How to polish machined raw aluminum?
 

So I've sanded w/ 200, 400, 600, 800, 1000 and 1500 grit paper then polished with white stick and cordless drill/cotton wheel. Not getting scratches completely out nor the luster I'm looking for. Any helpful hints out there? Maybe something w/more speed then cordless drill? What are the best color compound sticks to use? Do I need to go even further w/finer grit sandpaper? What do they use to accomplish this on the billet wheels after machining?
Thanks

What exactly are you working on? The first thing I noticed you are doing wrong is you used paper below 400 grit. Aluminum is soft and doesn't need anything softer than that. Are you wet sanding or dry sanding? If your dry sanding, then stop doing that and start wet sanding it. Also, your not going to be able achieve a good shine with just a drill. You need a dedicated buffer or converted bench grinder using Tripoli compound and a spiral buffing wheel. I would start back over and wet sand it with 400 till I saw nothing but the 400 grit scratches and then work my way up to either 800 or 1000. You could actually stop around 600 if you have a good buffing machine. The Tripoli compound will remove a lot of scratches. You can follow that up, for color, with some white rouge and a soft buffing wheel or Mother's Billet polish

There are a lot of home recipes for different rouges, but what Mako said will work fine. Especially the part about not using courser than 400 Grit and get a higher Speed/Hp buffer. :thumbsup:

I don't use anything finer past 320 or 400 grit or wetsand. Brown tripoly and a powerful enough buffer. You will not get high luster from a drill,you need something much higher RPM's,stiffer wheel and right tripoly stick.Here are some pics of polish work I did on my daily driver couple years ago

http://i274.photobucket.com/albums/j...ombody/015.jpg
http://i274.photobucket.com/albums/j...body/024-1.jpg
http://i274.photobucket.com/albums/j...body/027-1.jpg
http://i274.photobucket.com/albums/j...body/028-1.jpg
http://i274.photobucket.com/albums/j...body/032-1.jpg
http://i274.photobucket.com/albums/j...body/034-1.jpg
http://i274.photobucket.com/albums/j...body/044-1.jpg

Thanks guys, I have been wet sanding up to 1500 removing all heavier scratches w/tripoli. From what I'm reading, I need to invest in a true high speed buffer. Thanks again, I was starting to get a little frustrated w/lack of mirror shine.

Lenie, if you're trying to do this by hand tools, look into Adam's Polish. I've seen very impressive results,but it just takes forever. Spend couple of bucks on a good freestanding buffer,pads and some sticks and you'll be in business.

Thanks Stefan, think I'm going to step up and buy a pedestal polisher. It'll always come in handy.

Lenie, I forgot to ask, what parts are you trying to prep for polishing? How complex are they? Do you have a decent air compressor and D/A sander?

I'm just polishing a set of raw machined billet valve covers. I do have compressor and da's. Went and got a pedestal polisher and it working out pretty well. Thanks for the help.

I was going to say if some parts have cast texture or just rough, you can use a cheap old school D/A, lock it in grind mode ,throw 80/120/180 depending on how heavy the texture is and you can have very smooth surface in no time,clean up with 320 or 400 and it's ready to buff.