Common air paint spray gun problems can be easy to identify if you know where to look.
Test any paint spray gun with a thin solvent or water before spraying paint to identify any faults and reduce wastage and mess.
Incorrect adjustments could be one of the most common problems when using an air spray gun for spray painting. Refer to our article describing how to set your airless spray gun prior to spray painting.
If you are not sure which spray gun adjustment is causing the problem it is best to start with all settings at minimum and slowly increase each control until the desired spray paint pattern is achieved.
Too high air pressure or even unregulated compressed air pressure is a very common problem which causes high levels of over spray and very poor transfer efficiencies.
If the paint spray pattern of your spray gun is uneven there are several checks you can make visually, although a magnifying glass may help identify certain faults especially with very small setup spray guns.
A common cause of uneven spray patterns is the air ports in the air cap accumulating a build up of dried paint which restricts or blocks these air atomisation ports completely. Carefully inspect each port, holding the air cap up to the light may help to identify if a port is blocked or open and take care cleaning these ports in your spray gun air cap as any damage may require replacement parts to rectify.
Soaking your air cap in thinners can help clear these air flow ports and reduce risk of damage but take care not to expose the nylon retaining ring that holds your air cap assembly together to solvents which may damage or soften this nylon retaining ring.
If your air cap ports are blocked with a two component paint a more aggressive solvent or sonic cleaning may be required.
Remove the fluid adjustment knob from the rear of your spray gun and with the majority of air spray guns this will allow you to remove the needle return spring and the fluid needle by drawing a backwards out through the body of the spray gun.
Inspect along the angle at the tip of the spray gun fluid needle for any steps or grooves that have worn. Slowly roll the fluid needle from your spray gun on a flat surface while carefully watching the tip. If the fluid needle is bent it will be easy to spot the bent fluid needle tip oscillating as you roll it backwards and forwards.
Remove the fluid nozzle from the spray gun using a suitable spanner. Ensure the spanner used is a good fit as the fluid nozzles can often be very tight to remove and an ill fitting tool will simply damage the flats on your spray gun fluid nozzle.
Hold the fluid nozzle to the light and while looking through it should be concentric. It is quite common to see fluid nozzles from paint spray guns which have been dropped where the fluid nozzle has been bent on contact with the ground. An out of round bent fluid nozzle will require replacement.
Bent or worn fluid needles also require replacement and if the fluid needle is being replaced it may be worthwhile obtaining a new fluid needle packing to fit to your spray gun at the same time.
Generally the cost of a fluid needle, fluid nozzle, needle packing and air cap for most quality air spray guns will begin to approach the cost of a brand-new replacement spray gun.
it is always a good idea to check the cost of a new spray gun against cost of spare replacement parts partsand any spray gun service centre labour costs.