Have used POR 15. Not easy to put on because it stays on your skin for weeks. Don't wear short sleeves, shorts, get in your hair. I would'nt put in a spray gun,so brushing it is the way to go. Good gloves, long sleeves,hat. Works well, stays on. Need Tie Coat Primer to top coat if it dries. Instructions say to apply top coat when it has a slight finger drag. Hard to tell when that is. Had couple of places where it peeled up, probably the time between coats. but it really stays. Sanded them with 220 grit and re-applied. I like the idea of spraying it on, so next time I might try something else. If you use the POR, keep laquer thinner to clean off your hands quickly, leave a few minutes and it will stay. Some guys like the Eastwood stuff. I found Nason's chassis paint and may top coat the POR on the Civilian frame. Just to make it look more factory. I scotch brighted the wheel wells on my son's Jeep and herculined the wheel wells, POR on the frame has held up well, lots of off-roading, doesn't chip but did flake off where a big rock bent the skid plate but that doubled over the metal. Since it dries faster in moist environments, drying time changes.
Got my fuel tank repaired and they put on POR. I used tie coat primer and sprayed Gillespie. Worked fine.
Each time I do it it gets easier.
Last time I used Pickle -X 20, sprayed some rust bullet type stuff, then epoxy primer and Gillespie paint.
M274 A5 Mule (Pepe')
97 TJ Wrangler (Son's Ride)