From:chuck maize e-mail:hcmaize-A-gmail.com
Subject:RE: RE: Cleaning engine cases - found info Date:Wed Jul 31 05:02:57 2013
Response to:18680
Found it....Backyard Bob 2007:

Backyard Bob's Tech Tip's on Aluminum

I hate to pay other people for doing stuff. They always charge too much, take too long and never do the job the way I imagine it should have come out. So, I experiment and find cheap ways to get quality results; if I don't like the way it comes out I only got myself to blame….and more experimenting. I didn't like the way my aluminum engine cases came back all polished up one time from the plater. I asked him to make them look new and he made them better than new…not what I wanted. Gave'm to another guy. He glass beaded them…looked better but still not what I wanted…looked too clean, no shine. I wanted 'factory fresh luster' without havin' to find a brandy new perfectly preserved NOS part. Here's what I came up with…….
Take a case and clean it thoroughly with any common degreaser. Then take some Mothers Wheel Mist© (available at any Auto Parts store)…get the one that says "NOT for use on polished aluminum wheels….notice the NOT, very important. This one has a mild acid in it that etches the aluminum and that's what we want. Don't be a dummy, read the handling instructions…wear rubber gloves and don't get it in your eyes. Use common sense. Take your aluminum case somewhere where you aren't gonna get in trouble for makin' a mess or killing plants or poisoning the neighbors dog. Give it a really good spray with Mothers Wheel Mist©. It's gonna start bubbling like it's got Alka Seltzer© on it…this is good. After a few minutes rinse it off with water, dry it and spray it again, only this time use a clean paint brush to smear everything around. More bubbling, still good. Rinse with water. The next step is to take Dupont Polishing Compound No. 7© (NOT rubbing compound) and, using a clean dry cloth, start rubbing the case in any way that floats your boat…circles, straight lines, free lance, it doesn't matter. Notice that the compound is turning black…this, again, is good. After rubbing for a few minutes wipe off the compound and re-apply some more. Repeat the rubbing for a few more minutes then wipe it clean. So far not too hard or expensive huh? Only one more step…..spray your case with WD-40© and wipe it clean with another clean cloth. This takes off the remaining polishing compound. You should now be looking at a case that looks just like it came from the Factory; barring any flaws, nicks or scrapes in the metal.
What you have just done is clean, etch, color and brighten an aluminum casting
…and you've got enough stuff left over to do the rest of the parts too! *Got nicks, scratches and wear marks in your parts? No problem, but a few preliminary steps before you do the above.
1. Lightly file, then 'fine sand' the blemish; or just 'fine sand' if it's minor.
2. Take the part to someone who can "Glass Bead" the part (NOT sandblast). This 'evens' the surface finish out and
'blends in' the repair work.
3. Soak the part in hot water with a little liquid detergent; agitate the water ( this opens the pores in the metal and lets
the glass bead debris fall out. Wouldn't want this in your motor!)
4. Rinse, dry, skip the degreaser part, and start with the Mothers Wheel Mist©.

----- ORIGINAL MESSAGE FOLLOWS -----

Find a place that does SODA BLASTING, the aluminum looks new and it does not remove any metal.
----- ORIGINAL MESSAGE FOLLOWS -----
I know there was an old posting on how to clean up aluminum cases. I should have copied but didn't. Can someone please help. Has anyone found a way to remove the aluminum oxide other than bead blasting? Thanks again. 2007