(10-27-2020, 08:06 AM)rwe2156 Wrote: @John,
What is the maximum you will thin a latex paint?
Have you ever used anything other than water? I've heard about windshield washer fluid.
I had to thin SW's ProClassic 18% to spray it with my 1.8 mm N/N gravity feed gun, back before I got the pressure assisted gun. It worked, but it's not something I would want to do regularly because it tends to run more easily which is no surprise. It doesn't look quite the same either though I'm hard pressed to explain in what way.
When I have to thin stuff I typically start with plain tap water and 3% of BM's Extender, using enough water to get the viscosity down to 300 seconds or less. Extender can make a marginal spray pattern look very good in about 5 minutes because it lets it flow out more before setting up.
I've never heard about using windshield washer fluid to thin a waterbased paint. I have no idea why that would be a good thing. Extra surfactants and alcohol don't seem like things I would want to add. For sure I'd try it with a small batch on a test panel if I did want to evaluate it.
Paints that have sprayed best for me are ones that are an oil emulsion - BM's Advance and SW's Emerald Urethane Trim paint. Both spray well once I thinned them to 300 seconds and flow out beautifully. The Emerald Urethane Trim paint dries a lot faster and that's the one I now use most. And there are other ways to get an opaque finish besides using paint. Both GF and TC and Lenmar sell pigmented WB lacquer products. They have viscosities less than 200 seconds and can be sprayed with a gravity feed gun with a little thinning, although a pressure assisted one makes the job easier. Maybe it's just symantics, paint vs. pigmented lacquer, I don't know. But the lacquer products seem to have lower viscosity and spray more easily, probably because they are targetted for spraying whereas paint is formulated for manual application or airless spraying.
FWIW, Lenmar's Duralaq-WB White lacquer sprays beautifully with my pressure assisted gun, as easily as most clear coats, and looks gorgeous - like it came out of a factory. And it can be tinted to a whole range of colors, too.
John