Epoxy adhesive is one of the most versatile bonding and repair products in a tradesperson's or maintenance engineer's toolkit. It bonds metal, concrete, ceramic, timber, and most engineering plastics with structural strength and solid resistance to chemicals, heat, and moisture. But “epoxy” covers two very different products: liquid 2-part epoxy adhesive for surface bonding, and epoxy putty for gap-filling, shaping, and component repair. Choosing the wrong type — or applying it incorrectly — is the single most common reason epoxy fails.
This guide covers both liquid and putty formats: what they are, when to use each, how to apply them correctly, what epoxy won't stick to (more important than most people realise), and which products AIMS Industrial stocks for Australian tradespeople and maintenance teams. Products from Loctite and Devcon are covered throughout with direct links where relevant.
What Is Epoxy Adhesive?
Epoxy adhesive is a two-component structural adhesive consisting of a resin (Part A) and a hardener (Part B). When mixed, they undergo an exothermic chemical reaction — producing heat as the compound cures into a rigid, cross-linked polymer. This is fundamentally different from contact adhesives or cyanoacrylate (super glue), which rely on physical surface contact or simple chemical reactions. Epoxy forms a structural bond — once cured, it becomes a load-bearing part of the assembly, resisting water, chemicals, heat, and mechanical loading far better than most other adhesive types.
Epoxy products come in several physical formats:
- Dual-syringe packs: Two components in side-by-side barrels. A static mixer nozzle ensures the correct ratio and thorough blending automatically. Clean, accurate, minimal waste. Ideal for small-to-medium jobs. Examples: Loctite 3801 Epoxy Adhesive Syringe and Loctite 5 Minute Epoxy.
- Separate containers: Part A and Part B in individual tins or bottles. Requires manual measurement per the product's technical data sheet. Common in larger industrial volumes. Example: Devcon Plastic Steel Liquid B.
- Putty sticks or two-layer packs: The two components are moulded together as concentric cylinders or distinct-coloured layers. Activated by kneading — no measuring or mixer nozzles needed. Examples: Loctite 3463 Metal Magic Steel and Devcon Aluminium Putty F.
Browse the full epoxy adhesive range and epoxy repair compound range at AIMS Industrial.
Epoxy Adhesive vs Epoxy Putty — When to Use Each
Both are 2-part epoxy systems, but they're designed for different jobs and are not interchangeable.
| Property | Liquid Epoxy Adhesive | Epoxy Putty |
|---|---|---|
| Physical form | Liquid to paste consistency | Firm, mouldable solid |
| Primary purpose | Bond two surfaces together | Fill gaps, rebuild missing material |
| Bond line | Thin (typically <1mm) | Thick — fills voids up to several centimetres |
| Application method | Apply to surface, bring parts together, clamp | Press into void, shape by hand |
| Machinable after cure? | Generally no (brittle in thin layer) | Yes — can be drilled, tapped, filed, painted |
| Gap-filling ability | Poor (sags or cracks if gap >1mm) | Excellent |
| Typical working time | 5–60 min depending on grade | 15–30 min |
Use liquid epoxy adhesive when you're joining two surfaces that fit together well — bonding flanges, setting anchor bolts, attaching brackets, structural panel repair, bonding metal to concrete.
Use epoxy putty when there's a hole, crack, cavity, or missing section to fill and rebuild — sealing a pipe leak, rebuilding corroded threads, filling a casting defect, underwater repair, wear surface rebuild.
If you're not sure which format suits your job, our team is happy to help. Get in touch or call (02) 9773 0122 — getting this right before you buy saves time and avoids the frustration of a failed repair.
Epoxy Adhesive vs Epoxy Resin — Not the Same Product
A very common source of confusion. Epoxy resin (casting resin, coating resin, table-top resin) is also a 2-part system — but it's formulated for an entirely different purpose. Casting and coating resins are designed to self-level, cure optically clear, and coat surfaces. They are not structural adhesives.
