Problem with abrasive blasting - Aluminum Oxide
#1
Member
Thread Starter
Join Date: Jan 2009
Posts: 30
Upvotes: 0
Received 0 Upvotes
on
0 Posts
Problem with abrasive blasting - Aluminum Oxide
I have a 48 year old classic car that I decided to give its second major restoration to myself.
So I set about getting tooled up to shot blast, starting with a replacement hood as my test piece. After a trial with glass media which seemed slow with a hand held gun/canister I settled on Aluminum oxide media, and upgraded to a 20 lb. Pressurized Abrasive Blaster (Harbor Frt) fed from my 21 gal/125 PSI Compressor running at 90psi with oil/water filters inline.
Some initial tests with small amounts of shot looked good, with the old paint and rust coming off well from the steel hood with a fine mist of shot and air pressure.
The problem - with everything set up per the manual, is that when I open up the trigger, fully, with the tank fully charged now, the abrasive dumps out in one rather slow steady stream that looks like it is 50% shot, 50% air, and 40 seconds later the tank is almost empty. Using the throttle valve doesn't seem to help.
Am I missing something ?
So I set about getting tooled up to shot blast, starting with a replacement hood as my test piece. After a trial with glass media which seemed slow with a hand held gun/canister I settled on Aluminum oxide media, and upgraded to a 20 lb. Pressurized Abrasive Blaster (Harbor Frt) fed from my 21 gal/125 PSI Compressor running at 90psi with oil/water filters inline.
Some initial tests with small amounts of shot looked good, with the old paint and rust coming off well from the steel hood with a fine mist of shot and air pressure.
The problem - with everything set up per the manual, is that when I open up the trigger, fully, with the tank fully charged now, the abrasive dumps out in one rather slow steady stream that looks like it is 50% shot, 50% air, and 40 seconds later the tank is almost empty. Using the throttle valve doesn't seem to help.
Am I missing something ?
#2
It's just my opinion, but I would not media blast sheet metal to remove paint. Maybe in crevices or folds, but on flat metal, a rotating media such as a lap sander would work better. Yes, you will use up a good bit of media with all the valves open fully, as described in the instructions.
#3
Forum Topic Moderator
I agree, flat metal is better sanded or even chemically stripped. If you aren't careful you can warp large flat pieces of metal sandblasting although I doubt your blaster has that much power. Sandblasters probably require more cfm than any other tool so that might also be part of your problem.
#4
fed from my 21 gal/125 PSI Compressor running at 90psi
Your blaster needs 6-25CFM of air.
#6
Member
Thread Starter
Join Date: Jan 2009
Posts: 30
Upvotes: 0
Received 0 Upvotes
on
0 Posts
Excellent, thanks. Obviously I missed the cf of the output and cf for the blaster. I do have a glimmer of hope in that the 40psi rating of the compressor is around the bottom end of the blaster's range but I know that 90psi is a non-starter.