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I have a solid,fairly straight 1952,M38 tub.I have an N.O.S.front floor,hat channels and firewall all complete.It seems as though there is rust between all the panels on this tub.Under the dash,the seems all have a little rust.Would it be too big of a job to completely disassemble(drill every spot weld)?? I would hate to install the new floor ,weld up a few holes,knock out a few small dings,paint it and in a couple years have rust pop out at the seams.Has anyone else run into this problem?? Any advise would be greatly appreciated. I ain't scared of it,just wondering,Take it apart, or treat the rust?? Thanks,
Stick

I think that is pretty common.

Most of the seams on mine were not too bad so what I did was use paint stripper and wire brush the intersections to clear out paint and prayed phosphoric acid into the seams. I've found that phosphoric acid works best on lite rust.

I use Etch & Prep from Home Depot and I use it undeluted. You have to go over everything a couple time then rinse with water.

This is a tough call without seeing the tub but I'll add my 2 cents.

Unless the floor is rusted out with holes I would try 53A1's approach first. From a conservation standpoint a mild approach would usually be the first method. I like the DIY aspect as it gives you some control over the strength of the acid.

For the ultimate in rust removal find a shop that does electrolytic rust removal on car bodies. This method will remove all rust including inside hat channels and seams or joints. Acid baths are the next step down. With the DIY method last. Sand blasting won't really do what you need if I am following your problem description.

There are also rust converters that are very simple and appear to be effective.

When all these individual metal pieces are assembled it is usually with a giant welding jig of some kind that holds everything in the proper registration. If the pieces are "unwelded" you may end up with a bunch of wiggly panels unless reinforcements are welded in place before taken apart. Even with NOS parts the original registration of parts may be forever lost.

If possible the best method available is electrolytic rust removal followed by an E-Coat. This is how new cars are done and is state of the art.

Not cheap or original but gives the best rust prevention possible.

If you miss some of it with water,will it still take paint? We have a place in Houston that chemical strips.It is costly, and has its pros and cons.It is said that sometimes it leaches out after painting. Have You ever heard any pros and cons about phosphoric acid??When I took the brackets,and handle from sides of tub,there's rust!! The only rust on the sheet metal(other than seams) is where paint got chipped Or drilled. I'll try the phosphoric acid. Thanks,
Stick

The chemical strippers use an acid bath. The electrolytic process uses electricity in its most basic form.

I would use the phosphoric stripper as this sounds more applicable to the problem especially if the jeep is still assembled.

Contact a pro auto body supplier too as there are all kinds of specialized products available for these problems not seen in regular stores.

It sounds like a commercial chemical stripper or electrolytic process would be overkill to the problem.

Usually power washers are used to wash off chemical stripper especially emphasizing the seams. It might be one of those things that is not perfect in an answer and only time will tell if it has to be fixed again one day.

I hope that helps.

Make sure you use paint stripper first. I use Klean Strip from Home Depot. This takes you down to bare metal or close. You can then sand & wire brush to obtain minimal rust. Then use the Phosphoric Acid. Paint blocks the Phosphoric Acid.

If you can't get to the metal in question with wire brush and sand paper (seams for example) then just spray the Phosphoric on in multiple coats and it should help. I've just found that if the rust coating is too thick the phosphoric acid does not go deep enough to get the underlying rust.

I think there is a point to at which a tub may be past the point of no return and you would have to take it to a professional.

As for the Phosphoric Acid and paint, I don't know the effects of not rinsing as I'm at that stage now and I'll let you know how it goes. I know that I've sprayed Phosphoric over metal & bondo and just wiped it clean and the primer has survived. I probably should have washed it down better but that is not the first mistake I've made and probably not the last.