A good spray pattern indicates that the coating is distributed evenly on the substrate. Several techniques help determine the quality of the spray pattern and the quality of the finish:
The lowest pressure needed to achieve a solid cross section as shown to the right should be used. This avoids overspray and ‘tails’ to the spray pattern. If insufficient pressure means you can’t get satisfactory fan pattern, use a tip with a smaller orifice.
Aiming the Gun
The gun should be aimed at the substrate from 10-12" away, ensuring that the tip is always aimed parallel to apply an even coat. For an even finish, avoid tilting the gun up or down or fanning it side to side.
Moving the Gun
The timing of trigger activation and release and movement of the gun is shown to the right. The trigger should be pulled once the gun is in motion otherwise a heavy coat will be applied at the point the trigger is pulled before it is moved across the surface.
Maintenance and servicing
The most common cause of downtime for a spray machine is due to paint clogging the internals of the machine – follow these pointers to ensure downtimeis reduced to a minimum:
- Before spraying, be sure to check that all filters are clean
- Ensure that all connections are tight and the hoses are intact and free of kinks or other defects
- Never leave paint standing in the machine for more than an hour
- Always add a few drops of throat seal lubricant to the packings before spraying - this reduces wear and tear from the piston
- Perform a final flush using pump conditioner - this prevents the intake check balls from becoming stuck in their housings which can happen when water alone is used
- Packings should be replaced before the packing nut cannot be tightened any further
- Tips should be cleaned with a soft brush and dried thoroughly before storage
- Tips should be replaced once the fan pattern begins to degrade
Spray machines will eventually require a service where all components of the machine will be examined by the manufacturer as not all parts are user serviceable. At a minimum, this should be done annually, however the frequency is dependant on the volume and type of paint being sprayed through the machine. A general guide is below: