I just picked up an '83 tub that's in pretty rough shape and will need quite a bit of metal to come back together. It'll need side panels, front floorpans, and the complete rear floor, and braces replaced. The good news is that the tub was free and I have all metal I'll need. The bad news is I have little experience with sheet metal work. Also our camera died so I cant post pics just yet.
My first project will be replacing the rear floor and the three braces. The pieces I have need to be painted but my question is how do I do that and then weld them? When I paint the pieces I'll have to grind down the edges to get a good weld. Is weld thru primer going to be enough protection against rust? I wanted to coat everything in por before I weld but know I wont be able to do that. I know I can go back over the weld with the por but what about the underside of that seam that I wouldn't be able to get to?
You need to clean all the rust off you can get to and then prime them before you weld them together. Epoxy primer is good. You will burn some off around the weld but if you are doing butt welds they should not contaminate the weld.
I like to inject wax into all cavities and if you can get in behind the weld this will protect them.
I would offer this advice since your replacing a majority of the body. Brace, brace, brace! Use braces in multiple places and angles to retain the dimension and shape of the original before you cut away large areas such as the floor. You could tweak things out of alignment by moving the tub, warping with heat, or even just leaning against it. And you might not realize it till you go to marry it with the frame, at which time it becomes a major issue because the work is already done.
I've only ever done one Jeep tub restore, so I'm no expert, but my build thread may help with planning your own plan of attack. As for paint, I did all the welding with bare metal, then etched any rust and painted it with POR. Any place or metal that was to be covered or enclosed I painted first, mostly with Eastwoods Internal Frame paint to seal out air and moisture.
Ok, so I'm going to use the weld thru primer that I bought so that at least the inner parts are all primed. I maybe over thinking this but I was just thinking about the parts that I can't cover with the POR 15 before I weld or after because they will be covered up. An example would be the three braces for the rear floor. I can paint them with the WT primer, but once I weld them on and attach the floor, the inner parts of them won't be accessible to paint them with por. There shouldn't be anyway for water to get into that area, and primer is probably good enough, but I want to make sure I'm doing this right.
Bracing- thanks for that tip, I'm going to pick up some square tubing so that I can do that, especially in the rear since I don't have a tailgate in right now. I'm going to put the tub up on its side to do the welding on the bottom and knew that would affect the body and possibly distort it.
Renegade, I'll check out your build to get some tips. I'm going to do some practicing on this before I start welding the actual pieces. I only have a flux core HF welder and though I'm not building a show jeep, I don't want to be doing more to repair the damage I did while welding.
I painted first, mostly with Eastwoods Internal Frame paint to seal out air and moisture
I had started things using weld thru primer, but even with that it burns away at the weld site and will need recoated along with the weld anyways, so I started using the internal frame paint and then grinding or wire wheeling the paint away where I would weld, such as a plug weld. I'd drill the hole, then mark the hole on the piece under it that I'd be welding to, then I'd grind away the paint in the area of the circle I just marked. Another thing to is, for example the rear bed supports. There may be some holes in it like the factory ones but if not you can drill some. The internal frame paint (and their Rust Encapsulater for that matter) come with an 18" hose that has a conical spray tip at the end. You can feed this into hidden spaces and then spray it as you pull it back out, coating the area inside. There should be alot of examples of what I'm trying to illustrate in my build thread.
No, the internal frame paint can't be welded thru. Any flash rust or re-occuring rust that happened after a few days or even weeks would be taken care of with the etching to be done as part of the POR prep procedure.
For the bracing, square tubing will work fine but angle iron might be cheaper. That's what I used. Tack weld it on in a way that you can easily cut it off later.
Practice with some of the metal you cut out so that you can gauge how easy it is to burn thru. And get some copper to use as backers to help prevent blow thru's because with this thin material you'll get a lot of that. You'll have to use .030 wire because they don't make .023 in flux core.
