Removing Welding Flux

Question:

Currently, one of our welded parts that goes through an electrocoat system comes out with spots that are not covered. This leaves a small, gold-colored dot in the areas where welding has occurred. Is there any economical way to remove the welding flux in order to have a complete coat of paint? G.F.

Answer:

As you have deduced, weld spatter/slag is non-conductive; therefore, it will not paint in an electrocoat system. I believe you have two options. Probably the best is to clean it off. Depending on the accessibility and total surface area, a mechanical means (possibly a grinding or polishing wheel) would be the most effective and quickest at removal. The second option would be to use a touch-up paint as a secondary operation. I would only recommend this if you are already doing so or get approval from your customer. You would have to use a touch-up paint that would match the color and gloss of your electrocoat, but be aware that it will not have the same performance characteristics as your electrocoat. Therefore, if there are stringent requirements and if this area is significant or very noticeable, that may not be a very good option.