Automotive Restoration Training Basics

Being HVLP and low VOC products are the way the industry's going I will be referring to them in this discussion on painting and paint guns. Most all Automotive Restoration Training basics dealing with HVLP can be applied to conventional guns, atomization is atomization. The HVLP just arrives at it differently.

The object of the spray gun is to break up the primer/sealer/paint/clear (I will call this "PSPC" from here out) into small particles and lay them in neat little rows on the panel being PSPRed. So the whole outcome rests on how well the gun is doing this. Picture the droplets of PSPC coming out of the fluid tip of the gun and then the air "slapping" them into smaller droplets.

You have two things that help you with this process, air and solvent. Solvent can mean something that is already in the PSPR from the manufacture or something the manufacture has told you to add to it. By the way, you should always mix in proper ratios as instructed in the tech sheet. The thinner (less viscosity) you get the PSPR or the more air you have at the fluid tip of the gun the more it will break up the PSPR. The target for you is getting the perfect balance needed. Too much solvent and the PSPR will have no body, fill, durability, etc. Too much air and you blow the PSPR everywhere but the car, poor adhesion, excessive texture, etc.

So, the answer is proper air supply and gun (and fluid tip) choice and how you adjust it.

With today's high solids-low VOC (Volatile Organic Compound, you know the bad stuff that goes up into the air we breathe) products there is less solvent. And with HVLP guns there is less air at the cap to break up the PSPC, proper air supply and gun setup is more important than ever.