Key differences:
- Viscosity: Casting resins are watery to honey-like. Structural epoxy adhesives are paste to putty consistency.
- Purpose: Casting resin encapsulates or coats surfaces. Epoxy adhesive bonds or repairs under mechanical load.
- Fillers: Structural epoxy adhesives contain mineral or metal fillers for strength and gap-filling. Casting resins are unfilled and optically clear.
- Load capacity: Casting resin is not formulated for load-bearing bonds and will crack or peel under stress.
- Pot life: Many casting resins have very long working times designed for large pours — not appropriate for adhesive applications.
If a product is marketed for art, jewellery, river tables, or floor coatings — it's casting or coating resin, not a structural adhesive. The Loctite and Devcon products covered in this guide are formulated specifically for bonding, repair, and industrial maintenance.
What Epoxy Won't Bond To
Understanding what epoxy won't stick to is just as important as knowing what it will. This is consistently the most-searched question about epoxy for good reason — using the wrong adhesive on the wrong substrate wastes time and creates a false sense of security in a structural repair.
Surfaces epoxy generally won't bond reliably to:
- Polyethylene (PE) and polypropylene (PP): Low surface energy plastics. Epoxy may appear to stick initially but adhesion is poor and fails under load or after ageing. Identified by the moulded codes PE, HDPE, LDPE, or PP — extremely common in containers, pipe fittings, tanks, and packaging materials.
- PTFE / Teflon: The definitive non-stick material. Nothing adheres reliably to PTFE without specialised surface treatment (sodium etching, plasma treatment). Epoxy is no exception.
- Silicone: Very low surface energy material. Epoxy won't bond to cured silicone. In workshop environments, silicone contamination (from release agents, gasket compounds, or aerosol lubricants) on otherwise bondable surfaces will also prevent adhesion. Degrease thoroughly if silicone contamination is suspected.
- Wet or damp surfaces: Water between the substrate and epoxy prevents proper adhesion. The surface must be completely dry before application — even condensation is enough to compromise a bond.
- Oily or greasy surfaces: Oil contamination is the number one cause of epoxy bond failure in workshop environments. Even fingerprints have enough oil to reduce bond strength significantly. Always degrease immediately before application.
- Smooth, non-abraded surfaces: Even on bondable materials, a mirror-smooth surface gives epoxy no mechanical keying. Abrasion is not optional — it must be done correctly.
- Highly flexible or rubbery substrates: Cured epoxy is rigid. Bonding to rubber or highly flexible plastics will stress-crack the bond line as the substrate flexes. Use a flexible adhesive (polyurethane, MS polymer) for flexible-substrate bonds.
If your substrate falls into any of these categories, call us before you buy — (02) 9773 0122. There are specific primer systems and alternative adhesive technologies for challenging substrates, and we can point you to the right solution.
Epoxy Types by Application
Structural / General-Purpose Liquid Epoxy
The workhorse format for industrial and trade bonding. Dual-syringe packs with a static mixer nozzle give accurate, well-blended mix through the nozzle without manual measuring. Typical working time is 30–60 minutes; functional strength in 8–24 hours. Bonds metal, concrete, ceramic, timber, glass, and most engineering plastics. The Loctite 3801 Epoxy Adhesive Syringe (29.5ml) is the stocked structural liquid epoxy at AIMS — suited to anchor bolt setting, panel repair, bracket bonding, and general maintenance bonding applications.
5-Minute Fast-Cure Epoxy
Fast-cure formulation with a 4–5 minute working time and functional strength in approximately 1 hour. Useful where speed matters more than maximum strength — positioning components before secondary fastening, light repairs where waiting isn't practical, field maintenance under time pressure. Tensile strength is typically lower than slow-cure structural grades. The Loctite 5 Minute Epoxy (14ml) is the stocked fast-cure option.
