So during the process of chroming trim, bumpers etc, did companies apply a brass coating first? I was scuffing up my ‘50 Chevy to apply a matte clear and my scotchbrite burned through my hood ornament, revealing a brassy color. I’d like to scuff all the trim and moldings to show this through. Sent from my iPhone using H.A.M.B.
A good plating job consists of a copper base, then nickel, then chrome. The copper is applied thick enough to buff out any small imperfections and helps resist rust..
It's copper as Steve suggested. Triple chrome is copper first, then nickel, then chrome. The copper is put on and sometimes buffed smooth for filling fine scratches or pits. May need a second copper plating depending on desired final results. Then the nickel plating layer is put on, this is the primary corrosion resistance layer. Final chrome is very thin and is mainly for the appearance.
Ok thanks. Since only a small spot came through, I wasn’t sure if it was brass or copper. So I could, with some work, sand the chrome and nickel off the emblems and trim to reveal the copper. Then I could seal it to avoid corrosion? Sent from my iPhone using H.A.M.B.
So remove the corrosion protection of the plating so it can be painted with a clear to keep it from corroding? Clear coats are not designed to prevent any corrosion.
First, you probably can't carefully remove the nickel/chrome, and leave an even layer of copper behind. Most likely, you'll also remove it in places. Next, you'd have to polish the copper to have it look good, it oxidizes so fast. This might remove more, leaving the pot metal surface. Protecting the copper, yes, you can do it. I coated most of the copper on the Kopper Kart, with clear Imron. It's held up well over the years, but it's a show car, stored inside at all times. OTOH, some of the copper pieces we had done later in the build were clear coated by the owner. Not sure what he used, but it didn't hold up well at all.
I worked at a plating shop for many years, so I've got a bit of experience. It's not uncommon for early 50's Chevys to have really thin nickel and chrome plating on certain pieces, as it was claimed to be getting saved for Korean War efforts, although I think GM was just happy to have an excuse to make stuff cheap, as Cadillacs of the same era didn't seem to have this problem. The issue you're going to have is that the copper on an original piece is just "flash copper" plating, which is very thin. If it had been rechromed at some point in the part's life, the copper can be quite thick, as it's used to fill in imperfections, but on a new factory casting, it's generally not much thicker than the chrome and nickel layers, so trying to carefully polish off the chrome and nickel but leave the copper will be tough. That said, a friend of mine with a '52 Chevy buffed the chrome plating off of his grille teeth to show the copper and left it exposed like that. I think it was unintentional at first, just trying to polish up the original chrome, but the chrome was coming off so he made them all uniform, and it looked decent. Clearcoat is likely a bad idea, but there are metal polishes and wax-style coatings you can put on it to try to keep it from getting tarnished. Sanding it off will destroy it, but very careful polishing/buffing might work. If your chrome is already that thin/poor, it might not hurt to try. I think it looks odd, but that's a personal choice.
Thanks man! Any pics of your buddies car? I’d like to see how it all turned out. Sent from my iPhone using H.A.M.B.
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