Adhesive type
Epoxy putty
Hand-mixable epoxy in stick form for rebuilding missing material, filling large gaps and moulding shapes in place.
Also sold as repair putty, epoxy repair stick, kneadable epoxy.
Epoxy putty is a two-part epoxy resin and hardener supplied as concentric layers or separate sticks with mineral or metal filler. Kneading brings the reactive components together. Once mixed, it cures through the whole mass by chemical reaction, so a thick patch does not need air to dry. The mixing ratio still matters. With a repair stick, cut square across both layers and knead until the colour is completely uniform. Streaks mean unmixed material and leave soft spots. The filler gives the uncured material body, allowing you to rebuild a corner, plug a hole or form a temporary thread boss. After cure, many grades can be drilled, filed and painted. It is usually better as a patching and rebuilding material than as a thin, high-strength structural adhesive. Press it hard into a keyed surface so it wets the substrate before shaping the outside. Epoxy putty is useful on metal, rigid plastic, masonry and ceramic when the specific grade lists them. It is poor on flexible parts, oily surfaces and low-surface-energy plastics. Fast sticks can become firm in a few minutes, leaving little time to mix and place them. Water, fuel, potable-water and high-temperature claims are product-specific. Do not infer them from the word epoxy.
At a glance
- Strength
- High
- Flexibility
- Rigid
- Gap filling
- High
- Water resistance
- Water resistant
- UV resistance
- Moderate
- How it cures
- Chemical reaction
- Typical working time
- 3 to 15 minutes
- Typical full cure
- 1 to 24 hours
- Typical service temperature
- -30C to 120C
- Needs clamping
- No
- Two part
- Yes
These figures describe the family in general. Always use the numbers on the datasheet for the product you actually buy.
What it is for
Rebuilding chipped metal or rigid plastic; plugging holes and cracks; shaping missing corners; small plumbing repairs where the grade is approved; filling damaged threads before redrilling; making rigid fillets around fittings.
Where it falls down
It is rigid and can crack on flexible or vibrating parts. It bonds badly to oil, silicone contamination, polyethylene, polypropylene and PTFE. A smooth patch over paint is only as strong as the paint. Fast grades leave little working time. Thick filler improves shape but does not make every grade suitable for structural loads, fuel, drinking water or continuous immersion.
Getting a good bond
Remove paint, rust, scale and grease. Abrade to sound material and create a mechanical key. Dry the surface unless the product specifically permits wet application. Cut the required amount cleanly and knead until the colour is uniform, including the centre. Press firmly into scratches and undercut edges before shaping with a damp tool if the instructions allow it.
Safety
Uncured epoxy components commonly irritate skin and eyes and can cause allergic skin sensitisation. Once sensitised, a much smaller later exposure can trigger dermatitis. Avoid kneading with bare fingers even when the packet suggests hand mixing. Use disposable nitrile gloves that are compatible with the SDS, change contaminated gloves, and keep resin off tools and door handles. Sanding cured putty makes filler and resin dust, which should not be inhaled.
Materials it suits
| Material | Suitability | Notes |
|---|---|---|
| Cast iron | Excellent | Epoxy putty is rated excellent for this material as an application-level assessment, not as a blanket manufacturer claim. The prepared surface must be sound and consistently keyed where the finish permits. Suitability still depends on the other substrate, joint design and service environment. Abrade first |
Last reviewed 8 October 2026.