How to use epoxy putty (cold weld): preparation, mixing, application, storage

To use epoxy putty, clean dirt and rust off the repair area, rough it up with coarse sandpaper, degrease and dry it, then cut off at least 1/3 of the stick and knead the piece with your fingers until the colour is uniform. Apply the putty to the surface — when bonding, to both parts — press them together and hold for 15 minutes. The metal and multipurpose putties set in 45 minutes; after 2.5 hours the repair can be sanded, drilled, loaded and painted.

What you need

Metal epoxy putty, 55 g

Two-component cold weld, 55 g

Multipurpose epoxy putty, 55 g

Two-component cold weld, 55 g

Epoxy putty for ceramics and faience, 55 g

Cold weld for ceramics and faience, 55 g

How epoxy putty works

NANOPROTECH cold weld is a two-component, plasticine-like adhesive based on epoxy resin and an amine hardener. Both components are in the stick: you mix them by hand and the putty hardens. Bond strength depends above all on surface preparation and complete mixing to a uniform colour. Once cured, the putty withstands −60 °C to +150 °C, resists temperature changes and chemical reagents, and can be drilled and sanded.

How to use epoxy putty: step by step

1. Choose the putty for the material. For steel, including stainless steel, aluminium and brass — Metal epoxy putty. For ceramics, faience, porcelain, porcelain stoneware and tiles — Epoxy putty for ceramics and faience. For concrete, wood, marble, stone, plastic and glass — Multipurpose epoxy putty. Cold weld holds poorly on polyethylene and polypropylene (marked PE and PP).
2. Prepare the surface. Clean dirt and rust off the repair area, rough it up with coarse sandpaper, degrease and dry it.
3. Cut off part of the stick. For one repair, cut off at least 1/3 of the stick across its whole cross-section, so the piece has the right ratio of components. Store the rest in a dry, dark place.
4. Knead the putty. Knead both components thoroughly with your fingers — you can wet them with water — until the colour is uniform.
5. Apply and press. Apply the putty to the repair area. When bonding parts, apply it to both surfaces, press them together and hold them for 15 minutes.
6. Smooth and shape. Smooth and shape the putty with flat objects moistened with water. On a wet or oily surface, keep smoothing the putty until it sticks.
7. Wait for it to cure. The metal and multipurpose putties set in 45 minutes, while the seam of the ceramic putty is shaped straight after kneading. After 2.5 hours the joint can be loaded, sanded, drilled and painted if needed.

To seal a leak in a pipe, tap or radiator, see how to fix a leaking pipe; to repair a car's tank or radiator, see how to fix a fuel tank or radiator leak.

Why it may not work

• The surface was not prepared. Sand, degrease and dry the repair area: on an oily surface the bond strength is 20% lower.
• The piece was too small. In a portion smaller than 1/3 of the stick the ratio of components may be off, and the putty will not reach full strength.
• Incomplete mixing or cold. Knead the putty until the colour is uniform. Cold slows curing considerably, so work somewhere warm. Load the joint only after 2.5 hours.
• The stick hardened on the outside in storage. Warm it to +60 °C for about 10 minutes — in hot water, on a radiator or on top of the car engine — and the putty becomes pliable again.

Safety precautions

• Wear protective gloves and keep the components of the stick out of your eyes. If they get into the eyes, rinse with water and see a doctor.
• Do not apply cold weld to surfaces that come into contact with food or to drinking water pipes.
• Keep the sticks out of the reach of children.

Frequently asked questions