adjustments set all the way to one extreme or the other. The paint gun
will come with instructions, but there’s trial and error involved in
adjusting the gun as well. Testing and practice are both important when
setting up a gun.
Most paint guns have three common adjustments: air flow, liquid flow
and fan. All of the adjustments are very important. Air flow will vary
depending on what product is being sprayed. Primer will require more
air pressure than color, because it is a heavier material. HVLP guns use
less pressure, but more volume of air than siphon-feed guns. The
instruction manual will have initial guidelines, but these settings are
often low. Many times, these settings are referring to “at the cap” air
pressure, not the air pressure as it comes into the gun from the air line.
Setting the air pressure at the bottom of the gun to “at the cap”
recommendations will leave the air pressure too low. When in doubt, 24-
32 lbs. at the air line is a good starting point; be sure to test it with the
material that’s going on the job.
Liquid flow is controlled by a positive stop needle that restricts the
total travel of the trigger assembly. This is the only adjustment that is
always in the same spot, regardless of the design of the gun. Adjustment
of the liquid flow is best set just off the maximum for primer, because it
needs to go on fairly heavy. The colors are thinner and may require less
fluid flow. This adjustment is also heavily influenced by the technique of
the painter. A fast mover will need more liquid (and air) than a slower
painter. There’s no right or wrong way here. Whatever feels best
probably is best.
The fan setting adjusts the width or narrowness of the paint pattern.
This is the adjustment that is frequently changed, depending on the
shape of the item being painted. Long, narrow pieces require a narrow
fan, while panels get a wide fan pattern. Most of the time, turning the
fan needle inward (tighter) narrows the fan. On guns with a side-mount
adjustment, there’s usually a narrow to wide engraving that makes the
method of adjustment obvious. A really narrow fan pattern can require
an air pressure adjustment. When setting the fan, a painter’s technique is
also an issue; about a 70 percent overlap is required to prevent “stripes”
appearing in the paint due to improper overlap coverage. Fanning too
wide often leads to “dry spray” as the paint starts to dry before making
contact with the surface. Developing technique takes time and practice.
singke
(singke)
#1