When I start the rebuild of my truck I want to make it as rust proof as possible so hopefully it stays around for a few years. I'm going to go with stainless steel brake lines to replace the standard ones, steel braided lines to replace the flexible sections, I'm going to use urethane bushings wherever possible. and I'm going to go ballistic with undercoating on the body once sandblasted.
The area of contemplation is the frame. We know that these boxed frames rust out here in the Northeast and basically turn the trucks into junk, so I'm going to have the frame powdercoated by a shop close by. As good as powdercoating is, it only covers ONE side of the boxed frame, the outside, but leaves the inside of the rails exposed to the elements and rust. Rust happens with moisture and oxygen, and if you can stop oxygen from getting to the part, it won't rust. This is the same theory that POR15 works off of.
Once the frame is powder coated, it is still a hollo tube that could be sealedoff enough to be able to fill with a liquid plastic or rubber to prevent oxygen from getting to the metal, esentially encasing the rails away from oxygen and the elements. Would doing such a thing drastically effect the handling of the truck ? I know frame flex is needed for road ability, and seeing as how neither plastic or rubber are solid substances and would allow SOME flex. what do you think could happen to the truck ?
Remember, this is just a theoretical conversation, so please speak up with any ideas or suggestions because they are ALL welcome. I'm just trying to work out a plan for the whole truck before I attack it.
Much Thanks

Just tell the powder coat guy to shoot inside the box. It will cover the hole inside. By the time it rusts out you would probaly have found another frame and have restored it by then. If you realy wanted to slow down rust then send the frame out to a place that does galvinazing. Now that is somthing that no one has done yet.

Im pretty sure no has done it cause not too many people thought about it. So you are thinking about Powdercoating the outsides of the frame rail and filling the insides with something like plasticoat? I used por15 a lot a few years ago and the stuff works. Kinda pricey locally. The plasticoat stuff goes on nicely but can be pealed off like elmers glue off your hands. Someone on dsmtuners painted his whole car with the stuff.

The galvanizing idea is something I never consider, but it is interesting. I would have to find a shop that could submerge a 15' long frame (roughly). I live in NJ, it won't be too hard to find someone willing to play with chemicals.
...and I looked already, some places CAN powdercoat on top of galvaning, so I could even make it all fancy.
(I'll be chasing bolt holes with taps for a few weeks, but, whatever)

When I redid my 1980 D-50, I had the frame sand blasted, then sprayed it with original DP40 (lead-based), then primed and painted it with Ronan Magenta sign painters paint(also lead based). !9 years later, the color has finally bleached out in spots, but NO rust anywhere. Keep in mind, I live in Pittsburgh, but the truck no longer sees winters. I do drive it in the rain though. My original frame did totally rot through from the inside out in 12 years; I daily drove it then.

Galvinizers are easy to find. Look in the wellow pagers. There is not that many of them left because of the EPA. So it's going to be a realy big company. At least thats all we have left in California. It would be best if you could find one and go there talk to some one, get a tour of the place and tell him about your project. You would probaly get a better job that way. It would break up the monitney of the work for the employes.,
water pipe, water pipe, water pipe, fence poast, fence poast, fence poast, Car Frame? Realy? OK. water pipe, water pipe, fence poast.

Haha. Bet that would stump them.

you could always sand blast it then use something like Linex or Rhino Lining. Its sprayed on so the inside of the frame could be done too. just an idea