Can I Use Latex Paint in a Spray Gun?
Can I Use Latex Paint in a Spray Gun? Yes with the Right Setup
People often wonder if they can spray latex with a spray gun as it is a heavy bodied material and you may be concerned it will not be able to be applied. The good news is you can spray latex paint and in this article we will cover what you should consider to do so .
The Right Type of Spray Gun
You can Spray Latex with an HVLP or Conventional Spray Gun. However, if your using an HVLP Spray Gun you will need to use a high CFM Air Cap. The CFM of the Air Cap with an HVLP spray gun determines the ability of the spray gun to atomize heavier coatings. So if you are going to use latex you will need the highest CFM air Cap that you can have for the particular spray gun your using. If you are trying to use a low cost spray gun it may not be able to handle latex (it will depend on the CFM that the air cap is designed to accomodate). You will not be able to spray latex well through a low CFM air Cap with an HVLP Spray Gun. A Conventional spray gun will allow you to be more likely to spray latex coating with a smaller compressor but will not have good transfer efficiency which can be costly. In addition to the way you atomize your coating you will also have to consider how the coating is supplied to the spray gun. Since latex is a thick coating, you will want to consider a pressure fed gun. You can spray it with gravity but will require a heavy amount of thinner which will require more coatings to get good coverage and can result in a lot more waste., With the gravity or pressure fed spray Gun you will want a large nozzle (at least 2 mm or bigger).
The Pressure Pot
Latex is a water based paint which means there should be a few things to remember about your pressure pot. If you will be spraying only latex all the time you may want to consider a stainless steel pressure pot. A typical pressure pot is made out of galvanized metal and will corrode if water based coatings are left in over long periods of time. You can solve this by using a stainless steel pressure pot or by not leaving coating in the pressure pot and using a pressure pot liner when you spray water based coatings. It is important to remember that if you used a latex paint and clean your lines with water if you switch to a solvent coating you will want to flush the fluid line with solvent before beginning to use a solvent based paint, otherwise you will have a reaction between the water and solvent coating resulting in a cottage cheese appearing coating.
Adjust the spray Gun Appropriately
To adjust the pressure fed spray gun there is a tutorial here where latex paint was used as the coating that covers how to adjust the pressure pot for your coating. Essentially you should expect to use a fairly high amount of fluid and air pressure to atomize the coating. Remember if your using an HVLP Spray Gun and providing it with more psi than written on the air cap you will not get the transfer efficiency that the gun is designed to provide.