General Safety Information; Spray Gun Set-Up - Husky HDS780 Manual De Instrucciones

Operating Instructions and Parts Manual
General Safety
Information
(Cont.)
away from sharp objects. Bursting air
hoses may cause injury. Examine air
hoses regularly and replace if damaged.
7. Always use a pressure regulator on
the air supply to the spray gun.
appropriate water/oil removal equip-
ment may result in damage to machin-
ery or workpiece.
Introduction
The spray gun is a vital link in any
finishing application. In addition to
operating the spray gun properly, tech-
niques of surface preparation and paint
preparation must be understood. These
instructions will explain the differences
among various spray technologies and
serve as a guide in the proper opera-
tion and techniques of spray painting.
Refer to the Replacement Parts Manual
for model specific information.
SPRAY GUN TERMS
Atomization - Conversion of bulk liq-
uid to spray droplets (mist).
Bleeder – In this mode, air passes con-
tinuously through the gun whether
spraying or not. This mode is generally
used when the air is supplied by a con-
tinuously running compressor that does
not have a tank.
Bleeder/Non-Bleeder – Indicates
whether air flows through the gun con-
tinuously or as the trigger is pulled.
External Mix – Process where the air
and paint are mixed just after leaving
the nozzle. This type of mix should be
used for fast drying paints and when a
high quality finish is needed.
Feed – Method used to bring paint into
the gun for spraying.
Fluid Control Knob – Used to control
the amount of paint being mixed with air.
Gravity Feed – Method of paint feed
similar to the siphon feed method.
However, the cup is inverted to create a
positive fluid pressure at the nozzle.
Internal Mix – Process where the air
and paint are mixed inside the air cap
just before being sprayed. This method
is best for heavy bodied, slow drying
paints and can only be used with the
pressure feed method. Do not use fast
drying paints with internal mix. The
paint will dry inside and quickly clog
the air cap.
Keep
Mix – The mixing of paint and air when
hose
spraying.
Non-Bleeder – In this mode, air flows
only when the trigger is pulled. This
type of operation is used with a com-
pressor equipped with a tank or with a
Failure
large factory air system.
to install
Paint Tank – An auxiliary pressurized
paint reservoir that allows continuous
spraying of large amounts of paint with-
out stopping for refills as with a canister.
It also allows using the spray gun at any
angle without causing paint to drip.
Pattern Control Knob – Used to form
the proper pattern (size and shape) of
paint as it is sprayed from the gun to
the workpiece.
Pressure Feed – Method of paint feed
where a canister or paint tank is pres-
surized to force paint to the gun. Either
internal or external mix air caps are used
with this method. Pressure feed is gen-
erally used for spraying heavy bodied
paints or for large size projects.
Siphon Feed – Method of paint feed
where atmospheric pressure creates a
partial vacuum to siphon paint to the
gun. Only external mix air caps are used
with this method. Siphon feed is used
with light bodied paints.
Viscosity – A measurement of the
resistance to the flow of liquids.
CONVENTIONAL VS. HVLP
Conventional spray guns use a much
higher air cap pressure to atomize paint
than HVLP spray guns. This results in more
overspray and a lower transfer efficiency.
HVLP, electrostatic and airless processes
are currently the only compliant spray
methods that meet the strict 65%
transfer efficiency criteria required
by some air quality management dis-
tricts. This enhanced transfer efficiency
results in a significant material savings
compared to con-
ventional spray-
ing. Check local,
state and national
regulations that
may be in effect
before perform-
ing any spraying
operations.
HVLP spraying is
a growing trend
in the finishing industry due to its
environmental friendliness. By defini-
tion, dynamic air pressures in the air
cap must be 10 psi or less to qualify
as HVLP. A soft, low velocity pattern is
produced which increases control and
reduces bounceback and overspray (See
Figure 1). For these reasons, HVLP is
also well suited for spraying parts with
recessed areas.

Spray Gun Set-up

The pressure for atomization is controlled
at the air source. The amount of fluid is
adjusted by the fluid control knob, the
paint viscosity and the air pressure.
The gravity feed cup screws onto the top
of the gun body creating a positive fluid
pressure in the nozzle (See Figure 2).
Figure 2 - Gravity Feed Cup Set-up
Preparation
1. Thoroughly mix and thin paint in
2 Strain material through cheese cloth
3. Fill the canister about 3/4 full and
4. Set up a piece of cardboard or other
5. Test the consistency of the material
Conventional
FAN DIRECTION
HVLP
The direction of the fan (horizontal or
vertical) can be changed by loosening
the lock ring and turning the air cap 90
degrees (See Figure 3). Hand tighten
Figure 1
lock ring after adjustment.
2
Gravity Feed Spray Gun
Filtered,
Regulated
Air Source
accordance with the paint manufac-
turer's instructions. Most materials
will spray readily if thinned properly.
or a paint strainer.
start the air compressor.
scrap material to use as a target and
adjust for best spray pattern.
by making a few strokes on a card-
board target. If material still appears
too thick, add a small amount of
thinner. THIN WITH CARE!! Do not
exceed paint manufactuer's thinning
recommendations.