How to repair cracked cast iron with epoxy

Bench image by Yuriy Rozanov from

Cast iron parts that are not subject to high heat or excessive pressure are readily repaired with metal-based epoxies. Metal-based epoxies are available in either one or two parts. A one-part epoxy cures when exposed to air, and a two-part epoxy needs to be mixed to cure. Both types of metal-based epoxy harden to a steel-like strength that will provide a semi-permanent to permanent repair on cast iron. The permanence of the repair will depend on the cleanliness of the cast iron crack and the proper application of the metal-based epoxy.

Put on your safety glasses and leather work gloves.

Attach the 4.5-inch wire wheel to the 4.5-inch angle grinder and clean the cracked area of the cast iron with the 4.5-inch wire wheel. You need to remove all contaminants, including paint, from the surface of the cast iron.

Wipe the cleaned area of the cast iron with a clean rag to remove the dust created by the 4.5-inch wire wheel. If you are using a one-part metal-based epoxy, apply solvent to the rag and then wipe down the crack in the cast iron.

Mix equal parts of the two-part epoxy until the mixed epoxy forms one solid colour throughout. Skip this step if you are using a one-part metal-based epoxy.

Press the mixed two-part epoxy into the crack or apply the one-part epoxy into the cast iron crack with the putty knife.

Allow the metal-based epoxy to cure for the time specified by the epoxy usage instructions before using the repaired cast iron part.

Most recent