HVLP Spray Gun Troubleshooting A Complete Guide
There are a variety of benefits to HVLP over Conventional Spray Guns like reduced paint waste and when applicable being approved when emissions reduction is a concern. However, HVLP can also take a little more getting use to as it is not quite as simple as continuing to turn the air pressure higher until you get the desired paint finish you need, turning air pressure higher and higher can end up ruining the efficiency gains from the gun. This article will cover common HVLP spray gun problems and what you can do to fix them.
HVLP Spray Gun Problem 1 – My HVLP Spray Gun is not providing a good finish, my paint appears chunky or uneven (Orange Peel)
If you have problems with achieving a smooth finish when using HVLP it is one of few problems. First is whether your paint is thin enough to be able to be effectively sprayed with HVLP Spray Guns. Ideally, paint will be between 20 – 30 seconds in a Zahn 2, this is a sweet spot for HVLP spray guns to be able to effectively atomize the paint without excessive. You should check your technical data sheet for the paints you are spraying as they will often specify if they can be sprayed with HVLP spray guns. If the technical data sheet doesn’t specifically state HVLP spray guns will work it may be to viscous or have to high of solids and viscosity to be able to spray. If your coating can be sprayed HVLP you may have to add thinner to the highest amount that is recommended by the coating manufacturer though it can be better to start with small amounts and add more over time.
If the coating is thinned to the manufacturers maximum recommendation or is sufficiently thin according to a Zahn cup reading and you are still not getting the finish you need the next thing to consider is your air compressor and air cap. HVLP spray guns require high volumes (CFM) of air from your compressor. Most compressors bought at a hardware store are 9 CFM or less and so a lot of times will not be sufficient enough to supply your HVLP spray gun air cap with the air it needs. You can check your compressor to determine the CFM of air it will provide. While there are options for low CFM air caps for HVLP Spray Guns you may find that they do not provide sufficient break up of your paints. If you have enough air for your HVLP spray gun you can evaluate whether there are different HVLP Air Caps available for the spray gun. As a general rule an air cap with a higher CFM rating will provide better break up and reduce orange peel in comparison to a lower CFM air cap. You can also talk to a paint equipment company like us for additional help finding an appropriate HVLP air cap for your spray gun. Or read more about air cap selection here.
If you are using a pressure pot spray gun with your HVLP Spray Gun you can also consider adjusting the pressure pot settings. If your paint appears chunky you can try reducing the amount of paint by decreasing fluid pressure or increasing air pressure to break up the paint. If your fluid pressure is below 12 pounds on the pressure pot or cup consider making adjustments first to the air if it is above 12 you can consider lowering fluid pressure first.
A final way to fix paint that may be to chunky or uneven or has orange peel when spraying is to consider changing the fluid nozzle. If you are getting orange peel when painting considers selecting a smaller fluid nozzle or choking the fluid needle on the spray gun in. Both will help reduce paint but choosing a smaller fluid nozzle will be more effective at reducing the amount of paint to air and will provide a better result of giving you a good appearing finish with less orange peel.
HVLP Spray Gun Problem 2 – My Gravity Gun is not getting any paint delivered to it
If you are using a gravity feed HVLP spray gun and not getting any paint in your pattern this is most likely due to needing to thin your paint, needing a larger fluid nozzle, or needing to use a system that will force the material to the spray gun like a Dekups cup option. If you have a filter in the gun it may be to fine of a screen and as a result may be over thinning your coating.
HVLP Spray Gun Problem 3 – My HVLP spray Gun is Spitting and Dripping
If your spray gun is spitting it is most likely because your fluid nozzle is not tight. Or if you have tightened your fluid nozzle but the gun is still spitting or dripping it is probably due to your fluid nozzle and fluid needle being worn out and needing replaced.
HVLP Spray Gun Problem 4 – My spray pattern is different on both sides
If your spray pattern is inconsistent you may not have enough air or if the pattern stays in consistent when flipping the cap from one side to another, then the air cap is probably worn.
HVLP Spray Gun Problem 5 – My spray gun is leaking air around the handle
If your gun is leaking air around the handle your guns soft seals are most likely worn. Quality spray guns have rebuild kits that include all the soft parts like washers that when replaced will stop the gun from leaking air around the handle.
HVLP Spray Gun Problem 6 – I am not saving paint
If you are not saving paint compared to conventional spray guns you probably have your air pressure set to high. You can learn more about HVLP and proper air pressure settings here.
You can call us if you need further help with your HVLP spray gun.