sandblasting

This is the main board for discussing general techniques, tools, and processes for fusing, slumping, and related kiln-forming activities.

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charlie
Posts: 961
Joined: Mon Mar 10, 2003 3:08 pm

Post by charlie »

Lynne Chappell wrote: So of course we went to overkill on the upgrade, but it hardly ever turns on, even though we have a 200 lb pot and an air hood both running from it.
isn't breathing compressor air incredibly dangerous? there's good reasons that scuba tanks aren't filled with normal air compressors.
elin
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Joined: Tue Oct 07, 2003 11:11 pm
Location: portland, or
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Post by elin »

First, I've recycled 120 grit Silica Carbide in a pressure pot before with no problems. I've done the same with 120 Alumina Oxide. No problems at all, as long as you run it through some screens to sift out the junk. The Carbide retains its cutting power even after it's been used better than the Alumina does. When Alumina breaks, the edges get rounded unlike Carbide that breaks sharp-- or at least that's how it was explained to me. Each has some advantages.

Second, I've used both of those media to carve through thick glass, and do light photo-resist detail, and half-tone surface etching. It's just a matter of adjusting the nozzle size, pressure, sand mixture, and distance from the piece. I wouldn't use a coarser grit for the photo-resist, but I have used 100 grit for serious carving. And, I don't reccomend sand, for the health reasons described.

With that said, I confess, I am fortunate to have access to some wonderful, high powered equipment that I do not own-- A huge (don't know how big) compessor, 300 lb pot with reclaiming system, in a blast booth that can fit a 9' x 14' piece to blast, with a bunny suit, and air hood... And the air is supplied from a special (free-air)compressor for clean breathing air. Yes, I am spoiled... I know, but I fully reccommend it! 8) :lol:
-elin
Jackie Beckman
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Post by Jackie Beckman »

Yes, I am spoiled... I know, but I fully reccommend it!
This is my new favorite quote from the board! Ha! Love it.
Darrin Strosnider
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Joined: Tue Mar 11, 2003 10:33 am
Location: Desert Southwest

Post by Darrin Strosnider »

charlie wrote: isn't breathing compressor air incredibly dangerous? there's good reasons that scuba tanks aren't filled with normal air compressors.
Compressed air from a "normal" compressor is compressed air and, depending upon the type of compressor, it might have traces of oil or other lubricants in it (which is why you have a perception it is dangerous, and it probably is, long-term).

Compressors for refilling breathable air supplies have lubricant systems that are isolated from the air that is being compressed, as well as special filtration systems that remove moisture and other things harmful from the air. If moisture is in the air, it can cause the inside of the tank to corrode, which introduces iron or aluminum oxide into the breathing air. Have you ever drained your compressor tank? The orange water coming out has iron oxide from the steel tank corroding due to moisture in the compressor tank. This is why you have to have visual inspections performed on scuba tanks regularly, and why the old steel ones had to occasionaly be tumbled.

If you live in a climate where you have high humidity, you should be diligent about draining your compressor tank after each use, to reduce corrosion forming in the tank.

-stro
Lionel
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Joined: Wed Aug 20, 2003 2:49 am
Location: Honolulu
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Post by Lionel »

Balard has a filter system to remove oil first (Coolesser (sp)) and then a yellow breather filter with a three stage unit inside. Cost $3-400.00.

Don't just hook it up and hope for the best. It needs testing for CO2 and carbon monoxide and ......... Testing cost $65.00 shop visit for air quality.

Moisture is a whole other issue. Here in the tropics I have auto valves before an air dryer and at the tank. Cost $900.00. Dry air is good to breath and good to blast with. Wet air clumps like spit balls.

Life is short enough - safety equipment is cheap.
Lionel Prevost
psg@lava.net
(808)262-7771
elin
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Location: portland, or
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Post by elin »

Moisture is a whole other issue. Here in the tropics I have auto valves before an air dryer and at the tank. Cost $900.00. Dry air is good to breath and good to blast with. Wet air clumps like spit balls.
We have the same issues here in Oregon. I have found that leaving the pot empty between blasting sessions helps keep the medium dry from any moisture that gets through the auto, and manual bleeder valves.
Life is short enough - safety equipment is cheap.
Well put! Play it safe, it's worth it!
-elin
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