A non-rusting, steel reinforced epoxy putty, providing fast, permanent repairs to items made of ferrous metal or aluminium. It will repair holes, cracks and threads in castings, pipes and tools, and can be used to hold fixtures and signs, to make models and prototypes, to form nuts in situ and to lock threads. When cured, it sets to a hard, dark grey material that can be drilled, sanded, tapped, machined and filed, as required.