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Stains in Brass

Posted: Fri Oct 18, 2019 1:41 am
by Rob Patterson
Hi Folks,
Next weekend is our car clubs annual "Show-n-Shine" and I'm getting my new-ish Speedster ready for its first Club outing.
I've been polishing brass for the first time (for the car, not me) and its taking an eternity because its new, I suppose. I'm just about finished, but there is a problem that you might be able to advise me on.
Some of the brass, has stains in it, that wont polish out. There is a section of brass channel that skirts around the firewall, that has these deep cherry coloured/black-ish stains. Also a couple of the hubcaps are stained too. Some of it, the small, minor stains, have come out with a lot of elbow grease, but the deeper ones wont budge.
If you know what I'm talking about and have come across this before, can you offer me some advice on how to go about removing it please?
Would a really fine wet-n-dry paper, say 2000, do the job? Then polish it as per normal? Or is this the wrong way to go.
Your advice please.
Cheers,
Rob
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Re: Stains in Brass

Posted: Fri Oct 18, 2019 3:05 am
by Shirkwood
If I'm understanding you correctly, these are copper colored spots on the brass. Officially, I believe it is dezincification. The zinc has left the brass alloy. You might be able to sand through them. I like to leave them. It is proof that your brass is original.

Re: Stains in Brass

Posted: Fri Oct 18, 2019 10:02 am
by Corey Walker
If Spots won’t polish out I sand them as you said with fine sandpaper then use a buffer-polisher.

Re: Stains in Brass

Posted: Fri Oct 18, 2019 10:41 am
by Rich Bingham
"Dezincification". ❤️
Look it up in your Funk & Wagnall's

Re: Stains in Brass

Posted: Fri Oct 18, 2019 11:19 am
by Mark Gregush

Re: Stains in Brass

Posted: Fri Oct 18, 2019 4:05 pm
by Rob Patterson
"Thanks" Gents.
This is new brass, but I suspect some of it came from China.
Cheers,
Rob