C-4 powder coating gun surge

A. It seems reasonable to assume that the surging is related to air supply problems.
It could be anywhere from Compressor, air dryer, air line leak, faulty powder pump, faulty powder pump venturis, faulty air supply line to gun, faulty gun venturis, etc.
It is a process of elimination to solve your problem.
If you have identical Wagner c-4's on either side swap the guns and see if you induce the problem on the opposite side.
Then you have isolated it to a gun problem.
Otherwise trace every component back from the gun end.
It is simply problem solving by elimination of variables.
Some people who were not aware of the need for clean, dry air struggled with this problem for ages in the early days of Powdercoat.
Regards,
Bill
I hope this helps.

i. We traced it down and found that we have a bad regulator in the control box. I tried a different gun and had the same problem. I changed the control box -- and that is when I found the culprit. Thank you for your advice..