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DeVilbiss JGA-504 Service Bulletin

Conventional spray gun
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IMPORTANT: Before using this equip-
ment, read all safety precautions and
instructions. Keep for future use.
The standard JGA-504 spray gun is a general
purpose, heavy duty, high production
spray gun suitable for use with most types
of materials. The fluid passageway is
plated brass and aluminum. The fluid tip
and needle are 300 series stainless steel.
Halogenated hydrocarbon solvents
- for example; 1, 1, 1 - trichloroethane
and methylene chloride - can chemi-
cally react with the aluminum in
this gun and cause an explosion
hazard. Read the label or data sheet
for the material you intend to
spray. Do not use spray materials
containing these solvents with this
spray gun.
Important: This gun may be used with
most common coating and finishing
materials. It is designed for use with mildly
corrosive and nonabrasive materials.
If used with other high corrosive or
abrasive materials, it must be expected
that frequent and thorough cleaning will
be required and the necessity for replace-
ment of parts will be increased.
1 .
Attach the air supply line to the air
inlet (26). An air transformer installed
as close as possible to the gun will
provide filtered and regulated air.
When larger diameter air hoses
are used, it is advisable to use an
8' or 10' "whip end" or a smaller
diameter hose at the gun for
greater flexibility or movement.
2 .
Attach the suction feed cup or fluid
hose to the material inlet.
Protective coating and rust inhibitors
have been used to keep the gun
in good condition prior to shipment.
Before using the gun, flush it with
solvents so that these materials will
be removed from fluid passages.
Mix, prepare and strain the material to be
manufacturer's instructions.
Strain material through a 60 or 90 mesh
1 .
Fill the suction or pressure feed cup
with the material. Do not overfill. Make
sure that the cup lid vent hole is clear,
if using a suction cup.
2 .
Turn on the gun air at the source of
supply. Adjust the atomization air pres-
sure to 35 psi.
3 .
Turn on the supply air to the pressure
cup if used.
Open the spreader adjustment valve
(10) (Fan) by turning the valve stem
Open the fluid needle adjusting screw
(17) by turning counter-clockwise.
6 .
Spray a test area.
If the finish is too sandy and dry, the
material flow may be too low for the atomi-
zation air pressure being used.
If the finish sags, there is too much material
flowing for the atomization air pressure
being used.
Both of the above can be corrected by
increasing or decreasing the atomization
air pressure or the material flow. Pattern
width can be altered by turning the spreader
adjustment valve (10), either clockwise to
decrease the width or counter-clockwise
to increase the width.
See Spray Gun Guide SB-2-001 (latest
revision) for details concerning set up of
spray guns.
To clean air cap and fluid tip, brush exterior
with a stiff bristle brush. If necessary
to clean cap holes, use a broom straw
or toothpick. Never use a wire or hard
instrument. This may scratch or burr
holes causing a distorted spray pattern.
To clean fluid passages, remove excess
material at source, then flush with a suit-
able solvent using a device such as the
SolventSaver™ (see Accessories). Wipe
gun exterior with a solvent dampened
Never completely immerse in
solvent as this is detrimental to the
lubricants and packings.
When replacing the fluid tip or fluid
needle, replace both at the same
time. Using worn parts can cause
fluid leakage. See Charts 1 and 2.
Also, replace the needle packing
at this time. Lightly lubricate the
threads of the fluid tip before
reassembling. Torque to 15-20 ft. lbs.
Do not overtighten the fluid tip.
To prevent damage to the fluid tip
(5) or fluid needle (11), be sure to
either 1) pull the trigger and hold
while tightening or loosening the
fluid tip or 2) remove fluid needle
adjusting screw (17) to relieve
spring pressure against needle
Replaces SB-2-259-A
Repair Kit KK-5058-2



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  Summary of Contents for DeVilbiss JGA-504

  • Page 1 Before using the gun, flush it with or toothpick. Never use a wire or hard The standard JGA-504 spray gun is a general solvents so that these materials will instrument. This may scratch or burr purpose, heavy duty, high production be removed from fluid passages.
  • Page 2: Safety Precautions

    Page 2 SB-2-259-B SAFETY PRECAUTIONS This manual contains information that is improtant for you to know and understand. This information relates to USER SAFETY and PREVENTING EQUIPMENT PROBLEMS. To help you recognize this information, we use the following symbols. Please pay particular attention to these sections. Note Information that you should pay special Important information that tells how...
  • Page 3 Instructions Air Cap No. Needle Packing Gun Body Packing (3 pieces) DeVilbiss 1. Remove adjusting knob and needle GTI-33 Baffle Seal Replacement spring from gun. 2. Partially withdraw needle from gun 1. Remove Fluid Tip (5). body. 2. Remove Baffle (6).
  • Page 4: Parts List

    Page 4 SB-2-259-B 36 37 38 Air Inlet Nipple Fluid Tip 1/4" NPS(M) (Torque to (torque to 15 ft. lbs.) 15-20 ft. lbs.) *Use medium strength thread sealant (i.e. Fluid Inlet Nipple Devcon #2242 Blue, 3/8" NPS(M) or equal) on threads. (torque to 20-25 ft.
  • Page 5: Troubleshooting

    SB-2-259-B Page 5 TROUBLESHOOTING CONDITION CAUSE CORRECTION Heavy top or Horn holes plugged. Clean. Ream with nonmetallic point. bottom pattern Obstruction on top or bottom of fluid tip. Clean. Cap and/or tip seat dirty. Clean. Heavy right or Left or right side horn holes plugged. Clean.
  • Page 6 Page 6 SB-2-259-B Troubleshooting (continued) CONDITION CAUSE CORRECTION Fluid leaking or dripping Packing nut too tight. Adjust. from front of gun Dry packing. Lubricate. Fluid tip or needle worn or damaged. Replace tip and needle. Foreign matter in tip. Clean. Fluid needle spring broken.
  • Page 7 DeVilbiss, Binks, Finishline and other brand pressure and down- gauge. Use to con- not immediately paint. MSDS avail- with gun. spray guns.
  • Page 8: Warranty

    Page 8 SB-2-259-B WARRANTY This product is covered by DeVilbiss' 1 Year Limited Warranty. DeVilbiss Worldwide Sales and Service Listing: DeVilbiss Automotive Refinishing DeVilbiss has authorized distributors throughout the world. For equipment, parts and service, check the Yellow Pages under “Automotive Body Shop Equipment and Supplies.”...