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Help diagnose spray gun problem

Posted: Thursday, November 10, 2016 8:06 AM Quote
I'm looking for help diagnosing a problem with my spray gun.  It is a Tena Prolite, set up according to the instructions from Devillbis and Stewarts (air supply, filters etc.)  The problem is that I get an uneven spray pattern- it is heavy on the bottom in a vertical spray pattern, or on the left for a horizontal spray pattern.  I've tried different fluid tips and air caps, varied the pressure at the gun from 25-35, even replaced the fluid needle thinking it might be defective.  I took the gun completely apart and cleaned out all the passages, but that did not improve things.

The photo below gives some clues about the problem- you can see the spray accumulating in a defined pattern.  Rotating the air cap 180 deg does not change the pattern and just results in a similar accumulation on the air cap 180 deg from the first.  The photo was after spraying Ecofill, but the effects are similar spraying Ecoprime and Ecopoly thinned to 20 seconds.

Any help diagnosing this would be greatly appreciated.

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Posted: Friday, November 11, 2016 9:50 AM Quote
Jeff,

That is an odd problem.  Air is what makes the spray pattern.  There must be an obstruction in an air passage in the gun, or an air leak of some sort.  If you have replaced the air cap and rotated it 180 with no effect, the air cap would not be the issue.  I would check and make sure the gasket is intact, and that everything is seated correctly.  Make sure you get good air from all the ports inside.  If you don't figure it out, feel free to send the gun in I will see if I can figure it out.

Andy
Andy Humphrey A&P
Stewart Systems Tech Support