you can get a set of sponge-like applicator brushes ranging from about 1" to 4" wide at anyplace like home depot for about 5$. break a wooden paint stirrer longwise down the middle. duct tape it to the handle of the applicator--this gives you extended reach with the applicator.
The different size applicators work well in different parts of the frame--e.g., 1' applicator inside the frame rails. with widest applicator i was able to cover the inside of the rear tube crossmember with POR. the width of the applicator matched the diameter of the tube--insert moist applicator and rotate!
I used the applicators only in places hard to reach--the POR breaks down the sponge material pretty quickly. And it's a bit harder to spread to the POR evenly with applicator--so everywhere else brushes.
very pleased with the results, but ALOT of work. I used a pretty nice compressor paint sprayer to apply the POR chassis coat on top. much easier, coverage, and fantastic finish.
I was a little concerned that the chassis coat might gunk up the sprayer but it cleaned up well with laquer thinner.
Considering how easy it was to spray, I'd like to try spaying the POR 15 itself, but I am little concerned about ruining the sprayer. Has anyone tried this? If so, did you use laquer thinner to clean up afterward? All the equipment I use belongs to my buddy and I'm trying to be really careful not to damage any of it--especially seeing as he lets me use it free and whenever i like
Here's a pic-working on the inside frame rails: