1st and foremost, you MUST have an absolutely dry air supply. If moisture is present in the air line it will clump the media resulting in a bad blast. An inline water filter will cost ya about $15 at Lowes or Home Depot. Keep the sand dry as well; in a garage is a good place.

There are two types of blasters, "syphon" and "pressure". You have a syphon model which produces a vacuum in the supply hose with a venturi effect. The blaster I have is similiar to yours but holds 100lbs of media.

It sounds to me like the supply hose (from the hopper to the gun) on your unit is clogged. This can be caused by wet sand or debris in the sand. Make sure you sift your sand when putting it in. I would disassemble the gun and hopper-to-gun hose to check to see if anything is stuck in it. Some models have a supply regulator on the gun itself to adjust how much media is sucked up. If yours has this, make sure it is adjusted correctly.

CAUTION: Understand that when your using sand, it will break down into a dust when blasting. If you breathe in enough of this dust you can get "silicosis" so be sure to use a good quality resperator with a dust rated filter. Simply using a dust mask is not enough. Also, make darned sure your wearing eye protection. Trust me when I say that blasting sand stings like hell if it gets in your eyes.

I JUST bought a full blasting hood for my head from The Eastwood Company ($29.00, 1-800-345-1178, part # 22029) that covers your head & shoulders. It has a large clear panel in front to see out of as well. This will keep all of the sand/rust/etc out of your hair, ears and eyes.

I'm available this coming Saturday or Sunday to stop by and help you diagnose the problem/talk Maverick stuff if your available!

Hope this helps,
Tracy