Thread: polishing aluminum

I was wondering what methods and products are used by different memebers for polishing the aluminum parts for the bike? From initial sanding to final polish and coatings if any would be helpfull.

The hubs are tough in particular. Is it easier with a dremel or just tough it out by hand? Thanks

Toss the dremel, I went thru the same process. Get a polishing pad for your drill or a buffer wheel and use metal polish.

I used a spray enamel to protect after the buffing. The process takes hours so be patient.

Originally Posted by kcjones33

Toss the dremel, I went thru the same process. Get a polishing pad for your drill or a buffer wheel and use metal polish.

I used a spray enamel to protect after the buffing. The process takes hours so be patient.

KC, thanks for the response. How do you deal with the defects in the casting. I'm sanding my fingers raw trying to clean the hubs up in preparartion for polishing. Thats when I thought a dremel would come in handy?

That is beyond me as far as repairing. I would be careful with the sandpaper if your using it dry, it can make some pretty big scratches that will be very difficult to remove with polishing. I used an 800 grit wet to smooth the surface.

Good Luck

Originally Posted by NHct70

KC, thanks for the response. How do you deal with the defects in the casting. I'm sanding my fingers raw trying to clean the hubs up in preparartion for polishing. Thats when I thought a dremel would come in handy?

It depends on how perfect and how shiny you want your pieces to be but what you could do is get a kit that is used to port/polish aluminum cylinder heads and intakes for cars. Eastwood carries a full line of that kind of things. I ported and polished the intake and heads for my corvette. You can make them as smooth and shiny as you want. My combustion chambers were polished to a mirror finish while the runners are supposed to have a rougher finish. You use a die grinder and different grit sanding/polishing cylinders and cones to work it down as smooth as you need. It's time consuming but if your making a show or high performance part, it can be worth it.

On most of my parts I have used a scotchbrite pad to clean the grit off of the part, followed by steelwool, then Mothers Aluminum polish on the buffer wheel followed by Tripoli.
Like mentioned before this take time and elbow grease to bring about results you can be proud of. But it does bring out the nice details that make the bike look like "brand new"



Brian

use as fine of sand paper as you can. like already stated the sand paper can make scratches that are hard to get out. for repairing the larger dings i use a dremel with a sanding tube very lightly and carefully, then go back over it with the super fine sand paper. then i use the buffer as already stated. it takes lots of time and will kill your fingers. but when your done you'll have a bike that your proud of. good luck

I bought a couple polished items from mm2 and I'll vouch for him - he does a very damn fine job!!!

To achieve a lustrous shine requires at least a three step procedure: I have been polishing aluminum castings for about 26 yrs as my family owns an aluminum die casting corporation. There are three solid (semi soft) wheel compounds that are used throughout the industry available in small do it yourself kits at most home improvement stores.

First let me say sand paper is a big no-no. You will add hours to the job trying to remove the fine scratches it leaves. You can use 400- 800 grit however you will get the job done much quicker using compounds.

Before step one below you may want to get a scrap part for trial as the grey compound with the right wheel is very aggressive.

1) Deep marks and imperfections can be removed with what is typically grey aggressive compound (600-800 grit in comparison to sand paper. This polished on a jean or cotton flap wheel (not cotton pressed wheel) running at 1100 -1725 rpm. After all obvious imperfections are buffed out with grey compound you should have a somewhat shiny piece. Don't be afraid to lay into it as long as you can hold onto it and your motor will handle it. Watch out for thin wall details as the grey compound will move some material quite fast.

2) Next a red or brown compound is used at 1725rpm - RPM using cotton wheel only. Higher rpm is easier to work with and achieves better results. Parts get hot at this point. Not an issue. You will find that the compound will pull out the shine much better as the part heats up a little.

3) Finally to achieve an almost chrome look use white rouge compound preferably at 3500 rpm cotton wheel only. Use a light touch. Again heat developed into the part will help the compound work better.

You will end up with compound streaks and build up in nooks depending on the part shape. Final cleaning using very warm (not hot) water and dish soap with a plastic bristle brush or tooth brush will remove the compound and reveal a mirror finish.

Hope this info helps.

A little hint regarding chrome parts. You can pre-polish (raw steel) using grey compund and hard cotton wheel and nickle chrome will plate to a terific finish.

If you want to try and keep it on the cheap they have a couple of nice little kits at Harbor Freight that can be used with a power drill...one in particular has a variety of cloth wheels and small cloth dies/bits that looks like it would work nice for the nooks and crannies...its 17.00