Metal-Filled Epoxy Putty (Steel)
Contains steel or iron powder to give the cured compound metal-like hardness. The putty stick activates by kneading — no equipment required. Used for emergency metal repair, rebuilding stripped threads (apply, cure, re-tap), filling voids in steel castings, sealing cracks in housings, and pipe repair. The Loctite 3463 Metal Magic Steel putty stick can be drilled, filed, tapped, and painted after full cure. J-B Weld is a widely recognised brand in this category across the Australian market — the Loctite and Devcon equivalents represent the industrial-grade comparable product.
Aluminium-Filled Epoxy Putty
Same format as steel-filled putty, with aluminium powder — lighter, better thermal properties, and suited to aluminium alloy repair. The Devcon Aluminium-Filled Epoxy Putty (F) 500g is the maintenance-standard choice for aluminium castings, crankcases, gearbox housings, and aluminium structural components. After full cure (24 hours), it machines similarly to cast aluminium — drill, tap, file, sand, paint. Frequently used for permanent repair of castings that would otherwise require welding or replacement.
Metal-Filled Liquid Epoxy Paste
A high-viscosity paste — thicker than a syringe adhesive, thinner than putty — for rebuilding worn or corroded metal surfaces, shaft repair, pump housing rebuild, and surface restoration. The Devcon Plastic Steel Liquid (B) 500g is a steel-particle-filled 2-part product mixed manually from two containers in a 2:1 ratio (A:B) by volume. Applied by brush, spatula, or trowel. Used in mining, manufacturing, and heavy maintenance for rebuilding worn bearing housings, filling corrosion pitting on shafts, and repairing cracked castings. After full cure, Devcon Plastic Steel can be machined to tight tolerances.
Ceramic / Wear-Resistant Epoxy
Contains ceramic filler (silicon carbide, aluminium oxide) for exceptional abrasion and erosion resistance. Applied to pump housings, impellers, wear plates, piping bends, and surfaces subject to slurry, grit, or particle impingement. These compounds trade some mechanical strength for surface hardness and wear life. Belzona 1321 Ceramic S-Metal is the industry benchmark — widely specified in petrochemical, mining, and power generation. Not stocked by AIMS, but the reference standard when specifying for high-wear environments. Contact us for availability of ceramic-grade products.
Marine and Underwater Epoxy
Formulated to cure in contact with water or while submerged — the material displaces water from the repair surface during application. Used for hull repairs, pool repairs, burst pipe emergency patching, and any application where drying the surface before repair isn't possible. Important distinction: all cured standard epoxy is water-resistant once cured, but underwater epoxy cures actively in water. If you need to repair something submerged or in a live-wet environment, the product must specifically state “cures underwater” — not just “waterproof when cured.”
Plumber's Epoxy Putty
A specific variant of epoxy putty for plumbing repair — sealing leaking joints, pinhole leaks in copper and galvanised pipe, and fitting repair. Some grades carry NSF or WRAS certification for use on potable water systems — always verify the specific product's approvals before using on drinking water lines. Suitable as an emergency or temporary repair; consult a licensed plumber for permanent high-pressure pipework repairs.
How to Choose the Right Epoxy
| Your application | Recommended type | AIMS stocked product |
|---|---|---|
| Bonding two metal or mixed surfaces | Structural liquid epoxy | Loctite 3801 |
| Quick repair, needs strength in 1hr | 5-minute epoxy | Loctite 5 Min Epoxy |
| Repairing a steel component (crack, stripped thread, void) | Steel-filled epoxy putty | Loctite 3463 Metal Magic |
| Repairing aluminium castings or housings | Aluminium-filled epoxy putty | Devcon Al Putty F |
| Rebuilding worn metal surfaces (shaft, bearing housing) | Metal-filled liquid epoxy paste | Devcon Plastic Steel Liquid B |
| Wear-resistant surface rebuild (slurry, grit, abrasion) | Ceramic-filled epoxy | Contact us |
| Submerged or wet surface repair | Underwater-rated epoxy putty | Contact us |
| Potable water pipe or fitting repair | Approved plumber's putty | Contact us |
Epoxy product selection is one area where getting advice before you buy genuinely pays off — the range of formulations, fillers, and cure profiles is wide, and the wrong choice usually means repeating the job. Our team is here to help. Contact AIMS Industrial with your application details — substrate, load, operating temperature, environment — or call us on (02) 9773 0122. We work with maintenance engineers and trade teams across Australia every day.
