Copper in Welding Wire causing E Coat problems

[doctj]

During welding of a steel assembly, copper is deposited on the surface of the weld. This area will not E Coat and requires mechanical removal of the deposit. Different ways of chemically removing the copper has failed. Please suggest either a new wire composition that will eliminate the copper deposits or something to add to the chemical pre-treat that will sufficiently remove the copper before E Coat.

 

[TVP]

This is a well-known problem in the automotive industry. Either the weld must be mechanically abraded (media blasted, wire wheel/brush, etc.) or it will have to be acid pickled. Acid cleaning, meaning low concentration of acid, is not sufficient, it must be pickled in concentrated acid in order to remove the surface layer.