Welding Floor pans

[AmJay]

A friend of mine will loan me his MIG welder. It's a cheap 110v 45/90 Amp flux welder. It's set up for 30 guage. He says it can take 35 gauge wire if I buy the tips and wire. Does anyone know if this would be good enough to weld in new floor pans? My guess is it will make a lot of holes and probably warp on the 20 gauge steel I was going to use. I'm not sure the floor pans are even 20 guage. Has anyone done this? Do you think it would work? I really should buy my own MIG one of these days.

 

Mac...

[terrawombat]

I think you mean it currently has .030" wire and you'd like to put 0.035" wire in it. If you're only putting 20 gauge steel sheet in the floorpans, then that welder is probably fine the way it is currently setup. 20 gauge sheet is pretty thin stuff - I think the original floorpans were at least 18 ga., but I may be wrong...I'm just going off what my YJ Wrangler tub was made from and the MJ could be different. I used 14 ga. steel to repair my MJ floors. It was definitely thicker than stock, but I didn't want to mess around with replacing those again as it's not the most enjoyable job in the world. I used a 110v Lincoln MIG welder - the kind you get from Home Depot, but mine is setup for CO2/Argon gas and I use 0.023" solid wire.

[Eagle]

For welding in floor pans you won't have warping because must of the welds are spot/plug welds in the "field" of the piece, where it lies on the frame rail and gets tacked to the flanges thereof. Where the edge of the pan is welded to the side sill, juts stitch weld it ... don't run a continuous bead, do a weld maybe an inch long, then move to another area and do another 1" weld. Eventually you can come back and fill in the gaps between the stitches until you have a continuous weld.

[Wildman]

:agree:

 

Welding wire is labeled as "Thousands of an inch" not gauge.

 

But.......your better going with .023 flex-core wire for sheet metal with a 110v welder.

 

.035 wire is generally used for steel 3/16" -1/4"+

 

Plus, you need to watch the "Duty-rating" on the welder, .035 pushes the duty rating down.

 

.023 is easier on the duty rating.

 

Duty rating = amount of time you can weld between cool down cycles.

 

I prefer solid wire with gas, that way you can increase the gas pressure if your starting to burn thru sheet metal. And you get a cleaner weld, less splatter and scale with using gas.

 

But, you have to deal with what your friend is loaning you ;)

 

The 20 gauge sheet metal your using should be fine for the floor pan, a little thin, but easier to work with for shaping it it.

[terrawombat]

When I did the floor in my MJ, I tacked the replacement panel down on one corner using a very small bead (maybe 1/8" or a little larger). I then worked around the rest of the pan molding it to the original MJ floor and continued to use small tacks about 1.5" apart. After it was tacked up and to my liking, I went back over each tack and put down about a 1" long bead, but there were still gaps in between. I used a high quality seam sealer (The brand name is escaping me right now) and it has held up very well so far. I was very liberal in the amount of seam sealer I used and I applied it both on top and on the bottom of the new replacement panel. I used POR-15 on the bottom of the panel (underneath the truck) and Valspar Tractor & Implement paint on top (inside of the cab). Would have used POR-15 on both sides if I had enough of it. That stuff is too expensive for me to keep a large supply of it.

[AmJay]

Thanks guys. He dropped the welder off, but I have lawn chores so won't get to it for a few days. I thought the wire was gauge like electrical wire. Thanks for clearing that up. The welder came from Harbor freight and just has wire speed and high low setting. I don't know the duty cycle but I'll assume it's very low. He was mistaken it has .035 wire. The pinch wheel has grooves for 2 sizes. So, I'll get some .030 wire and tips and do some practicing. I don't think I'll go any thicker then 18 gauge steel probably 20 because I have to be able to bend it and cut it and 16 is just too hard for me to work with. I don't think the floor pans are that thick. I think they use a higher carbon steel then my thicker CJ floor pans. I plan on replacing the carpeting with vinyl so moisture won't be as big a problem as carpeting. I'll also paint on some POR 15. My floor pans rusted from the inside out. My Comanche was Zebarted by someone years ago as evidenced by the plugs in the rocker panels. I wonder how flammable that stuff is? Anyway, this is probably a good place to start learning how to weld since It'll all be covered and looks aren't that important and if I like it I can buy a welder with the money I'm saving having a body shop do it.

 

Mac...

[ejndssn]

just post some pix as you go along this route :cheers: for the rest of us that would like to do this as well :brows:

[green_miner]

i know this isn't the "right" way to do it but in my dad's 88 we used an old mj hood that we had for the sheet metal for the floor. worked pretty good. we had to make 3 sections and weld them together as we went along. i'll see if i can get some pics in the next couple days

[terrawombat]

I'll toss some pictures up. I didn't get any once I applied seam sealer (and I already reinstalled the interior), but here is what I've got.

 

Rust:

 

Cut out the bad:

 

Weld in the good:

 

Fit the good:

 

Good welded in:

[Eagle]

My amigo Jeepero Erich, down the road, is replacing the driver's side floor pan in his MJ even as we speak. We spent three days drilling out spot welds and cutting an intact floor pan out of one of my XJ hulks so he could weld it into the MJ. He has removed the entire floor from part way up the tranny tunnel clear across to the door sill.

 

I asked about photos and he said he is taking them as he moves along, so once he's finished he has promised to post a write-up.

[AmJay]

Nice Job Wombat. I hope mine is no more rusted then yours. Right now I slipped some old license plates up there so I don't look like Fred Flintsone. What guage are the old floorpans and what gauge are the patches? Did you just stitch weld or did you come back and weld the whole thing? What kind of seam sealer did you use?

 

Green_Miner I thought about using an old hood or body panels off my wreaked Comanche too.

