Tip: Stewart Systems paint comments

[Larry DeCamp]

Kyle Boatwright asked me to comment on my experience with Stewart. First, the paint was urethane not acrylic. Dan Stewart said urethane was recommended for fabric for flexibility. I used it on my RV because my brother in law was restoring a C140 in the same colors . I suspect urethane is more resistant to stains but have no data.
The primary reason for selecting Stewart was waterborne. Many hours of stumbling around with spraygun hose and hood hose shooting Imron and Stits Aerothane made this a no brainier. A simple Carbon mask from the home improvement store works. I used isocyanate catalyst in medical device products and challenged Dan at OSH regarding simple mask vs positive fresh air supply. He said the catalyst IS NOT isocyanate and becomes harmless as soon as it is mixed in the paint. If you select another waterborne system, you might investigate that. What might be good for environment may not be good for you.
The devilbis FP4 gun they recommend goes a nice job. You will spend several hundred dollars on big hoses and high flow regulator for HVLP supply. I have turbine for solvent that was fine, but Stewart says the warm air is bad for waterborne, so, more$ required.
I experimented with water dilution percentage and spray pressure to optimize the finish. Bottom line, with upper 20's pressure and follow the mix recipe, the finish comes out like a clearcoat factory automobile. I could not match Perry Testories ProShop finish (high $) or cut and buff ( DanH)!
I had a lot of problems with PINHOLES. Waterborne seems more sensitive Than solvent to coating weight, flash time and shop temp. Three coats look normal, the last "wet coat" can totally tun into pinholes😢This only happened on red and blue colors, never white. Also, the opacity of the paint is questionable. Red and blue over white primer Is very sensitive to film thickness. White color over gray vs white primer is noticeable. Auto paint is rumored to have more fillers and be less flexible, but perhaps more opaque?
I would use auto paint from my local supplier on a metal airplane😊