This specification covers a copper brazing filler metal in the form of a paste comprising a viscous mixture of powder in a suitable binder.This produce has been used typically for joining carbon and low-alloy steels and corrosion and heat resistant steels and alloys where high strength, good ductility, and only short-time oxidation resistance above 1000 mDF (538 mDC) are required, but usage is not limited to such applications. Used where inserts of copper wire or sheet are impractical and where carburization of the metals being joined is undesirable.