Ok, well this is tough since you dont tell us what type of blaster you are using. I am going to assume you are using a blast cabinet. I would first start off by checking the gun . I know on my cabinet, the gun gets clogged every so often, as a matter of fact, I keep a screw driver next to it for quick cleaning. sometimes the clog is a the ceramic tip and it needs to be unscrewed and tapped on the palm of your hand til something falls out. Other times it can be at the inlet hose part that connects to the gun. Undo that and make sure there is not junk in there too. This usually is because something fell into the hopper that was bigger than what should be in there. Remember you need consistant media. If you are using ol playground sand, that is no good. Too inconsistant, plus it usually has moisture in it. Which is also something to avoid. If you need cheap media, go get some kiln dried sand from a brick place. You can get a 100lb bag for like $7. It is very consistant a bit smaller than playground sand but much better. And be warned sand is not the best media as there is health related problems from silicosis (the dust from sand). I used Aluminium oxide in my cabinet and it is pretty agressive. I bought a set of Sebring wheels at the Mopar Nationals a few years ago. The clear coat was really bad on them. I cleaned them and hit them with an aircraft stripper and it literally did little to them. I tossed em in the blast cabinet and the aluminium oxide took of the clearcoat, paint, and even textured the machining grooves out of the wheel. Perfect for paint. Mixed up my own paint from the paint store and they look awesome.
If you are using a pressure tank, I would say dump all the media out, start with a known good media, like aluminium oxide and play with the valve at the bottom til it flows nicely. Don't give up too soon. But if you decide to, let me know. I'll take the chally wheels off your hands...and like my buddy likes to say the swap meets, "and I'll be doing you the favor!" ....lol Good luck.
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