Heard they were decent so I bought one. Bought dried sand, medium grit, and a particulate mask to use for this & painting later. So here's the problem. Hooked everything up and the sand doesn't come out the nozzle. Air comes out great! Had the pressure set to 80lbs so I upped it to 100 (max is 125). Still no sand I put the sand in several weeks ago so I thought maybe that was it. stuck a piece of flat stock in there twisted and stirred best I could. Fairly sure I got the center stirred all the way to the bottom at least. Still no sand Suggestions?