Troubleshooting
3A1190H
21
Airless Spray Gun
Problem
Cause
Solution
Coarse spray
Low pressure
Increase the pressure
Excessive fogging (overspray)
High pressure
Reduce the pressure to satisfactory pattern distri
bution.
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 tip group)
Too much material
Tip too large
Use smaller tip
Material too thin
Use smaller tip
Pressure too high
Reduce pressure
Too little material
Tip too small
Use next larger tip
Material too thick
Thin distribution in center of pat
tern “horns”
Worn tip
Change to new tip
Wrong tip
Use tip with narrow spray angle
Thick skin on work
Material too viscous
Thin cautiously
Application too heavy
Reduce pressure and/or use tip in next smaller tip
size
Coating fails to close and smooth
over
Material too viscous
Thin cautiously
Spray pattern irregular, deflected Orifice clogged
Clean carefully
Tip damaged
Replace with new tip
Craters or pock marks, bubbles
on work
Solvent balance
Use 1 to 3% “short solvents remainder “long” sol
vents (this is most likely to happen with material of
low viscosity, lacquers, etc.)
Clogged screens
Extraneous material in paint
Clean screen
Course pigments
Use coarse screen if orifice size allows.
Poorly milled pigments (paint pig
ments glocculate)
Use courser screen, larger orifice tips. Obtain ball
milled paint. If thinner had been added, test to see
if a cover screen. Incompatible drop placed on top
of paint mixes or flattens out on the paint mixture
and thinners on the surface. If not, try different
thinner in fresh batch of paint.
Excess paint builds on tip guard Spray gun too close to surface
Hold gun further from surface sprayed
Pressure setting too high
Reduce pressure setting
Drips, spits from tip
Valve seat and/or ball in gun head
damaged or worn
Service spray gun, replace valve assembly
Tip clogs continually
Debris in paint
Thoroughly strain the paint before use
Gun filter missing
Do not operate without inlet strainer
Coarse filter mesh
Do not operate without inlet strainer
