MSV-531 HIGH VOLUME LOW PRESSURE SPRAY GUN
SERVICE BULLETIN
SB-2-243-F
Replaces SB-2-243-E
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Repair Kit KK-4987-2
IMPORTANT: Before using this equip-
ment, read all Safety Precautions and
Instructions. Retain for future use.
DESCRIPTION
The MSV-531 is a slightly smaller, lighter
HVLP spray gun, capable of high produc-
tion. It can be used with a wide variety of
finishing materials. All models are de-
signed to provide maximum transfer effi-
ciency by
l
imiting air cap pressure to 10 psi
(complies with rules issued by SCAQMD
and other air quality authorities)
.
The gun
is intended for use with pressure feed paint
supply only.
Note
The MSV-531 spray gun is not suit-
able for highly abrasive materials (i.e.
porcelain enamel, certain mica paints,
etc.). Premature fluid tip and needle
wear will occur. We recommend
carboloy fluid tips (AV-617 series) and
needles (JGA-409 series) for use with
these coatings.
Most finishing materials can be atomized
with the 28 or 33A air caps. The 28 or 33A
air caps should be used where possible as
they consume less air volume (CFM) and
have slightly better transfer efficiency than
the 46MP and 83MP air caps. However,
more difficult to atomize materials (i.e. low
VOC's) or high flow applications (over 12
oz./min.), are ideal for the 46MP (maximum
performance) air cap, fluid tip and baffle
combination. Also available is the 83MP
(maximum performer) for even higher flows
(17 oz. /min. and above), and viscosities.
Refer to the air cap chart for more informa-
tion. Spray guns with a 28 or 33A nozzle
combination can be converted to 46MP or
83MP if desired.
AIR CAPS - PATTERNS - APPLICATIONS
Air Cap *Typical Pattern Size Typical
No.
and Shape
Application
28
11" long, straight-
sized, similar to
#704 air cap.
Most
common
finishing
materials
33A
9" long, tapered
up to 12
ends similar to #30
oz./min.
air cap.
46MP
11" long, straight-
Low VOC
sided, similar to
materials, 12
#704 air cap.
to 16 oz./min.
83MP
13" long, straight-
Low VOC
sides, similar to
materials,
#765 air cap.
17 oz./min.
and above.
*Actual pattern length dependent upon
fluid tip ID, fluid flow rate, viscosity, air
pressure, and fan pressure.
Operating Pressures:
Air:
100 PSI Maximum (see following chart)
Fluid: 150 PSI Maximum
Standard Combinations Available:
Order No.
* Gun Inlet Pressure
MSV-531-28FF, FX
50 PSI
MSV-531-33FF, FX
50 PSI
MSV-531-46FF, FX
50 PSI
MSV-531-83D, E
65 PSI
•MSV-531-3-46FF, FX
50 PSI
• Models include 300 grade stainless fluid tip
with UHMW poly. needle seat and 300
stainless needle.
* Approximate pressure required to achieve
10 PSI air cap pressure.
Gun models are available with 400 grade
stainless fluid tips and 300 series stainless
needles, and are suitable for most common
coating materials. Select model combina-
tions (see above) are available with 300 grade
stainless fluid tips and needles, and can be
used with waterborne materials or more
corrosive coatings (6.0 pH or above).
These gun models will produce approximately
10 psi cap pressure at the corresponding gun
inlet pressure, as measured at the gun inlet.
Air cap test kits (see Accessories) should be
used to insure 10 psi air cap pressure is not
exceeded.
Note
This gun may be used with chlori-
nated solvents; but, see additional
warnings on page 2.
INSTALLATION
Do not use more pressure than is necessary
to atomize the material being applied.
To provide optimum performance and as-
sure compliance with all air quality regula-
tions, an air cap test gauge kit is available
to determine actual air cap pressures being
used. See Accessories.
Connect the gun to a clean, moisture and oil
free air supply using a hose size of at least
5/16" I.D. hose. Avoid use of quick detach-
able connectors.
Do not use 1/4" ID hose (25'
x 1/4" hose at 18 CFM has a pressure loss of
25 psi. 25' x 5/16" hose at 18 CFM has a
pressure loss of 8.1 psi).
Note
Depending on hose length, larger
hose I.D. may be required. Install an
HAV-501 air gauge at the gun handle
and air cap test kit over tip. When
gun is triggered on, adjust regulated
pressure to desired setting to provide
a maximum of 10 psi at the air cap.
Do not use more pressure than is
necessary to atomize the material
being applied.
OPERATION
Adjust fluid pressure to deliver the desired
paint volume. Refer to the next paragraph
also on “Back Pressure”. Adjust air pressure
and flow to provide a uniform dispersion of
atomized paint throughout the pattern.
Excessive flow rates will result in heavy
center spray patterns. Inadequate flows may
cause the pattern to split. See Spray Gun
Guide, SB-2-001 latest revision, for details
concerning set up of spray guns.
Back Pressure - 46MP & 83MP “Maximum
Performer”
Due to the unique cone shape of the MP
fluid tips, a slight back pressure is created
against the fluid column. This will reduce
the amount of fluid output. To compensate,
increase the fluid regulator pressure slightly.
With 10 PSI cap pressure, back pressures
are approximately 3.5 PSI with the 46MP
and 2.0 PSI with the 83MP.
HVLP requires gun distances of 6-8" be
used. Excess distance will produce inferior
results. Strain material through 60 or 90
mesh screen.
PREVENTIVE MAINTENANCE
Note
If baffle (6) is removed for any
reason, replace the o-ring (5).
To prevent damage to the
o-ring during installation, apply
SSL-10 gun lube to exterior of
o-ring (5) and ID of baffle.
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 instru-
ment.
This may scratch or burr holes
causing a distorted spray pattern.
To clean fluid passages, remove excess ma-
terial at source, then flush with a suitable
solvent using a device such as the
SolventSaver™ (see Accessories). Wipe
gun exterior with a solvent dampened cloth.
(continued on page 3)
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Government NSN No. 4940-01-046-9919 = KK-4987-2
