IMPORTANT: Before using this equip-
ment, read all safety precautions and
instructions. Keep for future reference.
DESCRIPTION
The MBC-ZINC spray gun is intended for
use with the new waterborne, zinc rich
protective coatings. Solvent borne zinc
coatings can also be applied with this gun.
The MBC-ZINC has all the features of the
standard MBC-510 and consists of spray
gun body and removable sprayhead.
MBC-ZINC differs in the following com-
ponents.
Leather packings
Heavy duty needle spring
Delrin construction air cap
Delrin construction retaining ring
Fluid tip with composition insert
These components have proven very
effective in handling the unique charac-
teristics of waterborne zinc rich coatings.
By using these components, the user
will insure the longest and most reliable
operation before major repair is required.
HANDLING OF ZINC COATING
Some zinc rich formulations can require
up to 20 lbs. of dry zinc per gallon of
liquid. Care must be taken when adding
the zinc to insure complete suspension
into the liquid. Mechanical agitation
must be used when mixing, and during
application, to prevent agglomeration and
settling of the zinc particles. These larger
clumps will interfere with needle seating
and cause premature wear and leakage to
the tip or needle.
Zinc rich formulations have limited pot
life. Once the zinc is added, the liquid
slurry begins to increase in viscosity. Ma-
terial should be used within 3-4 hours after
mixing. If material is applied out-of-doors,
viscosity will increase faster as a result
of heat buildup caused by environmental
conditions.
Zinc solution – Follow manufacturers
directions for mixing zinc powder into
solution. Make sure adequate mechanical
mixing is observed during and after zinc
is mixed into liquid.
These instructions are found on both
container label and Technical Data Sheets.
In addition to specific recommendations
on handling the zinc, suppliers also have
recommendations concerning operating
pressures, air and fluid hose length
and size.
GUN OPERATION
The MBC-ZINC is supplied with a D (.086”)
size fluid tip. Extensive field testing of
the various zinc formulations conclude
that the use of smaller tip sizes require
elevated fluid pressures, which in turn,
increase the tendency of needle seat in-
terference. These higher fluid pressures
also cause the liquid material to pack out
when the gun is triggered off. Lower fluid
pressures help minimize both conditions.
After first mixing, a fluid pressure of ap-
proximately 15 psi should provide satis-
factory flow rates for normal production
speeds. A reduction in flow output will be
experienced as the viscosity increases and
fluid pressures will have to be increased.
Under most application conditions, at-
omizing air in the range of 50 psi will be
satisfactory.
Packing operation – The packing set con-
sists of 3, pre-lubricated leather packings.
Packing tension on needle is factory set.
Lubricate packings twice daily by add-
ing a few drops of •SSL-10 gun lube to
the needle shaft. Retain proper packing
tension to allow smooth needle travel.
This will insure minimal needle shaft and
packing wear.
CLEANING
The fluid hose interior and gun fluid pas-
sages should be cleaned immediately af-
ter each zinc batch is used. Exterior metal
surfaces of the gun body and head should
be wiped clean before any accumulation
is allowed to dry. Waterborne zinc in its
dried state will be extremely difficult to
remove from any metal surface.
The DeVilbiss air cap GTI-1-100L, is
constructed of Delrin . The zinc will not
adhere to its surface. If zinc is allowed to
dry, the film can be simply removed with a
fiber brush or by soaking the cap in water.
When the cap is removed, always wipe off
the fluid tip exterior surfaces to prevent
any zinc build up from drying.
Service Bulletin
SB-2-303-D
MBC - ZINC SPRAY GUN
PREVENTIVE MAINTENANCE
The MBC-ZINC spray gun is designed
to provide the user trouble free service
applying this unique protective coat ing,
with only minimal care and maintenance.
There are certain steps the user can take
to insure trouble-free service.
1.Never immerse or soak the entire spray
gun in any liquid. These liquids are
generally contaminated and can foul
interior components and passages.
Immer sion over long periods can also
dilute and remove lubricants necessary
for smooth operation. Lubri cate gun
components daily as indicated.
2. Mix dry zinc into solution using a me-
chanical agitator. Maintain agitation
during application.
3. Mix only the amount to be used in 4
hours or less.
4. Refrain from using excessive fluid
pressures. A range of 15-30 psi should
be satisfactory during the 4 hour pe-
riod of application.
5. Avoid longer than 25 ft. lengths of fluid
and air supply hoses to the gun. Air
hoses should be 5/16” I.D. minimum.
6. Do not allow zinc to dry on any interior,
metal fluid passage in the gun or hose
fittings. An appropriate cleaning agent
should be used to purge the system as
soon as a batch is used up.
7. Use a cleaning brush (see Accessories)
to clean the air cap. Do not use a wire
brush. Also avoid using metal objects
such as drill bits to clean air hole jets.
This air cap, unlike other DeVilbiss
metal air caps, can be damaged if
abused. Avoid using it as a chipping
hammer, etc.
•Material Data Sheet available upon request.
Replaces SB-2-303-C
Repair Kit KK-4058-1