Great info, thanks Renegade! I didn't think of the angle iron, that will save costs instead of the tubing. I saw harbor freight sells welding spoons and I'm going to pick up one of those up. I haven't gotten the rear supports yet, but from the pic, they don't look like they have the holes in them. I know one of the supports is where the tub is attached to the frame, and I'm assuming the bolts for the seat go into a support also. All parts will be here this week, and if I can get to some welding, I'm going to start working on it friday. I'll check out your build thread for some guidance.
Just find yourself some 3/4" copper pipe and flatten a piece with the hammer. Makes nice backers that you can clamp or use magnets with. For a spoon, shove a piece of dowel rod in part way then flatten the remainder.
Renegade- thanks for the advice on the welding spoon. A piece of scrap copper and dowel is alot cheaper than the prices I've seen.
CSP- I did go through that link and I have alot to learn and alot of practice ahead of me before I start. This isn't going to be a show Jeep, but I want to learn to do this right and I'm really in no hurry to get it done. I'm heading to HF tomorrow for an engine stand since I found a FREE 4.0 motor on CL today, so I'm going to see if they sell those panel clamps. Its driving me nuts waiting on a new battery for my camera as I can't post pics here to get some guidance.
The rear floor and braces came in today, so if I have time tomorrow, I'm going to start working on that area. I also bought a spot weld bit so I can remove the old rear bed. I picked up 40' of angle iron and a sheet of 16g sheet metal yesterday also.
I finally got a camera so I can post some pics. Before anyone says that the tub is too far gone, I need to say that it was free, I have all four side skins and a sheet of 16ga metal, and more time than money. The skins I have are the whole side pieces that go from firewall to rear corners, of 16g(?) galvanized metal that you just apply over the original metal. This jeep isn't going into any shows and I just want to get the damage covered and make sure it doesn't rust through in a few years. The tub has damage all across the rocker panel to the back wheel well on both sides. The PO cut out the damage and welded on some metal to cover the holes.
My plan is to get down to clean metal on the sides and cut out all the rust areas. I'll then use panel adhesive to attach the skins. The instructions I've seen for 3M adhesive is to use it on the front, top, and lower edge, then weld the back edge. I'll do that and also throw some adhesive down the middle of the panels or I'll spot weld them.
So my question on this is, I know that I'll have to get down to bare metal so that the adhesive will work correctly, and also to weld that rear seam. If I sand that paint off and apply the panel adhesive, I'm going to have bare metal underneath the skins. I know it will be covered by that panel, but is there a way to protect those areas of bare metal?
In 1996 I redid the body and went the "skin" route. I don't recommend it but if you are, first cut out ANY rust. Then coat the old metal and coat the backside of the skins. And not with just primer or rust converter. Get some good stuff from Eastwood like their rust encapsulator. Eliminate anyplace moisture can get between the 2 pieces. Seal all the edges with your adhesive.
Thanks for the tips. I understand that the skins aren't the best option, but right now for me they are. A free tub, free skins, a couple tubes of adhesive and a little welding and this thing will be covered up.
I'm going to sand the body down to clean metal and remove all of the rust. I can then go back over it with Prep and Ready and POR. I think I'll keep all of the outer edges, (on the skins and the tub where their edges touch), clean of paint, and apply the adhesive as close to the edge as I can. From the video that I watched, the adhesive acts as a seam sealer. I can then spot weld down the back seam which will keep my welds to a minimum.
I've never welded with galvanized steel. When I spot weld, I'm assuming I need to grind down both sides of the holes? As in the outer and inner skin? And will you eventually get to shiny metal under that gray color to know that you've removed all of the coating and that its safe to weld on it?
Are these skins you got galvanized? I don't think I've ever seen them come that way. But if they are be cautious when welding as it gives off a toxic fume. I've never welded any so I can't give any advice there, but for the other sheetmetal, yes, grind it to clean metal before welding. Don't grind too hard, it's thin to begin with.