Quote:

When a car sits in the sun, it all gets hot more or less evenly and slowly. When you balst, I can easily believe the abrupt rate of heating and the fact that it is localized plays a role - if not all of the cause. Of course, the pressure can't help either.



Trust me, it ain't the heat. If I take a flat piece of sheet metal with out any bends in it and lay it on the floor and stand back 3 feet and blast it with sand or alum ox or black beauty, it will bow up towards me and there will be no heat to the metal. If I turn it over and blast the other side it will lay flat again, but will now be slightly larger than it was originally. It's peening or stretching the surface. Plastic media won't do this because it is softer than the metal and won't change the surface profile. Don't get me wrong. I can create heat and destroy a piece of metal if I try. I would NEVER let anyone use sand on the flat part of sheet metal unless you just don't care about your results. You may not even notice the warpage until you go to block it out. Very hard, if not impossible to correct.

The biggest problem with doing your own blasting is not having enough air. I'm talking about CFMs(cubic feet per minute), not PSI. That is why we use a rotary screw compressor that puts out 200+CFM of continuous air.

A 7/16" nozzle @ 80 PSI requires about 180CFM to run continuously. That's alot of air. Even a really good piston compressor may be able to sustain 30 CFMs, not enough without constantly waiting for it to catch up. I can't tell you how many times people have brought me stuff that they have tried to blast and either given up or burned up their compressors. It takes them so long, it starts flash rusting before they can finish a piece.

I'm all for doing everything I can myself, which is why I started my business, but sometimes it is all about having the right equipment for the job at hand.

People tend to think blasting should be inexpensive and easy until they try it themselves. It is a nasty, miserable, dangerous job without the right equipment. I'm talking about full respirated blast helments, big compressors, proper hoses and nozzles, lighting, expensive media, recovery equipment,etc. Most home sand blast units use 1/8-1/4" nozzles that shoot a pattern of about 1/2" in diameter, which is fine for small parts, but will take forever to do larger areas and will barely break the surface of many coatings. Our units shoot about 2-3" diameter and flow enough media (about 600lbs/hr)to remove almost anything. Plastic media only requires 30-35psi vs. sand which takes 60-100psi to move because it is heavier.

But, if you have the patience and the time, go for it.