heat applications.

How do I apply anti-seize correctly?

Apply a thin, even coat to the first 3–5 engaged threads of the male fastener using a brush or the product’s applicator cap. Clean the threads first to remove contamination. Apply to the male thread only in most cases; applying under the bolt head as well changes the torque calculation further. Do not over-apply — excess compound is extruded off during tightening and serves no useful purpose. Reduce applied torque by 20–25% from the dry specification (or use the product k-factor for precision work).

Why does stainless steel seize without anti-seize?

Stainless steel has a passive chromium oxide layer on its surface that provides corrosion resistance. Under the friction and pressure of thread engagement, this oxide layer breaks down locally. The exposed bare stainless metal on both mating surfaces immediately re-oxidises and micro-welds together — a process called galling. Once galling starts it is self-reinforcing: the micro-welds shear and re-weld with each small movement until the fastener is completely seized. Anti-seize prevents the initial metal-to-metal contact by keeping a thin barrier of metallic particles between the thread surfaces throughout tightening.

What anti-seize should I use for exhaust manifold bolts?

Use copper-based or nickel-based anti-seize — not the grey aluminium grade. Copper anti-seize handles up to ~1,100°C and is suitable for most petrol engine exhaust applications. Nickel anti-seize (to ~1,300°C) is preferred for diesel turbocharged engines, high-performance applications, and any manifold that sees sustained extreme heat. The aluminium-base grey compound should never be used on exhaust hardware — it degrades at elevated temperature and loses its protective properties at the temperatures that matter most.

What is molybdenum disulfide grease used for?

MoS₂ (moly) grease is primarily used for high-load, slow-speed, sliding assemblies: splines, keyways, press-fit components, slewing ring gear faces, and CV joint internal components. It provides extreme-pressure lubrication that standard greases cannot match under heavy compressive loads. It is not a direct substitute for metallic anti-seize on threaded fasteners — copper or nickel anti-seize remains the correct choice for threaded joints in high-temperature or corrosive environments. MoS₂ is also used as a coating on some fasteners (typically high-strength structural bolts) to produce a consistent, low friction coefficient — in this case no additional anti-seize is needed.