Spray Gun Troubleshooting
DEFECTS
CAUSE
CORRECTION
Coarse spray
Low pressure
Increase the pressure
Excessive fogging
High pressure
Reduce pressure for satisfactory pattern
(overspray)
Material too thin
Use less thinner
Pattern too wide
Spray angle too large
Use smaller spray angle tip
Pattern too narrow
Spray angle too small
Use larger spray angle tip. (If coverage is OK,
try tip in same nozzle group)
Too much material
Tip size too large
Use next smaller tip
Material too thin
Pressure too high
Reduce pressure
Too little material
Tip size too small
Use next larger tip
Material too thick
Thin distribution in
Worn tip
Change for new tip
center of pattern
Wrong tip
Use tip with a smaller spray angle
"horns"
Thick skin on work
Material too viscous
Thin material
Application too heavy
Reduce pressure and/or use smaller tip
Coating fails to
Material too viscous
Thin material
close & smooth over
Spray pattern irregular,
Orifice clogged
Clean carefully
deflected
Tip damaged
Replace with new tip
Craters or pock marks
Solvent balance
Use 1-3% "short" solvents remainder "long"
solvents. (This is most likely to happen with
material of low viscosity, lacquers etc.)
Bubbles on work
Contamination or dust
Clean surface to be sprayed
Clogged screens
Extraneous material
Clean screen
in paint.
Coarse pigments
Use coarse screen if orifice size allows
Poorly milled pigments
Use coarser screen, larger orifice tips. Obain ball
(paint pigments glocculate
milled paint. If thinner was added, test to see if a
cover screen. Incompatible
drop on top of
paint mixes or flattens out on
paint mixture & thinners.
on the surface. If not, try different thinner
in fresh batch of paint.
TEST THE PATTERN
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