POR-15 or similar

I have the box off this ford ranger I've got in the garage, and besides the other work I'm doing to it, I'd like to deal with the flaking rust on the frame, it has it's first layer of scale, but if left as is, at some point it would probably be well beyond saving. Either from the salt and or moisture, it's sat awhile, on gravel, the top side of the frame seems to be the worst, but plenty of metal left to work with now just being the first layer of rust scale, seems doing some cleaning and removing of the scale, cleaning, wire brushing, (a needle scaler might be the next tool on my list), a product like POR-15 should be a good selection to coat this frame and protect it from further rust, the truck only has 70,000 miles, has the 2.3L 4 cyl., and 5 spd, if left as is, the rust would probably do the truck in before the drive train was wore out. Just wondering what may be a good product to apply after doing the prep work, POR-15, or equivalent, heard napa has a similar product, a friend used it, yet he's seeing some rust re-appear, as always appreciate your suggestions and advice, thanks !

Billy: I"ve used POR-15 on truck frames with good results. I"ve been VERY impressed with it wherever I"ve used it, provided you follow the directions. The stuff is unbelievably tough--I"ve applied it and then hammered out dents (not by choice, the dents magically appeared after application....) without cracking the finish. Below is my 1956 Chevy truck with POR-15 on the frame. POR-15 flows out very well when applied with a foam brush (or actually several dozen foam brushes!), though if you"re worried about looks you"ll want to topcoat it--POR-15 will lose its gloss and turn grey if exposed to long-term direct sunlight.

How much did you use to coat the frame ?

Foam brush - best applicator, how did it apply with a bristle brush ? I can imagine that this is not something you want to get on your skin.

I read up on it and saw the information about the topcoating/sunlight, and the metal preparation work. This does not have to be aethestically perferct, there is lots of pitting, whereas one could really fuss, use filler and attempt to make the steel look smooth again, I just want to try and protect the frame so that I can get the use out of the truck, 1st service truck for my business, would be nice not worry about the spring shackles rotting off as is common to these if not taken care of, fortunately it's not near that stage, but would not take long if I don't do something now, thanks for the photo !