How to Use Liquid Epoxy Adhesive Correctly
Surface preparation contributes more to bond strength than the adhesive choice itself. Most epoxy failures trace back to inadequate preparation, not the product.
Step 1 — Degrease
Wipe both bonding surfaces with isopropyl alcohol (IPA) or acetone using a clean, lint-free cloth. Repeat until the cloth comes away clean. Any oil, grease, release agent, or fingerprints will prevent bonding. This step is non-negotiable.
Step 2 — Abrade
Roughen the bonding surface with 80–150 grit abrasive. On metal, work in a cross-hatch pattern to maximise surface area. On concrete or masonry, wire brush or angle grind to remove laitance (the weak surface layer). The goal is a uniformly textured surface — mechanical abrasion gives the epoxy physical keys to grip. Do not skip this step even on metal that looks clean.
Step 3 — Degrease again
Wipe down again with IPA after abrading. Abrasion generates fine metallic or mineral dust that must be removed before bonding. Allow to dry completely before applying epoxy.
Step 4 — Mix
For syringe packs: attach the static mixer nozzle. Dispense a small amount to waste (approximately 1cm of bead) to ensure the nozzle is fully primed before your working mix. The nozzle handles ratio and mixing automatically — do not attempt to mix separately on a board. For separate-container systems: measure Part A and Part B by volume to the product's specified ratio. Mix thoroughly with a clean implement for 3–4 minutes until the colour is completely uniform. Incomplete mixing produces an under-strength, tacky, or rubbery cure. Work at 21–29°C for best results.
Step 5 — Apply and clamp
Apply epoxy to one of the two surfaces. Bring surfaces together and apply firm, even clamping pressure. Remove squeeze-out before it cures. Do not disturb the joint during the working time.
Step 6 — Cure
Leave the joint undisturbed for the product's specified cure period. Functional loading can generally begin after 8–24 hours; full rated strength takes 3–7 days at 20–25°C. Do not apply heat to accelerate cure in the first few hours unless the product's TDS specifically supports this — heat during early cure can cause stress cracking.
Temperature note: Epoxy cure slows significantly below 15°C and may fail to reach full strength below 10°C. If working in cold conditions, warm the substrate to at least 15°C before application and maintain temperature through the initial cure period.
How to Use Epoxy Putty Correctly
Putty is simpler to apply than liquid epoxy — no measuring, no nozzles — but technique still determines whether you get a reliable repair.
Step 1 — Prepare the surface
Same principle as liquid epoxy: degrease and abrade the substrate around the repair area. Even though putty is filling a void, the surrounding material must be clean and roughened for the putty to bond to the substrate edges. On corroded metal, remove all loose material and scale before applying putty.
Step 2 — Cut the putty
For putty sticks, cut the required length with a sharp knife. The two components are visually distinct (typically different colours — an outer shell and a contrasting core). A clean cross-section should show both colours. If the cut end shows only one colour, cut a little further to expose both components.
Step 3 — Knead
Work the putty firmly between your fingers for 2–3 minutes until the colour is completely uniform with no streaks or marbling. Wear nitrile gloves — epoxy hardeners are skin sensitisers (see Safety section below). Incomplete kneading means incomplete mixing, which means a weak or rubbery cure rather than full strength.
Step 4 — Apply and shape
Press the kneaded putty firmly into the repair area. Force it into cracks and crevices. For pipe leaks, wrap firmly around the pipe and compress to ensure full contact. Smooth the surface with a gloved finger or wet spatula — dampening with water or IPA prevents the putty from sticking to your tool during shaping. Work quickly and complete shaping before working time expires.
