AIRLESSCO 3A1186A Operation - Repair - Parts page 18

Troubleshooting
Problem
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 and
smooth over
Spray pattern irregular,
deflected
Craters or pock marks, bub-
bles on work
Clogged screens
18
Airless Spray Gun
Cause
Low pressure
High pressure
Material too thin
Spray angle too large
Spray angle too small
Tip too large
Material too thin
Pressure too high
Tip too small
Worn tip
Wrong tip
Material too viscous
Application too heavy
Material too viscous
Orifice clogged
Tip damaged
Solvent balance
Extraneous material in paint
Course pigments
Poorly milled pigments (paint
pigments glocculate)
Test the Pattern
Good, Full
Solution
Increase the pressure
Reduce the pressure to satisfactory pattern dis-
tribution.
Use less thinner
Use smaller spray angle tip
Use larger spray angle tip (if coverage is OK, try
tip in same tip group)
Use smaller tip
Reduce pressure
Use next larger tip
Material too thick
Change to new tip
Use nozzle with narrow spray angle
Thin cautiously
Reduce pressure and/or use tip in next smaller
tip size
Thin cautiously
Clean carefully
Replace with new tip
Use 1 to 3% "short solvents remainder "long"
solvents (this is most likely to happen with mate-
rial of low viscosity, lacquers, etc.)
Clean screen
Use coarse screen if orifice size allows.
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.
Spotty Pattern,
Increase Pressure
ti15991a
3A1186A