Question
I've got two Kremlin sprayers. One of them is older than the other. The older one has a much heavier gun than the other. The older gun is leaving a strange pattern. When the pump cycles, the gun stops spraying for a split second, leaving a space with no lacquer. It also sprays a much finer mist just before this happens. I have taken the pump apart and everything seems normal. Can anyone shed some light on this problem?
Forum Responses
(Finishing Forum)
From contributor J:
We call them hiccups; it usually means I have to add oil to the piston pump.
To test this and see which, if either, ball is failing to seat, you can perform a stall test. Trigger the gun while watching the direction of travel of the piston. Stop triggering the gun with the piston in the up direction of the stroke. Wait 60 seconds or so... The piston should not move or creep in the up direction without the trigger being pulled. If it moves at all, the upper ball is the culprit. Repeat the test, stopping the piston in the down position. If it creeps with the trigger closed, it is the lower ball failing to seat.
The only three other (less likely) reasons I can think to see a wink in the fan pattern is: (1) a clogged filter between the pump and the gun. Obviously check all filters for obstruction. (2) Using non-stainless steel hoses with water based or acid catalyzed materials. This would cause an obstruction (water or acid can cause the copper ions to leave the brass fittings used on non-stainless hoses and form a hard mass in the fitting) to develop in the fitting of the hose, eventually cutting off flow though the hose. This would resemble the effect of a clogged filter as well. (3) Putting the Teflon packing in the pump section in upside down, not allowing for the seal to engage in the upward stroke. Make sure the seal is facing with the wide part in the upward direction.
