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AIRLESS SPRAY GUN TROUBLESHOOTING
DEFECTS
Coarse spray
Excessive fogging
(overspray)
Pattern too wide
Pattern too narrow
Too much material
Too little material
Thin distribution in
center of pattern
"horns"
Thick skin on work
Coating fails to
close & smooth over
Spray pattern irregular,
deflected
Craters or pock
marks, bubbles
on work
Clogged screens
TEST THE PATTERN
5
CAUSE
Low pressure
High pressure
Material too thin
Spray angle too large
Spray angle too small
Nozzle too large
Material too thin
Pressure too high
Nozzle too small
Material too thick
Worn tip
Wrong tip
Material too viscous
Application too heavy
Material too viscous
Orifice clogged
Tip damaged
Solvent balance
Debris in paint
Coarse paint pigments
Incompatible paint
mixture & thinners.
CORRECTION
Increase the pressure.
Reduce pressure for satisfactory pattern.
Use less thinner.
Use smaller spray angle tip.
Use larger spray angle tip. (If coverage is OK,
try tip in same nozzle group)
Use next smaller nozzle.
Reduce pressure.
Use next larger nozzle.
Change for new tip.
Use nozzle with a narrow spray angle.
Thin cautiously.
Reduce pressure and/or use tip in next
larger nozzle group.
Thin cautiously.
Clean carefully.
Replace with new tip.
Use 1 to 3% "short" solvents remainder "long"
solvents. (Most likely to happen with material of
low viscosity, lacquers etc.).
Clean screen.
Use coarse gun filter screen.
Use coarser screen for larger orifice tips.
If thinner was added, test to see if a drop
on top of paint mixes or flattens out on
the surface. If not, try different thinner in
fresh batch of paint.
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