Graco A Series Operation And Parts List page 4

Spraying
Spraying
The spray pattern can be adjusted by changes to:
• Tip size
• Fluid and/or air flow
• Air needle (1a) position
The standard applicator adjustment is to adjust the air
needle (1a) slightly behind the fluid tip. Fully open the air
ball valve (1b) for the minimum air flow necessary for a
good pattern.
NOTE: Installing needle (1a) too far forward can reduce
orifice size, stopping material flow.
Air bleeds from the applicator nozzle whenever the
applicator air ball valve (1b) is open. Close the valve to
stop the air if desired. Otherwise, the air valve can stay
open during priming.
Adjusting the spray pattern requires testing to balance
the fluid flow and the air to the applicator, and requires
the correct tip size.
Spray Techniques
1. Test the spray pattern on cardboard. Hold the appli-
cator 18-30 in. (455-760 mm) from the surface. Use
this spraying distance for most applications.
2. Adjust fluid flow until material flow is adequate.
3. Adjust the applicator air ball valve (1b) to achieve a
uniform round spray pattern.
4. Consider the size of aggregate in the material and
the coarseness of the spray pattern. Larger tips
allow heavier patterns.
5. Overlap each stroke 50%. A circular overlapping
pattern may give the best results.
When spraying small confined areas use the air ball
valve (1b) and air needle (1a) to make fine adjustments
without adjusting the pump.
4
Material Flow Adjustments
For a lighter spray pattern, adjust the air needle (1a)
closer to the fluid nozzle and/or reduce the fluid flow.
For a heavier spray pattern, adjust the air needle (1a)
farther back from the fluid tip and/or increase the fluid
flow.
NOTE: Withdrawing needle (1a) too far can force air
back into fluid hose, stopping material flow.
Air Flow Valve Adjustment
To decrease air flow, turn air ball valve (1b) clockwise.
To increase air flow, turn air ball valve (1b) counterclock-
wise.
Check material and thin as needed to maintain the
proper consistency. The material may thicken as it sits
and could slow down application or affect the spray pat-
tern.
Flush and dry applicator thoroughly at the end of each
use. Blow air through the needle after the applicator is
clean to ensure no material is blocking air flow.
Installing Nozzle Retaining Cap
1. Place nozzle retaining cap (13) over the top lip of
the applicator housing.
2. Turn the rubber retainer back and forth to make sure
it is fully seated.
NOTE: The rubber gasket in the cam and groove
inlet fitting and the rubber nozzle retainer should be
hand-cleaned and dried after each use.
3A3438D