I would completely cut out the affected areas until you get to solid original metal. That's what I'm going to do on my CJ. Not a big fan of lapping joints on a CJ as both sides of the panels are visible, that and if the seams are not sealed can promote rust between panels. When butt welding the replacement panel do not try to run a continuous bead. Spot weld every 1", then go back and do another spot weld beside the first one working the length of the panel. Continue doing this until the spot welds make a continuous weld.This does take a long time, make sure that the area has cooled before doing the next round of spot welds.

Also don't forget that just because you buy a full panel, you don't have to use the whole thing. I usually just cut patches out of the panel to replace the bad parts as long as the original panel has enough good that you are not replacing 3/4 of it with small patches anyway.

 

If you're plating over the previous rust will continue to grow, and any moisture between the two will start alow for new rust to develop. Read read and read, it just takes time, practice, and patience. Have fun.

 

The CJ5 I have has rust.....didn't know Jeeps Rusted!...

My Jeep came with factory installed rust...

 

my jeep came with factory installed rust...

loooooool

 

Factory installed rust? The "Deeetroit Special Option Package"

 

Cover your windshield while you're welding. I ended with pits in my glass from spatter.

 

I would cut out all the rust. When welding, the cleaner the metal the better. I used several types of connections depending on the situation. I did some butt joints where things needed to be flush such as the exterior and interior. Sometimes they were used in conjunction with a backer strip where I plug welded thru to the backer, then welded the backer on the underside to both pieces. I also did some lap joints with one side flanged so it would sit flush. I wasn't worried about the looks or seeing beads on the underside and all my seams then got coated with POR15 and the seam sealer, then painted again with POR15 and a topcoat. For the visible side it got covered with POR15 then fiberglass reinforced filler to fill any weld voids and to make it smooth and invisible. It's hard to explain it all but see my build thread for lots of pics.
Be sure to do your welding with a series of tacks, spaced apart, and then leap frog over them again starting beside the first round of tacks. Too much heat can warp the thin metal so refrain from doing any "bead" welding. Working on several different areas of the body will allow you to jump around and let things cool while still welding away.

 

I would cut out all the rust. When welding, the cleaner the metal the better. I used several types of connections ...

X2 on that whole post ^^ :thumbsup: 90% of what Renegade wrote here mirrors my experience doing tub repairs to both interior and exterior locations.

Make sure your MIG welder is set up correctly to weld sheet metal. You probably want to go with .023 wire. You must have corrosion-free surfaces before welding. Do not heat up any are too much or else it will warp. The big caution here is that the metal can warp and you may not even notice it until after it's happened. So work slow, take breaks, and let the surfaces cool. Don't rush the work. Make butt joints where you can, but this won't be appropriate for all areas or situations. If you take the tub off the Jeep to repair it, you'll have a much easier time making proper sheetmetal repairs. I would reccomend practicing your welding first on either scrap sheet metal or new sheet metal (I think I paid about $50 for a 4x8 foot sheet of 16 or 18 gauge steel a few years ago). My build thread, as well as other peoples' threads, offer lots of photos and commentary about the sheetmetal repair process.

 

This is a fun read

http://www.fourwheeler.com/how-to/60298/

 

Thanks for the link above....

Thanks!...good info.

 

Since nobody mentioned it yet, if you can afford to, use solid wire in your MIG welder and shielding gas. Much cleaner process for sheet metal work.

You can use flux core wire and weld on sheetmetal, if you have to. I do it all the time, because it's all I have. It's a dirty, labor intensive process of cleaning your spot welds on each go around. Well on the bright side, it gives the metal time to cool so less chance of warpage.

 

Good point, and I believe Ken mentioned using .023 wire, which is only available in solid. Flux core .030 can be a pain to clean up.

 

Yep, Ken mentioned .023. Guys just getting into wire feed welding won't know .023 is solid wire, but you are right, it is.

Flux core wire is a pain to clean up and I'm definitely tired of it. But, it's all I have, so I keep my wire brush close by.

I built a 17 gal fuel tank out of 14 gauge steel sheet metal and welded it together with .035 flux core. People said on the internet, you can't wire feed weld something like that, it'll be full of pinholes. People were kinda right. Soapy water pressure check revealed 3 pinholes. Had to bronze braze em' up. After that never even a hint of a leak.

Took a real poundin' last summer and held together.

Ok I'm done. Topic?