Step 5 — Cure and machine
Most putties are firm within 30–60 minutes, machinable in 2–4 hours, and at full strength in 24 hours. After full cure, metal-filled putties (Devcon Aluminium, Loctite 3463) can be drilled, tapped, filed, sanded, and painted. They machine similarly to soft aluminium or mild steel depending on filler type. For precision machining, wait for full 24-hour cure rather than the minimum machinable time.
Cure Times and Temperature Reference
| Stage | 5-Minute Epoxy | Standard Liquid Epoxy | Epoxy Putty |
|---|---|---|---|
| Working time | 4–5 min | 30–60 min | 15–30 min |
| Touch dry / firm | 15–30 min | 2–4 hr | 30–60 min |
| Functional (handle the joint) | ~1 hr | 8–24 hr | 2–4 hr |
| Machinable (putty only) | — | — | 2–4 hr |
| Full rated strength | 24 hr | 3–7 days | 24 hr |
Temperature effects:
- Below 10°C: Cure may stall or produce a weak bond. Warm substrate to at least 15°C.
- 10–15°C: Cure proceeds but slowly — extend functional strength timeline by 50–100%.
- 21–29°C: Optimal range. Use published cure times.
- Above 35°C: Working time shortens. Have everything prepared before mixing.
- Post-cure temperature resistance: Most industrial epoxies withstand 120°C+ once fully cured. Devcon Titanium Putty is rated to 177°C. Always verify against the specific product's TDS for high-temperature applications.
Limitations — When Not to Use Epoxy
Epoxy is versatile, but it's not the right solution for every application.
- Vibration fatigue: Cured epoxy is rigid and relatively brittle. In high-vibration environments — rotating machinery, compressor mounts, vehicle chassis — cyclic loading can cause fatigue cracking at the bond line over time. Consider polyurethane or MS polymer adhesives for vibration-exposed joints, or use epoxy in combination with mechanical fastening.
- Impact loading: Epoxy has good compressive and tensile strength but poor impact (peel) resistance. A joint subject to sudden shock loading may fail at the bond line even if the static load is within rating. Use mechanical fasteners as the primary load path where impact is a factor.
- UV exposure: Most standard epoxies yellow and degrade with prolonged UV exposure. Exterior applications require a UV-stable topcoat over the cured epoxy to prevent surface breakdown.
- Large unsupported gaps in liquid format: Liquid epoxy in a thin, close-fitting bond line is strong. If used to fill a large gap (>2mm) unsupported, it can crack as cure shrinkage occurs. Use putty for gap-filling applications.
- Welding proximity: If subsequent welding is required near an epoxied joint, complete all welding first and allow the workpiece to cool before applying epoxy. Heat from welding can damage partially or fully cured epoxy, causing the repair to fail.
- Continuous solvent immersion: Epoxy is chemically resistant to many substances, but prolonged immersion in strong solvents (ketones, chlorinated solvents) can cause swelling and strength loss. Always check the product's chemical resistance data for the specific service environment.
Brand Guide — Epoxy Products at AIMS and in the Market
Devcon — Industrial Maintenance Repair (Stocked at AIMS)
Devcon is one of the most widely used brands for maintenance and repair epoxy in Australian industry. The range spans metal-filled putties, liquid pastes, ceramic compounds, and high-temperature variants. Two Devcon products are stocked at AIMS:
- Devcon Plastic Steel Liquid (B) — 500g: Steel-particle-filled 2-part liquid paste. Mixed 2:1 by volume (A:B). Used for rebuilding worn bearing housings, filling corrosion pitting on shafts, emergency repair of cracked castings, and pump component rebuild. Machinable after full cure. Widely used in mining, manufacturing, and heavy maintenance.
- Devcon Aluminium-Filled Epoxy Putty (F) — 500g: Aluminium-powder-filled 2-part putty. Mixed 2:1 by volume. For aluminium casting repair, housing rebuild, and corrosion damage to aluminium structures. Machinable, lightweight, and visually compatible with aluminium alloys after finishing.
