Polishing help

I'm trying to polish the back rest on my 1985 Maxim. I have polished aluminum for years and never had this problem. I did the oil cap and it turned out perfect. I’m using an all purpose compound (grey) and I’m getting a build-up of black residue. I tried Tripoll (brown) and it did the same thing. I tried cleaning off the wheel but it still has this thin layer of residue on it. The back rest had a little of clear coat on it, but it was sanded off with fine sandpaper. I can take off the residue with a cloth, but there is a lot.
Any thoughts

 

Too much compound on your buffing wheel or it is clogged up. I clean my wheels with a old hacksaw blade holding the blade against the wheel for a second or two to scrape off buildup.Don't know if that is the proper way but it works for me.
Excessive heat buildup will also cause the black residue. A little less pressure with the wheel helps keep it from forming.

 

Rake the wheel, then buff the piece without compound, lightly.

Then if it still leaves compound build-up, dust the piece with flour and lightly buff, with a cleaned wheel.

When I did the brake backing plate for the rear I had to clean my wheel 4 times, lightly compounding each time after raking, then went over it again with flour and my white wheel.

Curiousity question: Are you using different compounds on the same wheel?

 

This could also be casued from excessive heat build-up in the part. If it gets too hot it can "melt" the compound from the wheel to the part.

 

You're eating clearcoat.

That stuff won't sand off, it's made with Superman's ...uh... nemmind.

Before trying to fine wet-sand and/or polish Yamaha polished aluminum, you have to strip the old clearcoat. Sandpaper generally won't remove it; it just makes it nice and shiny so you think you got it. But it's got you. The only reason you're getting black is because you're melting through it enough here and there enough to pick up some metal. The residue is partly melted and re-hardened clearcoat.

Use Aircraft Paint Remover from the auto parts; that stuff is STUBBORN.

 

Thanks Bigfitz, I though I had got it all off.