 

Thanks again...

Actually have an old (used) Schumacher welder I got...with a tank. Got it cheap as I was going to do some body work (rusted panel) on an old BMW E30 (RIP...totaled when someone hit me from behind...a week after I got the welder). Even have an old Schumacher stick welder...they don't make either anymore, so I have to figure out how to use the MIG welder on my own...

I've gotten the seats out, and have PB Blaster (can't find my Kroil) soaking on a bunch of the fasteners to get the body off, windshield hinges out, etc....I may try to get pics later this week or weekend.

In looking carefully, it looks like someone did put new panels over the old...the rear area has a rusted out (painted over) panel inside...then a relatively intact panel on top of it (with a bunch of spot welds).

Once I get pics, I'll get advice on how to work around the prior work.

Thanks!

 

Tag for updates.

 

Is it possible to weld with a regular arc welder of a wire welder? or do have to use a MIG?

 

A different oil to try is wintergreen oil it works good on bolts. I used it when I work for the DOD. I've got a question would it be better to use the POR15 on rust or cut it out. I have one spot on the body next to the jeep badge under the door that needs work. Not for sure on how to repair it. If I cut it out the back side brace will have to go
As well as 3 to 4 inches of the floor pan. But either way the floor pan has to go. On the outside I'm looking at about 4" square.
Thanks
Trip maker.

trip maker

 

A different oil to try is wintergreen oil it works good on bolts. I used it when I work for the DOD. I've got a question would it be better to use the POR15 on rust or cut it out. I have one spot on the body next to the jeep badge under the door that needs work. Not for sure on how to repair it. If I cut it out the back side brace will have to go
As well as 3 to 4 inches of the floor pan. But either way the floor pan has to go. On the outside I'm looking at about 4" square.
Thanks
Trip maker.

trip maker

Department of defense?

 

Yes 10 years riding Subs and 5 years working for DOD. What fun yippee. Lol

trip maker

 

I used to own a 1935 ford 5 window coupe back home. I had some metal work done by a professional. I always remember seeing him oxy fusion weld metal, hammer and dolly if and file it. once he had done this there was also no need for body filler.

This summer i am going to learn how to fusion weld.

G>

 

Definitely better to cut it out and replace. Not to say that POR won't buy you some time, but not a better choice. And I like POR so it's not that, it's just that new metal trumps rusted metal every time, painted or not. Now painted new metal is even better yet.

Thanks Renegade I guess I should start cutting out the bad spot and try to figure out how to make new ones to replace them with.

Tripmaker

trip maker

 

To me fusion welding is easy if the position is good and metal is clean. Just get the puddle right and let the two edges run together. I do this at work sealing 16 ga. metal tubes that have been swedged.

 

I'll be keeping an eye on this thread.

I somehow managed to get a floor panel in solid enough to mount my driver's seat to using flux core wire and bubble gum welds.

Had a hell of a time burning through stuff, though.

I'd like to redo it, but am afraid I'll never get it back in... :rofl:
Plus, I know some of the cross members underneath need replacing....

 

Have you tried using a copper backer to limit burn thru? I know it's not always practical to do. And if your not concerned about the appearance of the underside then even a metal backer strip of a thicker gauge that will become permanent may be an option.

 

Good thinking.
Never tried either. But then again, I haven't attempted welding since that debacle... lol

 

Rust

Don't overlap unless you can weld the back side solid. Water, salt, brine and the other crap they put on the road in the winter will just rust jack and eat holes in you repairs so fast your head will spin.:cheers2:

 

Agreed. I usually drill some holes in the top piece (visible side) and plug weld those spots. Then do a fully welded seam on the underside and seam seal. Then the top side (visible) you can cover with fiberglass filler and sand smooth so you can't tell it's a metal seam.

 

Matt, what did you do to that support beam behind where you cut out the square?

Any what size thickness cutting wheel did you use?

 

wm69

I cut just the front face of the support bracket out, leaving both sides attached. Then welded in a new front face. Unfortunately, I didn't take any pics of that step.

Cut off wheel thickness....hmmm...good question. I think it was the thinnest 4.5" disk they had at the hardware store. :dunno:

Matt

 

Matt thanks just what the Dr ordered. I'm off to work be back in three weeks the jump back on it. Need to fine a chunk of copper have to look around and fine some.

Thanks
Tripmaker

trip maker