I am bead blasting cast aluminum with #10 glass bead. The aluminum is bubbling and then pits form. I’m also getting squiggly lines in the metal. I’m running at 50psi and have dry air. What might be causing this. Anyway to fix it? I’m worried it may have ruined my piece.
Bead Blasting Help
- Thread starter c20Dude
- Start date
finn
Well-known member
There’s a relatively thin smooth skin on die castings, but can be a lot of porosity under that skin.
Proper casting techniques and processes can minimize the porosity, but we ended up specifying a vacuum impregnating process with a sealant to make engine parts like oil cooler headers leakproof.
what you’re seeing isn’t unexpected.
Proper casting techniques and processes can minimize the porosity, but we ended up specifying a vacuum impregnating process with a sealant to make engine parts like oil cooler headers leakproof.
what you’re seeing isn’t unexpected.
Thanks. Any tricks to getting the as cast look again?
Thanks
Firebrick43
Well-known member
Sand to remove the diecast lines and shrink and then reblast or vapor hone to start with.
Small diecast parts you can put in a vibratory polisher with a ceramic media to remove the "frosting" from the glass beads. I know there are massive vibratory polishers used in industry, but not too many of us are going to have them in our garage.
If you go the scotchbrite route, some sort of a lubricant helps. PPG used to make an aluminum prep solution that was a mild acid? that IIRC I used for this purpose. Or maybe I used it after the scotchbrite polishing. Don't go too far or you will end up with too shiny.
The PPG was probably something like this
www.eastwood.com
Here are the PPG listings. Maybe I used both the 533 and/or the 501. I'll look to see if I have any of it left.
Edit- Ok, I checked, and I have both the PPG 533 and the 501. It doesn't look like I used much, if any, of the 533, but have used most of the 501. I put the 501 in a plastic spray bottle and spritz it on and manually polish. And then I guess gave it a final spray down. Both are mild acids, so use outside with the basic safety precautions.
If you go the scotchbrite route, some sort of a lubricant helps. PPG used to make an aluminum prep solution that was a mild acid? that IIRC I used for this purpose. Or maybe I used it after the scotchbrite polishing. Don't go too far or you will end up with too shiny.
The PPG was probably something like this
Eastwood Aluminum Prep and Cleaner Quart Trigger Bottle
Removes stains, corrosion... brightens aluminum surfaces
www.eastwood.com
Here are the PPG listings. Maybe I used both the 533 and/or the 501. I'll look to see if I have any of it left.
Edit- Ok, I checked, and I have both the PPG 533 and the 501. It doesn't look like I used much, if any, of the 533, but have used most of the 501. I put the 501 in a plastic spray bottle and spritz it on and manually polish. And then I guess gave it a final spray down. Both are mild acids, so use outside with the basic safety precautions.
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