 

I'll get some pictures once I star. I need a critique on my welding and I like embarassing myself. I switched to .030 wire and did some practicing on really thin 22 gauge. I didn't burn any holes. I did have too much penetration. I'll be using thicker steel on the floor pans. The low setting on this welder is actually 60 amps according to the manual, I think lower amperage would have worked better.

[Wildman]

You could always check out this site for some welding tips on body work, lots of info there to weed thru -

 

http://autobodystore.com/

 

The real secret with mig/core welding is getting the buzz.

 

And, Not this :chillin: buzz........... :shake:

 

When your welding and you got the right amp setting, right speed, and right angle, you'll hear the weld buzz. That when you got a good weld, with good penetration.

[AmJay]

Well I finally got around to starting my floor pan repairs. Here are some pictures of what I'm starting with.

 

 

 

 

I was a little surprised that the passenger side is rusted at the back behind the seat. It is rusted through on either side of the frame rail. Well time for some grinding.

 

Does anyone have a secret to get out those t50 Torx bolts that hold the seat belt? I've ruined a USA made torque wrench T50 and they didn't budge. I got 3 of them out and 3 still stuck. I can't use heat because the belt is still attached.

 

Mac...

[Cheech]

 

Does anyone have a secret to get out those t50 Torx bolts that hold the seat belt? I've ruined a USA made torque wrench T50 and they didn't budge. I got 3 of them out and 3 still stuck. I can't use heat because the belt is still attached.

 

Mac...

 

When I removed the top seatbelt bolts I used a set of vice grips. Even then it was pretty tough, I really had to clamp them down tight.

[jimoshel]

I crawled under neath and wire brushed the threads as best I could. Soaked them with penetrating oil and let set overnight, then used an impact wrench set at a medium setting. You want to vibrate them out. Not twist the head of.

[kastein]

Seat belt bolts - not sure if this is different on the MJ (haven't had to do mine yet) but on the XJ, they are tough to get out because they stick through the bottom of the floor and get covered in gunk and rust. So hit the exposed threads with a wire wheel before you start turning them, then apply a bit of your favorite penetrating oil and your personal assortment of 4-letter words and they should move easier.

[AmJay]

I started replacing my floor pans at the end of May and just finished them yesterday. Here are some shots. Keep in mind this is the first time I ever welded and I realize the welds aren't very good. I burned a lot of holes, forgot to turn on the gas once and had a hard time at all the weird angles I had to weld at. Still, I'm pretty confident the welds will hold up and since everything is covered, looks aren't too important. here's some pics.

 

This is the passenger side front and rear. I don't know why, but I didn't take any of the drivers side until after I seam sealed and painted it.

 

 

 

 

I bought replacement floor pans for the front driver's side because they were completely gone. I must have ordered the rear floor pans by mistake because that's what they sent me. I reordered them and got the right one. I decided to keep the wrong ones and used the metal to patch the passenger side and the rear driver's side.

[AmJay]

I painted everything with etching primer and then some spray on truck bed paint. The underside received the same treatment with seam sealer. The seam sealer came in a caulking tube and went on great.

 

 

 

 

 

In the next picture you can see the brace that runs from the front to the back was completely gone. After a lot of hammering I was able to form the floor pan over the rusted off stub. I spot welded the floor pan to the top of the frame. It doesn't show up too good in the picture because I ground off most of the weld. It's welded about every inch.

 

 

While cutting out the rusted floor I managed to cut through the e-brake cable. I was pretty rusted too, so it was a good time to replace it.

[AmJay]

Now the fun part, putting it all back together... I decided to try vinyl flooring. It's formed for the Comanche. It's very thick (About an 1/8") and very heavy. It's long on both sides and the back and doesn't have any holes cut out for the shifter, seat bolts, etc...

 

 

 

 

 

The center console has gaps between the flooring and the console. I think if I apply heat I can get some of the wrinkles out of the vinyl if it acts like shrink wrap tubing, otherwise I'll just live with it.

 

When I started this I said if I liked welding I would buy a welder with the money I saved by not taking this to a body shop. I imagine I have about 20 or 30 hours in this and that would probably be a couple thousand at a body shop. The friend I borrowed the welder from needed it back and so I bought the welder before I started. I looked at Lincoln, Miller, Hobart and ended up getting an HTP 130. I added gas and did all the welding with .024 wire. It's a nice welder in the hands of a crappy weldor.

 

 

I'm scrathing this one off my Comanche todo list.

[AmJay]

I know I got it sealed good because when it rains, the floorpan holds all the water that comes through the firewall!

 

LOL.

 

I'm hoping mine will hold all the water coming through the sun roof, but incase it doesn't the vinyl floor will.

[comenschen]

Where did you get the vinyl flooring from? Still wondering what I want to do with mine after I finish patching the floor. I figured I would bedliner it and just use some big heavy rubber floor mats. That way it can dry out if I happen to take the truck for a swim :D . I would think water would get trapped under the vinyl?

[AmJay]

I bought the flooring here.

 

 

I suppose water could get trapped under the flooring. The only holes on the bottom are where the seat bolts come up through the flooring and that's pretty much sealed by the seats being bolted down. I have bed liner on my CJ7 it works pretty good. Anything is probably better then carpeting on the floor. My main concern is getting in with my snow, slush and salt covered boots in the winter. That's what I think ruined the floors in the first place.

[comenschen]

Thanks for the link!

 

I may end up doing the vinyl floor. I certainly don't want carpet for the same reason as you....my truck will see alot of winter and slushy boots. My concern was offroading and going through really deep water. Realistically though, I doubt that would happen much if at all. If so, pulling out the vinyl after such a trip wouldn't be too much work, and would only happen once a year tops.