Devcon's broader range includes Titanium Putty (rated to 177°C), Wear-Guard (ceramic-filled, for abrasion protection), Underwater Putty, and Brushable Ceramic. Contact us for availability on products beyond the standard stocked range.
Loctite — Epoxy Adhesive and Metal Repair (Stocked at AIMS)
Loctite's epoxy range covers structural bonding and fast-cure applications in convenient syringe format, plus a metal-filled putty stick for field repairs. Three Loctite epoxy products are available at AIMS:
- Loctite 3801 Epoxy Adhesive Syringe — 29.5ml: 2-component structural epoxy in dual-syringe format with static mixer nozzle. Clean, accurate application. Suited to industrial bonding, anchor setting, bracket attachment, and maintenance repair where a precisely mixed application is needed.
- Loctite 5 Minute Epoxy — 14ml: Fast-cure 2-part epoxy. Working time approximately 5 minutes; functional in about 1 hour. For light to medium repairs where cure speed is the priority over maximum load capacity.
- Loctite 3463 Metal Magic Steel (EA 3463): Metal-filled epoxy putty stick for on-the-spot steel repairs. Kneads active in 1–2 minutes, workable for approximately 20 minutes, machinable in 2–4 hours. For emergency pipeline repair, stripped thread rebuild, and component patching in the field.
Araldite — Consumer to Light Industrial
Araldite (Huntsman) is one of the best-recognised epoxy brands in Australia — widely available in hardware stores and familiar to most tradespeople. Araldite Rapid and Araldite Standard are the common consumer formats. Solid general-purpose performers for light to medium loads. Not stocked by AIMS — the Loctite and Devcon products above represent the equivalent industrial-grade options at commercial volumes.
Belzona — Premium Industrial Specification
Belzona is the premium specification-grade epoxy system used in heavy industry — petrochemical, mining, power generation, and marine. Belzona 1111 Super Metal and 1321 Ceramic S-Metal are the best-known products, widely specified where downtime cost justifies the price premium. Available in Australia via Rezitech. Belzona is not stocked by AIMS but is the relevant reference when a maintenance engineer specifies a ceramic-grade or premium metal-repair compound.
Not sure which product fits your application?
Epoxy selection — format, filler type, cure speed, temperature rating — has a real impact on repair quality and longevity. Our team works with Australian maintenance engineers and trade teams every day and can help you choose the right product for your specific job. Contact AIMS Industrial or call (02) 9773 0122. We'll ask the right questions and point you to the right product.
Safety and Storage
Skin sensitisation — the most important safety point
Epoxy hardeners (Part B, amine-based) are classified as skin sensitisers. Repeated skin contact — even without obvious irritation — can lead to epoxy sensitisation: a permanent allergic condition. Once sensitised, even trace exposure can cause a severe reaction and may make it impossible to continue working with epoxy. Always wear nitrile gloves when handling uncured epoxy. This is not optional and not negotiable.
Eye protection
Wear safety glasses or goggles when working with liquid epoxy. Splashing Part B hardener can cause serious eye damage. Syringe formats reduce splash risk compared to open-container mixing, but eye protection is still required.
Exothermic heat
Mixing large volumes of epoxy generates significant heat. In confined containers or enclosed spaces, this can reach temperatures sufficient to cause burns or start a fire. Always mix in open, flat-bottomed containers. For large-volume jobs, mix in batches of 200ml or less rather than attempting to mix the full volume at once.
Ventilation
Work in well-ventilated areas. Amine hardeners produce detectable odours and should not be inhaled in confined spaces. For confined space work, ensure adequate extraction and follow your site's confined space entry procedure.
Storage
Store Part A and Part B separately, tightly sealed, at 15–25°C, away from heat sources and direct sunlight. Do not freeze. Shelf life is typically 12–24 months from manufacture date — check the product's TDS. For syringe packs, leave the static mixer nozzle attached between uses — it seals the cartridge against air ingress.
