Gun Setup for 100% Acrylic Paints
A few simple tips for spraying paint. September 16, 2008
Question
What is the best setup for latex, as far as cup guns go? What is the best size tip, and what should be a starting point for reduction? I am spraying Pro Classic, and do not want to change the sheen, and do not wish to use the airless for small jobs. I am wondering what others are doing for these?
Forum Responses
(Finishing Forum)
From contributor A:
Thin and spray with a brand new $35 gun from Home Depot.
From contributor B:
Pro Classic (Sherwin Williams) is not latex. It is one of the newer 100 % acrylics. I am well aware that the term latex has referred to many things in our industry. It actually refers to the chemical structure of the liquid versus actual latex from a tree. But the Floetrol additives are not used with these products (ProClassic, Muralo Ultra). Simply use distilled water in small amounts not exceeding the can's directions or about 5% of volume.
As for a gun most of the cheaper HVLP gravity guns sold at Home Depot or Lowes or online from reputable companies will shoot the acrylic topcoats nicely. We typically use 1.7 n/n set on a gravity and 1.5 n/n set on a pressure pot system. Make sure you stir the water in for about a minute. This also helps to get all of the surfactants and defoamers well mixed into the solution.
From contributor C:
Use a pressurized cup gun or turbine hvlp with a pressurized cup. Gravity or bottom feed is fine - make sure it has 5 psi of pressure feed. Tip size should be 1.8-2.2mm so you don't need to thin more than 5-10%. I use a 3 stage turbine for onsite stuff with a 1.8 mm tip and a pressurized cup. I thin my waterborne enamels (100% acrylic 45% solids) about 10% to get really nice atomization and good leveling.
From contributor D:
Use plenty of air.
From contributor E:
With the Pro Classic you will be better off with airless. They list the fine finishing tip and thinning information right on the can, or at least they used to. It is .011 for airless I think and you can definitely go up in size if you want heavier application. I've used .012-.014 or even .015. Sherwin Williams also has online data sheets for their products, and they're not recommending HVLP for this one. With HVLP you could thin 10% but you are going to need a good rig to get good atomization. The nice thing about this product is it dries much better than regular latex for handling on a spray rack etc.
