Spraying oil into the frame once a year is a lot more human attention than I expect this idea, properly executed, to need. The idea is to seal it up and never have to go in there, but keep my options open (bolted covers) just in case I do.

Ok, so the gauge idea's a little silly... but duplicating the corrosion-resistant construction of axle housings and rocker panels just makes sense to me. My time costs a lot less than that of Japanese factory workers in the early 80's, and I care about the longevity of this truck a lot more than its average new purchaser. Sure, rusty hulks can be revived, but at what cost?

Paint? I've smelled some three-part topcoats and wished I hadn't, and I hear that POR, while relatively benign in liquid form, is pretty nasty in sprayed form. Molten zinc is dangerous to handle wet, but it's also expensive, and not a DIY thing by any means.

 

^ This.

I like your intentions, but what happens when you don't drain an air tank for a while? It rusts from the inside out. How would a pressurized frame be any different? The only way to eliminate moisture inside the frame would be to get it completely dry, put it under a vacuum, and rely on it having ZERO leaks.

There are much, much better ways to prevent rust.

 

Really just don't see it being worth the trouble. To do this you are removing everything and pretty much in a good position to just repaint the frame.

Although you have a a lot of ingenuity going on here. But I think it would be better spent if you were to build a submarine.

 

have you found any examples of this being done, say by a car/truck maker?

just have a custom frame built out of stainless..probably easier..

 

Not for a frame. But like I've said, for pretty much all rocker panels and axle housings.

 

You will have to TIG weld eveything to make absolutely sure you got it air tight. TIG it and after each pass spray some soapy water on on the seam or weld.
Seems like a good idea. I would coat the inside of the frame with some kind of rust inhibitor like you said.
Hope that helps

 

TIG is not the only way to get a sealed weld. Although it is much easier to.

 

Yes, many makers have built solid, sealed frame vehicles, but that does depend on your definition of "maker"
http://www.pirate4x4.com/forum/attac...?postid=615819

I had thought those joints running the length of the frame were welded solid, and they aren't, which would be quite a bit of welding to seal up. Still seems like if you had the frame off you could do everything here in a few days of solid work. Getting to that point is the hardest (or most time consuming anyway) part. I think it's a good idea that's easier and cheaper than most of the alternatives that have been floated, and I'd like to see it done for proof of concept if nothing else. Maybe then, someday when I'm doing a frame-off resto...

 

I don't have TIG welding equipment, nor have I ever used it. I do intend to make a proof of concept with some plate steel, and I have a sort-of spare truck identical to mine to practice on.

One thing that appeals to me about this idea, all the uncertainty notwithstanding, is that it'd be relatively easy to reverse: just drill out the small holes again, remove the bolt-on covers, and I'm back to square one. Painting the inside with some kind of coating, on the other hand, will be nearly impossible to reverse.

The bed's already off, and the cab is coming off for painting the outside of the frame, if nothing else.

 

Neat samuria, but nothing to do with sealing a factory frame

Gedrven, given your circumstances and my criticism I say go for it. Lot of work, but It definitely could prove to be affective. Although I still think its a lot of work for what your after.

 

You would need to purge the frame of any oxygen so that it cannot continue to rust, so you would need air tight welds. Really not worth the time.

IMO, a coating is definitely a better way to go. It's also possible to recoat in the future. If you try to seal it up and fail to purge it completely, you'll more than likely have some moisture in there too. Then you'll just have a frame rusting from the inside out and you won't even be able to see it happening, until its way too late.

 

Sure it does, it's one of many rock buggies, which start as tube steel open to the air and are welded shut, full of ambient air, without experiencing any issues related to having a sealed frame.

 

Here's yet another corrolary idea: turn the whole frame into one giant oil sump (or several, maybe one per side), with drain and fill plugs. The upshot is that it wouldn't have to be perfectly tight, just enough to meet subjective cleanliness standards. I check the oil periodically, it'd be a lot easier to add than having to spray it in with a snake thing, and to spread it around all I do is go for a bumpy, hilly ride.

 

That could work. You don't want to actually fill the whole frame right? Cause thats a lot of weight. But you could put used motor oil in there. Just a gallon or so.

 

I do still think it would be a lot easier to "fog" the inside of the frame with any black paint. You could just rig up a paint sprayer. Do that every couple years, would be impossible for rust to start. You would have to do the spraying with the frame dry of coarse, preferably in the summer.

 

so once you have this rust proof frame, what is your plans for the body? drivetrain? fasteners?
seems like your might be money ahead buying a landrover...

 

 

Except for the cab, variously paint or ignore them, let them rust, because they're 1. replaceable, and 2. not hollow, so they rust only from the outside and are much easier to clean up. As for the cab, the rocker panels are the only "hollow" part I have to worry about, and they'll be fine with their rubber plugs. Otherwise, the cab bottom is getting some paint for sure, probably the same thing I use on the frame outside.

 

Ok, I done some testing... I can't make a watertight weld with the equipment I have. I get water slowly seeping through the seams. Now, if I paint over the welds with several coats of paint like I'm going to anyway, I bet that'll seal it up properly, but I don't know if it'll last, with several heat cycles expanding and contracting the air and maybe popping some of the "paint seals". Or if I go with the oil sump idea, I don't know what long-term effect the oil on the inside will have on the paint layers on the outside. Ideas?

 

I don't know why no one has suggested a waxoyl treatment?
http://en.wikipedia.org/wiki/Waxoyl - Maybe it's not that common in the states?

Waxoyl is a rust preventive treatment, not a cure. You do not want to apply this over rust!!

In Denmark, where I come from, rust is a real issue due to climate and road salt, especially rough on old Toyotas!
My '91 4x4 Pickup (Hilux) Diesel with 276 miles has been "waxoyl'ed" from new, including inside the frame. However they use a thinner waxoil on inside/hollow compartments (You can get tubes with special nozzles for spraying inside the frame). I use another brand, not waxoyl, but I think they're all basically the same. Be sure to get the "black" stuff (looks better, IMHO)

You can apply this with compressed air, or directly from rattle cans. But wear protective gear, it ruins clothes, eyes and is nasty sticky. But as with paint, it's all about the prepwork. Spray on clean paint, not surface rust.

It may be a problem with serious offroading, as mud sticks to it. Hasn't been a problem on mine so far (with 21+ years!), but mine is mainly for on-road.

If you have both the bed and the cab off, then you could sandblast the rusty parts of the frame, apply paint and then waxoyl. You will regularly need to apply it, as it can dry out, and "crumble" over time (years?). I do light touch ups once a year.

Last year, when I brought my truck to the MOT, it failed because they couldn't see the VIN number on the frame (due to the thick layers of waxoyl). I got home and scraped the underseal off the frame where the VIN was located with a piece of plastick, and beneath the thick sticky stuff, the VIN was revealed on shiny factory paint!

Best regards,
Kenneth