Disposal
Fully cured epoxy is chemically inert and can be disposed of as general solid waste in most Australian jurisdictions. Uncured epoxy (particularly the hardener) is classified as hazardous waste — contact your local council for disposal requirements. Never pour uncured epoxy or hardener down drains or into soil.
Frequently Asked Questions — Epoxy Adhesive
What is epoxy adhesive used for?
Epoxy adhesive is used for structural bonding, component repair, and surface rebuilding across a wide range of materials — metal, concrete, ceramic, timber, and most engineering plastics. Common applications include bonding flanges and brackets, setting anchor bolts, repairing cracked housings, rebuilding worn shafts, sealing pipe leaks, and filling casting defects. Format choice (liquid adhesive or putty) depends on whether you're bonding two surfaces together or filling and rebuilding missing material.
What will epoxy not stick to?
Epoxy won't bond reliably to polyethylene (PE/HDPE), polypropylene (PP), PTFE/Teflon, silicone, wet or damp surfaces, oily or greasy surfaces, or highly flexible rubber substrates. Of these, oil contamination and PE/PP plastics are the most commonly encountered in workshop environments. Even on bondable materials, a smooth un-abraded surface will produce a weak bond. Always degrease and abrade before application.
Is epoxy the strongest adhesive available?
Epoxy is among the strongest structural adhesives for metal-to-metal and metal-to-concrete bonds, particularly in shear and compression. For very small, close-fitting bonds, cyanoacrylate (super glue) can achieve higher tensile strength per mm². However, epoxy significantly outperforms cyanoacrylate in gap-bridging, chemical resistance, temperature resistance, and long-term durability under load. For most industrial maintenance and trade repair applications, structural epoxy delivers the best combination of strength, versatility, and service life.
What's the difference between epoxy adhesive and epoxy resin?
Epoxy adhesive is a structural bonding and repair product — formulated with mineral or metal fillers, paste to putty viscosity, designed to bond surfaces and carry mechanical load. Epoxy resin (casting or coating resin) is formulated to self-level, cure optically clear, and coat surfaces. It's designed for encapsulation, artwork, and coatings — not structural bonding under load. Using casting resin as a structural adhesive will typically result in failure. The Loctite and Devcon products stocked by AIMS are structural adhesives, not casting resins.
What's the difference between 1-part and 2-part epoxy?
1-part (single-component) epoxy adhesives are pre-mixed formulations that require heat to cure — typically oven temperatures of 120–180°C. They are used primarily in electronics and aerospace manufacturing and are not common in industrial maintenance or trade repair. Almost all epoxy adhesives used in trade, field repair, and industrial maintenance are 2-part systems — the resin and hardener are mixed immediately before use, initiating the curing reaction at ambient temperature without any need for heat.
How long does epoxy take to fully cure?
Full cure typically takes 3–7 days at 20–25°C for standard structural liquid epoxy. Most products achieve functional strength sufficient to handle the joint and apply moderate loads within 8–24 hours. 5-minute epoxy is functional in about 1 hour. Epoxy putty is machinable in 2–4 hours and at full strength in 24 hours. Cold temperatures slow cure significantly — below 10°C, many formulations will cure incompletely or not at all.
Can I use epoxy in cold weather?
Standard epoxy will cure above 10°C but slowly, and strength development is impaired. Below 10°C, most formulations will cure incompletely. If working in cold conditions, warm the substrate to at least 15°C before application — a heat gun is effective for localised substrate warming — and protect the assembly from temperature drop during the initial cure period. Some low-temperature formulations are available for extreme cold environments — contact us for advice if this is a requirement.
Does epoxy putty really work?
