Spraying Paint Primer with a Cup Gun

A cabinetmaker has trouble spraying paint primer with a cup gun. Advice: either switch guns or switch coatings. August 29, 2006

We have done several painted kitchens and have trouble spraying the primer. It is from Mohawk and it is very thick. We thin it down but still have trouble. We normally use a pressure pot with CV but we have been using a cup gun with the paint and primer. The problem is it is just too thick to spray, and it just throws a very small pattern. I am thinking that maybe a gravity gun would be better?

Forum Responses
(Cabinetmaking Forum)
From contributor A:
I doubt a cup gun will help with your problem. All spray guns have a maximum viscosity that they will work with. Most gravity feed cups are around 25 seconds measured with a #4 Ford viscosity cup. Your only option if you choose to use these guns is to get a large needle/nozzle set (1.9-2.1mm) and to thin your product, while using more than the recommended coats to obtain the desired final mil thickness of the primer.

From contributor B:
I can tell you a gravity gun won't do it. I tried spraying acrylic latex with my Accuspray Isaac and even thinned out it was lousy. My neighbor, who is a custom car builder, gave me an old pressure gun he doesn't use anymore - a Mattson. It is kind of fussy to work with but it really shoots that thick stuff.

From contributor C:
Why not just use pigmented conversion varnish?

From contributor D:
Why not just use a standard airless paint sprayer?

From contributor E:
I know you may not want to hear this, but you may want to get different applicator for your paint grade projects. Check out the Kremlin system. It will make your finishing virtually effortless once you become familiar with the system. Drop your feed tube into your material and shoot slick coats every time until you’re tired. I have two now, one for colors and one for clears. I was reluctant, but now I am convinced that I could not be in business without one. If you can't handle it financially right now, switch from Mohawk to Sherwin Williams. Shoot a vinyl sanding sealer with your cup gun. Thin with approximately 25% lacquer thinner, and shoot. Sand with sanding sponge and set up for your top coat. SW will match, or offer, perfect colors in lacquer. Mix with about 25% lacquer thinner in your cup gun, and some retarder (butyl cellusolve 10% maybe). This is something that has worked very well for me before my cabinet business took off. However, there is no substitute for the Kremlin.