I don't think POR is the right stuff for the inside, it is not resistant to gasoline. According to POR you only have to remove "loose" rust but IMHO I would at least wire brush it to get as much off as I can before using the product. Using stuff that you "slosh" inside the tank doesn't work all that well when you have partitions and baffles. One professional shop cuts the top open so they can get inside to repair any leaks and then they brush the inside with sealer before closing it up. Because of the history on the fuel tanks I would have the tanks sealed inside. Too much work to get them back out when they leak. A quick look in HMN gets Elizabeth Radiator elizrad.com and West York Radiator in York PA.I pulled my tanks now and luckily there is only one spot that's in rough shape. My skills are more around mechanical rather than painting, sealing, stripping, but I'm always trying to become more competent so let me ask some detailed questions since I'm not sure I understand the tactics you guys talk about.
I don't know much about POR except what little I just researched. I thought it was a paint-over-rust product, but it seems like you have to go through a process to clean any rust off first? Also some people say it doesn't bond well unless it is/was a rusty surface. Is that true? I expect I'd have to strip the paint off the tank and then POR the outside, as long as it works well with clean bare metal. What's the best way to strip the paint?
How would you POR the inside? With the vertical separater it would seem difficult, but I assume you dump in some amount of the product (for the 3 stages) and slosh it around? You won't be able to spray off the degreaser/etcher steps though? Is sloshing around water good enough for those steps?
Someone mentioned powder coating tanks to me, but I didn't see any comments here to do that so is that flawed in some way?
I'm sure it's probably best to get somebody else to do this, but if I did that I wouldn't be able to do any of the stuff I do currently. And I'd probably have no money left either. So I'm looking to give it a shot. How bad could it be.