MIL-HDBK-1110
in Table 13. Additional problems that may occur with airless
spraying may be associated with excessive pressure, undersized
equipment, and too long or too small paint hoses. Undersized
spray equipment, including hoses, may result in lower production
rates, a pebbly-appearing film caused by poor atomization (nozzle
tip too large), and thin films. Air supply hoses that are too
long or too small may cause instability of the pump, poor
atomization of the paint, or a pulsating spray pattern.
Table 13
Common Airless-Spray Problems and Their Causes and Remedies
Remedy
Description
Cause
Thick center,
Inadequate fluid
Increase fluid
pressure,
thin ends,
delivery or
decrease paint
pinholes
improper
viscosity, choose larger
atomization
tip orifice, or reduce
and
number of guns using one
pump
hour-glass
shape
Teardrop
Clogged or worn
Clean nozzle tip,
replace
shape coating
nozzle tip if necessary
thicker
Rippling,
Pulsating fluid
Increase supply to air
uneven pattern
delivery or
motor, reduc number of
e
suction leak
guns using one pump,
choose smaller tip
orifice, clean tip
screen and filter, or
look for hose leak
Round pattern
Worn nozzle tip
Replace worn tip,
or fluid too
decrease fluid viscosity
viscous for tip
increase pressure, or
size
choose correct tip
orifice
Fluid spitting
Air entering
Check for hose leak,
system, dirty
clean gun, or adjust
gun, or wrong
cartridge and replace
cartridge
if necessary
adjustment
116
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