Why Your Spray Gun is Spitting

We often receive phone calls asking why a spray gun is “spitting”. Spray guns spit when air is being introduced into the fluid outside of at the air cap. Here will cover the most common causes and their solutions so that you can get your spray gun to stop spitting.

1.  Fluid Nozzle – The first area to check if your spray gun is spitting is the fluid nozzle. A loose fluid nozzle does not properly seat in the tip of the spray gun and causes air to enter the fluid supply resulting in spitting. To solve this issue properly tighten your fluid nozzle or if unable to tighten the fluid nozzle inspect the head of the spray gun to see if their is any stripping of the fluid seat or the fluid nozzle threading is stripped.
2. Air Cap Properly Matched – If you are using a siphon/ Suction Fed Spray Gun the correct air Cap is vital to being able to properly spray and not experience spitting. With a suction fed spray gun you have to use a suction/ siphon fed spray gun air cap and NOT A PRESSURE FED AIR CAP.  Siphon Fed Air Caps cause air to be drawn across the material allowing it to be supplied and sprayed a pressure cap will not create a suction effect resulting in fluid not being supplied to the spray gun.
3. Packings- If you have the correct Air Cap and Fluid Nozzle it might be your packing nut is bad or the physical packings are worn. Inspect the packing nut to ensure it is tight as well as the packings to ensure they are not worn or missing. If the packings are missing make sure to order new packings.
4. Fluid Connections- If you are using a pressure fed spray gun make sure your fluid connection is tightly applied to your spray gun.
5. Gravity or Suction Cup – If you are using a Gravity or suction fed spray gun make sure your cup is seating tightly into the spray gun. Inspect the threads of the cup to ensure they are not stripped as well as inspect the threads of your spray gun to ensure they are in good shape and not stripped. If either are stripped replace the cup or gun body if necessary (or buy a new spray gun).
6. Material is to heavy/ Viscous – If your using a suction fed spray gun your coating may be to viscous to be sprayed with a suction fed spray gun. If you want to use a suction fed spray gun to spray the material you can try increasing the fluid nozzle and/or selecting a higher CFM Air cap (which will allow for better draw of the material up to the fluid nozzle).
7. Air Cap Clogged (Suction Spray Gun) – Check your air cap to ensure that is not blocked by any paint, if it is clean it out using a cup of proper cleaner
8. Fluid Pressure to Low – If your using a pressure fed spray gun you may not be applying enough pressure to your coating to supply the gun appropriately. This often happens with very thin material like stains that you are trying to keep coating to a small amount. To remedy this try applying a little more pressure to the coating and then using your fluid adjustment knob to restrict fluid to the spray gun.
9. Fluid passage clogged – Clean the fluid passage of your spray gun with an appropriate cleaner to ensure no particle has become lodged in the spray gun due to sitting for a while or a partial hardening of material. If this is a recurring issue consider adding a fluid filter to your pressure pot or straining your material prior to spraying appropriately.

By checking these 9 things you should be able to fix the problem with your spray gun spitting. If you need further help were always available to help troubleshoot your spray gun problems.