I used a pressure pot blaster for the first time recently. It worked for about 4 minutes before it started to blow out nothing but air. The nozzle was not clogged there was in fact no media in the hose.
If I tap the sand valve with a hammer it will work for a few moments. the same will happen if I mess with the valve switch. I even tried to leave the deadman valve open and just crack the sand valve slightly until I got media flow but the darn thing would clog in a minute or two.
A person mentioned reversing the inputs on the 3 way pipe connected to the sand valve. Once again it works for a minute or two and then clogged. While I had it apart I checked the ball balve which seemed to be working fine with no obstructions.
The media is not clumped up and I have two dryers inline as well as 25 ft of hose in a bucket to cool the air. I don’t think that is the problem.
I also get this thing that happens where I will slowly open the sand valve with the deadman held open and nothing will come out until I have the sand valve opened completely and it will work fine like if the valve was only cracked open and then out of nowhere the media will pour out with no pressure (as it should since the valve is wide open)
There does not seem to be any obstructions as I acccidently took the fill cap off the tank while it was pressurized and it blew off. I took all the other pieces apart and they all appear fine.
I am begining to suspect my blast media, I am using 20/40 grit coal slag. Would I be better off using something like 80grit glass beads? Is there some other technique I need?