The problem is water collects at the bottom of the air hose where the sand is introduced...as soon as you stop blasting for any reason the sand gravity feeds into the hose and forms a wet plug.
I have a water separate right at the sand hopper, as well as at the compressor. My poor man's air dryer is 6 vertical sections of 3/4" copper tubing mounted on the wall making the air go up and down and back up again. I installed a 12" dirt leg on each air up leg with a valve at the bottom of the dirt leg, It's amazing how much water I blow out when I crack the valves open. If I do this set up again I'm going to use copper fin tube pipe (hot water heating pipe) as it has the alum fins and will help condense the water even better that the bare tubing.
If your sand gets wet, spread it out on a sheet of plastic on a hot driveway and mother nature will dry it out for re-use later.
If your sand is pulsating out the tip you need to restrict the sand flow a little bit, as your trying to flow to much sand.
Mike B
