Re: Tractor painting?
I have to agree with professor (about 99%) and I was from the old school when it came to siphon style paint guns. Once I understood the transfer efficiency and timing between coats when using HVLP gravity feed guns, I never looked back at my other guns EVER. They are all boxed and probably retailed near $3K and most likely will be future yard sale items.
The industry made understanding transfer efficiency way too complicated and in laymens terms it's simple: Older style siphon/cup style guns (really, really good ones) had about 30% transfer effect....or 70% wasted paint in the form of over-spray and clean out. Newer HVLP guns are closer to 80% efficient like a SATA. $450. - and is not the gun I would recommend for the occasional user. My favorite, which is what I use when painting BPS paints is a $99. IR that I bought a Lowes. I can paint 2 1/2 times as much, with a single quart of paint with the HVLP as I can with the siphon style guns.
Valspar manufactures the BPS paint line. Doug Nash is the (my) area rep and has clued me in on what the directions on the can state, and what you can really get away with. Hardener is highly recommended in the paint and primer. Up to 50% more hardener increases the drying time, repairable in 24 hours, is chip resistant, fuel resistant, and I like this, you can pressure was the paint within 72 hours when fully cured. Is it as good as comercial automotive paints like Acrylic enamels, Urethanes and Poly urethanes....NO. But it is up to 1/10 the costs.
I occasionally see some of the tractors I painted about three years ago, and they still look very good considering they are used frequently, left outside almost always and seldom even washed.
I just want to say that I have no interests or affiliation with Valspar, just excellent results and it is very cost affective when you only need three components to make it work, Naptha (or mineral spirits when brushing), hardener and paint.