27
26
Adjusting the Material Flow Rate
The material flow rate can be adjusted by screwing in / screwing out the set screw
(Item 14). The material rate is increased by turning it to the left (screwing out) and
decreased by turning it to the right (screwing in).
Adjustment of the Atomizing Air Pressure
The atomizing air pressure is to be adjusted at the pressure reducing valve of the
compressor system. Please comply with the operating instructions and safety
warnings issued by the manufacturer.
If you wish to change the spraying pattern beyond the adjustments outlined so far,
the spray gun must be retooled (
see 5.5 Retooling the spray gun
).
WALTHER offers a great variety of air cap / material nozzle / needle combinations
for this purpose.
5.5
Retooling the Spray Gun
Combinations of air cap, material nozzle and needle, designed to match specific
spraying media type and grades, form a unit - namely the nozzle insert assembly,
which must always be interchanged as a complete assembly to maintain the desired
spray-finish quality standard.
Warning
Prior to retooling: Make sure that the spray gun is in unpressurized condition, i.e. the
air input must be shut off - if not, imminent risk of injury.
Note
Please use the exploded view at the beginning of these operating instructions in
order to perform the following procedures.
Replacement of Material Nozzle and Air Cap
1. Unscrew the retaining nut of the air cap (Item 1).
2. Remove the air cap (Item 2).
3. Unscrew the material nozzle (Item 3) from the gun body using a size 12 wrench.
Installation is performed in reverse order.
Replacement of Material Needle
1. Unscrew the adjusting screw (Item 12- 14).
2. Remove the spring (Item 11).
3. Pull out the material needle (Item 9) from the gun body.
Installation is performed in reverse order. The setting dimension for the needle- con-
trolled initial air input is 64 mm, measured from the point of the material control
needle to the needle retaining nut (Item 10).
5.6
Correction of Spray Pattern Imperfections
The table below shows what to do to correct a spray pattern.
Spray pattern
test
Fault
Required adjustment
Spray pattern is split in
the centre
• setting a wider spray pattern
Spray pattern is too thick
at the ends
• Setting a more rounded spray
pattern
The spray pattern shows
rather large droplets
• Increase the nozzle air pres-
sure
Material application in the
centre of the spray pattern
is very thin
• Decrease the nozzle air pres-
sure
Spray pattern is split in
the centre
• Increase the nozzle diameter
• Reduce nozzle air pressure
• Increase material pressure
Spray pattern is very
spherical
• Reduce material pressure
• Increase nozzle air pressure
6
Cleaning and Maintenance
6.1
Safety Instructions
•
Make sure that the spray gun is in unpressurized condition, i.e. the air input must
be shut off - if not, imminent risk of injury.
•
Open fires, naked lights and smoking is prohibited in the working area. There is
an increasing risk of fire and explosion, when spraying readily flammable media
(such as cleaning solutions).
•
Observe all processing specifications and safety warnings issued by the manuf-
acturer of cleaning media. Especially aggressive and acidiferous media repre-
sent risks and hazards to personal health.
desireable spray-painting result
