Summary for bleed through in powder coat Discussion
Bleed through in white powder coat is the core problem here: Don Cooke asks how to stop mill identification markings on aluminum plates from showing through a white powder finish. He says acetone and MEK do not remove the printed marks, and sanding them off is slow and risks damaging the parts. He also notes the coating is already about 10 mils thick, so adding more topcoat does not seem like a real fix. The thread excerpt provided contains only the question, so no answerer’s recommendation is available in the source. Based on the question alone, the practical issue is that the markings must be removed or isolated before coating, rather than relying on extra powder thickness after the fact. The user specifically asks whether a treatment or a powder primer could help, but no solution is shown in the excerpt.
Q. I’ve sent some aluminum plates out for powder coating white that have bleed through problems with the mill identification markings printed on the plates. We’ve tried various solvents to remove the markings, but things like acetone and MEK don’t even begin to remove them. Our only recourse was to lightly sand them off. That creates two problems for us; it’s labor intensive and risks damage to the plates by overzealous sanding. This would seem to be a fairly common problem, but I have not found through searches online that that is the case. At this point, the powder coat is as thick as I can accept (about 10 mils) and I can’t imagine more coats would solve the problem anyway. So is there a treatment that would help, or maybe a primer coat that could be applied beforehand? Is there a “powder primer”?
Don Cooke
Engineer – Nicholasville, Kentucky
February 15, 2012