View Full Version : Harley Aluminum Polishing

08-07-2012, 09:47 PM
Hi -

A friend at work inherited a Harley when his father passed away. He was asking me how to polish the engine side covers (not sure if that's the right description). I looked at the aluminum and it has a weird pattern on it. Like it might be salt damage? Which isn't out of the question here in MN. But you can't feel the defects. The aluminum feels smooth. I thought maybe a clear coat failure, but he said he tried to polish the aluminum and his rag turned black. So I'm assuming no clear coat.

Any ideas? I have zero experience with motorcycle detailing. I suppose I could take all of my metal polishes and cleaners over there and see what I can do.

Any help or ideas would be appreciated. I can take some pics too.


08-08-2012, 07:57 AM
Try any Billett aluminum cleaner. It has to say billett. I used aluminum cleaner on my catch can from water etching and it was a no go. I brought some Mother's Billett aluminum cleaner and it looks brand new.

tuscarora dave
08-08-2012, 08:28 AM
If there is no clear coat on those cases/covers, to get the best results he should consider removing them and buffing them out on a bench style buffing wheel using emory compound and polish sticks for cutting, polishing and finishing aluminum. As with polishing anything else, he may find that the least aggressive polishing or finishing stick will do the job just fine. On the other hand, if the salt damage is deep enough it may require some sanding first. Grit would depend on the severity of the salt etching of course.

I'd recommend not sanding with anything more coarse than 1000 grit and continue sanding down through 2000 grit then finish with 3000 grit. After sanding the cases, use an "emory compound stick" with the wheel on the bench style buffer as a first step, then follow that with an aluminum polishing stick working slow and overlapping sections against the buffing wheel so that the polish on the wheel breaks down leaving a nicely shined look.

You'll find that using a rotary buffer like what is used for buffing paint will not be fast enough to produce any really nice results. This is really time consuming, tedious and dirty work.

If the cases are coated and the coating is compromised. Aircraft paint stripper will remove the coating with a ton of elbow grease and then go through the sanding and buffing steps as outlined above.

In case you don't know what type of buffer I'm talking about, here's an image of the style of buffer that will yield the best results for motor case/cover polishing.


And the various compounding/polishing sticks.


tuscarora dave
08-08-2012, 08:33 AM
If time is money to your friend, he may want to consider purchasing new covers/motor cases. The time it takes to do all of this stuff can become staggering. For about $500-$1000 he can buy all new covers and chrome accessories.

George Brown
09-03-2012, 11:37 PM
Hello Community,

You have to polish aluminum to a near chrome finish. You simply have to polish the living hell out of it, then after you do, you have to maintain it by periodically polishing the hell out of it some more. That's why chrome is so popular!!!

Best Regards,