About a year ago, one of my wife’s good friends if I’d be interested in storing her Sand Blaster. Without hesitation or asking details I said “Sure!” (wondering in the back of my mind why the heck she had one in the first place… which she later explained was for a wood carved sign business she used to have). A few weeks later some of her friends showed up with a full size truck that had a large blasting cabinet in the bed. (I know, really awesome huh?).
I made a place for it in the yard, and decided I’d need to wait for a different air compressor before I could use it. I mean my compressor couldn’t even keep up with our little puny $10 harbor freight sand blaster.
Then, the other day I needed to sand blast some carbon build up off of the valves from a cylinder head I’m re-building. I started to do it with my little cheapo sand blaster, but it really sucked. Sand was hitting my face, and my arms, and…. blech… I was thinking, “If only I had a piece of glass I could put between me and the blasting. Then I remembered! I have a blasting cabinet! I figured I could just use it for a minute or so, and then give my compressor a few minutes to catch up. Boy was I wrong. Instead, I was able to use it for fifteen minutes straight before I needed to give my compressor a break.
How come this huge monster blaster that works 10x as well uses less air then my el’cheapo teeny tiny blasting gun?? It’s the pressure pot! See: http://www.practicalmachinist.com/vb/general-archive/pressure-blast-vs-siphon-blast-80795/
Unfortunately, pressure pot blasting cabinets are not easy to find anymore, and not cheap.
There are two kinds of blasters (well, a lot more, but in general they all fall into two categories). Pressure Vessel/Pot blasters where the blasting media is put into a pressurized chamber and pressure fed into the air stream and out the nozzle, and siphon where the blasting media is siphoned (using the venturi effect I think) into the air stream. My little gun is a siphon type, and the blast cabinet is a pressure pot type. The difference is astounding! I have some coarse sand in it at the moment, and when it’s on you just hear this rumble of sound with a little air, but with the little guy you hear all this air hissing out and just see a little sand. The blasting cabinet also has an auto feed for the pressure pot. The sand accumulates at the bottom of the cabinet, and when you run out, you turn off the air pressure to the pressure pot and pull this little lever up, the top of the pressure pot opens and the sand in the cabinet fills it up. Then you just release the lever and turn the air back on. Viola!
Other people have similar opinions:
It’s amazing how effective blasting is at cleaning things. I now have one more tool in my arsenal for getting things done.
So, if you are thinking of getting a sand blaster, skip the siphon gun, and go right for a pressure pot. You will save yourself hours of time… Even a cheap pressure pot should provide great results: