How do you polish, buff, finish aluminum?

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Hello,I've finally managed to complete the welding portion of something I've been working on for some time.  Right now it's little more than a box but it's a TIG welded aluminum box done by yours truly.  I am here, once again, to suckle on the sweet wisdom and experience of others.  This time, on the subject of putting a mirror and other kinds of finish on aluminum.What I am working with is 1/8th aluminum sheets.  What I have imagined and almost begun is starting with something like 120 grit 5 inch sanding discs on either an angle grinder or a orbital sander.  I just purchased an orbital sander but I don't really know if there is any benefit of using an orbital sander over an angle grinder.  Many of them seem to spin at the exact same rate but I am likely missing something.  I was thinking of getting an adapter for the angle grinder so I could attach hook and loop sanding discs to it and work on the sanding phase that way.I read somewhere that it might be of benefit to use water and a little bit of soap on the aluminum as you sand it.  I plan to always wear a respirator but I imagine it to make the discs last longer and to produce little to not dust this way.  I've also imagined that orbital sanders that have those suction ports at the bottom might not like having soapy water around and inside of them.So I thought I would go to 120, 220, 320, and 400 grit sand paper on the aluminum and then hit it with a buffing setup.  I've seen denim and cotton buffing setups that use various rouges.  I am pretty much completely lost when it comes to what wheels to use on what tools and which rouges to use when and why.  I've imagined that it would be radically faster to have a wheel that spins flat down instead of on it's side but I don't know how that all works out.  Any guidance would be greatly appreciated.Oh, and how do you clean up the inside of a corner weld?  Do you just use an angle grinder with a normal grinder attachment?http://yfrog.com/5bimg2285jj There is the first tank I made, holding 6 gallons of water.Last edited by pinjas; 09-12-2010 at 03:28 AM.Miller 330 a/bp water cooledI believe in gun control, I hold my gun with two hands.  If you want to know why, click here.Buy American or bye America.
Reply:ive been asked to bring aluminum to this type shine before and i used buffing compound and a buffer..... EVERYTHING will turn black.... sad part... it wont last. the only way to make it last longer than a few days is to coat it with clear, but as the aluminum is very shiny and cant get treated with an etching primer, it wont last either... you tryin to bail a sinking boat with a bucket.... if you work yer fool tail off, you can keep it afloat, but eventually, you gonna get tired....nothing fancy, just a few hot glue guns for metalwww.sicfabrications.com
Reply:Certain alloys of aluminum take a polish real nicely,  some won't regardless of your efforts.  Research the grade you are using, I think they are sorted out as four number codes,  for ex:  5010 which describes the portions of variuous alloy components   You can seal it by anodizing the unit which is not that hard, VERY clean first, then hot water, rinse, and you end up with  an ALoxide coat on the surface which is hard.  or...   Go find a guy who polishes gas tanks and items  for the big rigs, these guys have the "technique" down pat. enjoy,Last edited by PapaLion; 09-12-2010 at 08:18 AM.Lincoln Power MIG 215Lincoln WeldPak 3200HDLincon ProCut 25Lincoln WeldanPower 225 AC/DCIf all else fails... buy more tools
Reply:Thanks for the responses guys.  I've been working with 5052 but I haven't settled on which alloy is best for my application.  I've been considering 3003 and 6061.  I am sure many of you understand that basically all places that supply metals carry those three alloys so it comes naturally to compare the three.The plan is to anodize the surface basically immediately after I put a nice shine on the surface.  I've actually found some very specific guides to anodizing and a technique to anodizing that makes it very economical and safe.  At least, safe enough to do it in an isolated garage or basement.  http://www.caswellplating.com/kits/lcd_ano.pdf  This is the best guide I've found so far for anodizing.Miller 330 a/bp water cooledI believe in gun control, I hold my gun with two hands.  If you want to know why, click here.Buy American or bye America.
Reply:yea, 50 ~51~  is what I should have said.  We once took some 2-3" wide strips of the stuff and polished it, then using a small home cobbed gang press with preset spacing which very slowly turned 9 commercial quality 'erasers" at once we made engine turned strips.  The strips locked into a feeder with a ball bearing and cup setup  to advance it the same amount each time.  I was crazy for 62-4 SS Impalas at the time and the SS side trim and dash trim was hard to find.  The whole kit is stashed way under the bench now gathering dust.  UR right anodizing isn't very hard, and with food coloring you can do it in colors, red, and BLACK! which on the engine turned stuff was very kool.Last edited by PapaLion; 09-12-2010 at 02:48 PM.Lincoln Power MIG 215Lincoln WeldPak 3200HDLincon ProCut 25Lincoln WeldanPower 225 AC/DCIf all else fails... buy more tools
Reply:Originally Posted by PapaLionyea, 50 ~51~  is what I should have said.  We once took some 2-3" wide strips of the stuff and polished it, then using a small home cobbed gang press with preset spacing which very slowly turned 9 commercial quality 'erasers" at once we made engine turned strips.  The strips locked into a feeder with a ball bearing and cup setup  to advance it the same amount each time.  I was crazy for 62-4 SS Impalas at the time and the SS side trim and dash trim was hard to find.  The whole kit is stashed way under the bench now gathering dust.  UR right anodizing isn't very hard, and with food coloring you can do it in colors, red, and BLACK! which on the engine turned stuff was very kool.