Welding my tractor hood

[Tinhack]

I've butt-welded a lot of sheet metal in my time. The trick is to skip around and have a hammer and dolly to work the welds. Skip back and forth from the inside of a weld line out. Don't weld the ends first--Not even tacks or you'll trap the expansion and warp the panel. If the panel was large, I used a wet rag to cool down a weld before moving to the next. Welds shrink. Some hammer and dolly work will stretch it back out. Don't be in a hurry.

The pictures below show the hood on the Kenbota as stock and after I added about 13-14" to it (I forget exactly). Absolutely no, none, zero, zip, zilch body filler was used. It's all metal work.

Original auction photo.

During the build.

 

[5030]

I am familiar with stick and have quite a bit of experience with resistance.
I’m only proficient in mig but the intricacies of the welder never mattered to me, I wasn’t paid to do perfect work, I was paid to do a job that oftentimes the manufacturer themselves did very poorly on.
It sounds like I would need a tig welder ( again) and quite a bit of experience to do a standup job so once again I will just do my best with what I have.
There are many things I’d like to make a career out of, welding is one of them and I wish that I had nine lives to do them all.
Thanks for your informative post

In reality, if you can gas weld and/or braze, you can Tig weld as well. Onky difference is, when TIG welding, you must keep the filler rod in the gas envelope, at all times and most if not all of the latest TIG welders have built in programs that make setup super easy, they are almost to the point where they can weld for you... And remember, a TIG welder will also run in SMAW mode as well with low hydrogen electrodes so you get a multi purpose machine, in fact, most TIG welders come with a stinger for welding rod.

 

[TractorGunn]

At this point I don’t believe that your friend doesn’t have warpage issues, maybe he knows something I don’t though

Dial the welder down and deal with a poor weak weld, turn it up and deal with it warping.
This has been my experience
Of course I’m sure that some really proficient welders could really dissect the welder and material I am using to weld with but I have no experience with this.
I’ve always used the rolls of mig wire I was handed.
Thanks

It would be a slow process to tack this intermittently and cool it down in between with cold rags and/or time until it is completely welded.

Having been a welder and limo builder in the past, it can be done without warpage, you just need to know your heat and metal, and take it slow. Minimum filler would be needed if done correctly.

 

[1930]

I've butt-welded a lot of sheet metal in my time. The trick is to skip around and have a hammer and dolly to work the welds. Skip back and forth from the inside of a weld line out. Don't weld the ends first--Not even tacks or you'll trap the expansion and warp the panel. If the panel was large, I used a wet rag to cool down a weld before moving to the next. Welds shrink. Some hammer and dolly work will stretch it back out. Don't be in a hurry.

The pictures below show the hood on the Kenbota as stock and after I added about 13-14" to it (I forget exactly). Absolutely no, none, zero, zip, zilch body filler was used. It's all metal work.

Original auction photo.
View attachment 3495838

During the build.
View attachment 3495839

Looks good, I will try this when I get to that point

 

[sandman2234]

Every time TIG welding comes up in a discussion, I think of what a welding class instructor told me. I had drawn one of the "tig booths" as an assignment and went after it like I was on a mission. I got pretty good at it, and got itchy to want to try out one of those new-fangled "MIG Guns"! I carried my latest example of my TIG work over to the instructor (real nice job of welding, I might add) and asked if that was good. He complimented my work, so I asked him if he thought I could take a run at one of those MIG guns. He laid a hand on my shoulder, leaned in and whispered in my ear... "I can teach a monkey to run a MIG gun, so get your tail back into that TIG booth, that is where the money is at"! To this day, you can count one one hand the number of times I have had a MIG gun in my hands.
TIG is great, MIG is faster, and an old Lincoln Tombstone gets used around here more than anything!
David from jax

 

[AntiqueIron]

Preface: I am a horrible welder. Full stop, bird poo esque boogers is how I do repairs.

Based on what I see, I'd be tempted to cut all the way back behind the louvers, and do all that as a replacement. That cut is so close to the louvers it's gonna be a helluva time trying to weld, sand, fill, etc. in there.

I've heard of guys clamping copper bars behind the butt weld on sheet metal; it absorbs the excess heat and helps keep the steel cool.

I would say a *thin* coat of body filler isn't anything to be afraid of- skim coatings of good quality material won't be an issue. They make heat resistant versions, flexible versions, whatever you want.

But... this is coming from somebody who is nowhere near a pro at this stuff.

 

[Tinhack]

I've heard of guys clamping copper bars behind the butt weld on sheet metal; it absorbs the excess heat and helps keep the steel cool.

Yep, except I use copper sheet about 2mm thick. Somebody spilled the secret beans.

 

[TORQUIN]

Mig tacks with an unlike metal backing will get the job done. I'd put copper or aluminum, minimum 1/8" thick, behind the sheet metal to help with blow-through. If it is clamped tightly to the weld material it will help with heat dissipation also. Practice on similar sheet metal first, like your beat-up hood. The tacks will need to be spaced out far from each other so as to minimize the heat you put into the metal. You can cool with a wet rag or something else as you go, but patience to let it air cool works too. It would be better to have a step in the sheet metal and overlap the pieces a little, if that is possible. A lap weld will provide more heat dissipation than a butt weld.

Chris

 

[AndrewT]

you don't need a backing bar, and you don't need a TIG, unless you want a reason to sell the other half on buying one lol.
Go on Youtube, search up Make It Custom, and watch a video called Mig welding with no warpage . Been doing Auto restoration for 40 years, started out doing patches like that with a double nought Oxy-Acetalene tipped torch,fusion welded with the tiniest bit of filler rod, and moved to a Mig for speed later on in life. Having a patch piece from another hood will help, but it looks like it's fairly flat , unless there is a dimple/relief behind the air cleaner..

3 things are most important. Fit must be perfect, spend time there and it will save you double finishing the patch later. It insures the movement warpage is as uniform as possible all the way around the patch.
Control the heat, Carl's trick of using the air nozzle works a treat, I usually just use patience. I've welded in 62 Impala rear quarter lowers in one pass, but the panels were fit so well light wouldn't pass the gap once fitted, and they were tacked every 1/2 inch, and the tacks ground flush prior to the last weld, to stop the panels from reacting differently where the tacks were located ( thicker shrinks up for a given heat as the weld sits on top lifting the weld up).
Practice on some butt joints, get your welder set so the weld penetrates the same amount on the backside and the top, the metal will shrink ever so slightly but not warp up or down, and use a series of tacks to form the bead. Doing a continuous weld sans warping is possible but even I don't do that anymore, as it isn't an everyday task these days, and I'd practice a bit before doing the weld that counts .

Anyways watching the Video will show you the quick and easy way, more easily than I can explain it to you.

 

[CoyPatton]

Absolutely but it needs to be welded solid however at some point.

Sounds like you have plenty of experience to do the job. I would guess as much and probably more experience than me. But that has seldom stopped me from expressing my opinion (like armpits, we all have them, they often stink).
As you know is an enemy anytime you weld. It is a larger enemy with thinner metal as you also know.
1) low heat setting on welder
2) small weld lengths (stitches) and move quick along the piece
3) weld as far from last weld as the piece allows
4) walk away and do something else
to let the piece cool down.
5) grind it smooth.
6) tractors vibrate a lot, in my experience filler easily cracks, consider using JB Weld or some type of epoxy as the filler.
7) do the prep work with sand paper and the paint starting with good primer. May need more filler and sanding after primer dries.
Good luck.