Description U-POL WELD THROUGH #2 COPPER RICH PRIMER x 3 High adhesion, super-conductive Copper rich Weld Through Primer specially formulated to offer the best in rust protection for both SPOT, MIG and TIG welding. Contains high purity Cooper giving excellent conductivity as well as high adhesion to metals. gives a durable, semi-flexible metallic finish, which leaves a corrosion resistant surface.