Yes — when properly applied to a correctly prepared surface, quality metal-filled epoxy putty (Devcon, Loctite 3463) produces a repair that can be machined, tapped, and loaded in service. These products are trusted in industrial maintenance environments to repair production equipment, not just cosmetic applications. The most common cause of putty repair failure is inadequate surface preparation — specifically, oil contamination or failure to abrade. Prepare the surface correctly and the repair is genuinely durable.
What is the strongest epoxy for metal-to-metal bonding?
For maximum metal-to-metal bond strength, a slow-cure structural epoxy (30–60 minute working time) typically achieves higher tensile and shear strength than 5-minute grades — the shorter cure time comes at a cost to ultimate strength. The Loctite 3801 is the stocked structural option. Surface preparation is the dominant factor — the same product on a properly prepared surface versus a poorly prepared one can achieve double the bond strength. J-B Weld is a well-known name in this category in Australia; Loctite and Devcon are the industrial-specification equivalents.
What are the disadvantages of epoxy adhesive?
The main limitations are: (1) Brittle once cured — poor impact and peel resistance. (2) Rigid — unsuitable for joints that flex or vibrate cyclically without additional mechanical support. (3) Mix-sensitive — incorrect ratio or incomplete mixing produces an under-strength or rubbery cure. (4) Limited pot life after mixing — you must complete application within working time. (5) UV degradation — yellows and weakens outdoors without UV-resistant topcoating. (6) Won't bond certain plastics (PE, PP, PTFE, silicone). (7) Hardener is a skin sensitiser — requires proper PPE at every use.
Can I drill or tap cured epoxy putty?
Yes — this is one of the main advantages of metal-filled epoxy putties. Devcon Aluminium Putty and Loctite 3463 Metal Magic are specifically designed to be machined after cure. They can be drilled with standard HSS drill bits, tapped with standard thread taps, filed, sanded, and painted. Best machining results are achieved after full 24-hour cure rather than at the minimum machinable time of 2–4 hours. Use sharp tooling and light cuts — the material is hard and will blunt dull cutters faster than mild steel.
Can epoxy adhesive be used on concrete?
Yes — epoxy bonds well to concrete and masonry when the surface is clean, dry, and correctly prepared. Remove laitance (the weak surface layer on concrete) by wire brushing, grinding, or acid etching before application. Degrease with IPA. Allow to dry completely — residual moisture compromises adhesion to concrete significantly. Structural epoxy is commonly used for anchor bolt setting in concrete, concrete crack injection, and bonding metal fixtures or plates to concrete substrates.
What is metal epoxy putty used for?
Metal-filled epoxy putty is used for: repairing cracks and voids in cast metal components (housings, gearboxes, engine blocks), rebuilding stripped or corroded threads, filling casting defects prior to machining, sealing leaking pipes and fittings as an emergency repair, repairing pitted or corroded shaft surfaces, and rebuilding bearing housing bores worn oversize. The metal filler (steel or aluminium powder) allows the cured repair to be machined, drilled, and tapped — making it a structural fix rather than a cosmetic patch.
When should I use epoxy putty instead of liquid epoxy adhesive?
Use putty when there is a gap, void, or missing section to fill — not just two surfaces to join. If the gap exceeds approximately 1mm, liquid epoxy will sag on vertical surfaces, crack during cure shrinkage, or produce an under-strength result. Putty handles large gaps, overhead and vertical surfaces, and irregular voids that liquid epoxy can't fill reliably. Use liquid epoxy for close-fitting joints between well-matched surfaces where bond line thickness is minimal.
What PPE do I need when working with epoxy?
Minimum PPE: nitrile gloves (mandatory — the hardener is a skin sensitiser; see Safety section above), safety glasses or goggles (particularly important when mixing liquid epoxy or using syringe packs where splash is possible). For large volumes or confined spaces: chemical-resistant gloves, face shield, and respiratory protection for amine vapours. Wash hands thoroughly with soap and water after use even when wearing gloves. Do not use solvent to remove uncured epoxy from skin — it drives the material into the skin. Use a proprietary skin cleanser or barrier cream and mechanical cleaning.