Picked up a correct part no./ correct dated alternator for my 78SA. The one presently on it is not a Corvette part no. and is dated early79 so I figure it was a warranty replacement back when the car was new. Gonna take the guts out of the 79 one and put em in the 78 case but I want to brighten it up without making it too bright. Bead blast it? I know sand blasting will ruin the finish but I never had any experience with beads. Is this the way to go? I see rebuilt ones that have the finish I'm looking for. How do they clean up the case?  Mike

Some of the rebuild places are using walnut shells for blasting media. Bead blasting with glass will still "damage" the surface somewhat. Does your case still have the ink stamp on it? Might want to protect that, if it does.
A chemical cleaner might be a good alternative. I've used some aluminuminum wheel cleaner(Eagle One) with really good results in the past.

I don't have it yet, it's on the way. Supposed to be in excellent condition so may not really need a lot of cleaning up. But I really do want it to look "new" without looking wrong. I'll try the aluminuminum cleaner first. Ya think plain aluminum cleaner will work?  Mike

I've also used aluminum cleaner on alternators with good results.

[QUOTE=mkapp7879]I'll try the aluminuminum cleaner first. Ya think plain aluminum cleaner will work? Mike[/QUOTE]

Maybe...might start with the type for koated aluminuminum wheels..it's not as harsh.

After you disassemble the alternator, use some Castrol Super Clean and a plastic bristle brush to get any contaminants out of the pores in the aluminum and rinse it immediately.  If you allow it to dry, the Super Clean will darken the aluminum. (Don't forget to wear rubber or Nytrile gloves.)  After the surface is clean, use a good liquid metal polish and the same bristle brush.  I highly recommend using Heavy Metal Polish.  It is specifically formulated for aluminum and comes in three grades. The blue is for fine polishing, the green is a medium grit and the red is a course grit.  Heavy Metal has a wax in it so when you are done, the pores will be resistant to comtaminants.     1969 L462007-03-26 06:02:58

Would you believe I ended up using Bar Keepers Friend? I finally got the thing Friday and of course I had to go right out to my workbench and take it apart. Pretty good condition, just a little dirty. Decided to use just the case half that has the date on it. Didn't get a chance to buy any alum cleaners so I figured I'd try what I already had handy. Cleaned it with lacquer thinner and then brought it into mama's kitchen and saw what was available. The Bar Keepers and a toothbrush and a plastic scouring pad. About 5 times scrubbing and rinsing. Each time more and more black rinsed off. Looked perfect. With it reassembled to the "old" case half you can't tell the difference between the 2  halves. I got a rebuild kit so now I'll reassemble the other one with new parts and have a spare. Something more for my box-O-parts!  Mike

Great info, Mike!
Did ya tell Mama what you did with her stuff?!

[QUOTE=Adams' Apple]
Did ya tell Mama what you did with her stuff?![/QUOTE] She got home from work and walked in on me doin' it! "NOW what are ya doing?". Had to show her what I got. "What?, these numbers here?". She didn't seem to understand just how important those numbers are!!!!  And ya think after 30+ years she knew me.

Then I noticed her little power toothbrush..."can I use that?...."

mkapp78792007-03-26 21:08:03

[QUOTE=mkapp7879] Then I noticed her little power toothbrush..."can I use that?...."

[/QUOTE]

                           "Why, sure, Honey, go ahead..."