Airless Spray Gun Operation - Allpro 400E Operations Manual & Parts List

AIRLESS SPRAY GUN OPERATION

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 irreg-
ular, deflected
Craters or pock
marks, bubbles
on work
Clogged screens
TEST THE PATTERN
Good, full
CAUSE CORRECTION
Low pressure
High pressure
Material too thin
Spray angle too large
Spray angle too small
Nozzle too small
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
Extraneous material
in paint.
Coarse pigments
Poorly milled pigments
(paint pigments glocculate
cover screen. Incompatible
paint mixture & thinners.
Spotty Pattern
Increase Pressure.
Increase the pressure.
Reduce the pressure to satisfactory pattern distribution.
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.
(This is most likely to happen with material of low
viscosity, lacquers etc.)
Clean screen
Use coarse screen if orifice size allows.
Use coarser screen, larger orifice tips. Obain ball
milled paint. If thinner has been added, test to see if a
drop placed on top of paint mixes or flattens out on the
on the surface. If not, try different thinner in fresh
batch of paint.
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