Cab corners

[Matt_50]

I've been patching up the cab lately and I started cleaning up my driver side cab corner today. Both sides need to be done and when I feel inside the inner is rusted too.

I've been trying to find a good walk through for the corners. Something detailed and with good pictures before I start cutting it up. Are the inner and outer welded together? Is there any reason I shouldn't put in corners on the inside to have a flat floor instead of the pockets?

[MARTINSR]

I don't have a walk through for you, but basically you would replace one at a time the inside first then the outside. But it's pretty straight forward, you buy the outside and then the inside you could make pretty easy.

Brian

[Matt_50]

Are the two connected or welded at the bottom?

[8man]

From what I could tell they were spot welded at the bottom.

I cut the outer smaller than the replacement patch to leave me plenty of room to make the replacement outer patch fit. Once the outer was cut away I could see the inner and I just replaced as much as needed to be replaced there. Then I fit the outer, welded up at the cab joint and then spot welded the bottom.

Oh, I left out the weld through primer on all the inside I could get to before welding the outer over the inner.

[Matt_50]

Ok so... I cut out rusted area. Repair the inner. Place new outer patch on outside and trace from inside the cab to outline the cut. Cut it, weld it, spot weld to inner.

[8man]

Pretty much. The time consuming part for me was the fitment of the outer cab corner. I tried to check and double check fitment and lines before I cut too much off of either the cab or the patch.

Also, if you are using less than one cab corner patch panel by cutting it short, you can always cut it out and do it again with another patch panel if you need to.

[e015475]

There's a guy on another board doing some panel repair on an AD. Not much explanation but quite a few photos.........

https://talk.classicparts.com/thread...s.13338/page-6

[b-mac]

Weld slooowly.

You could make the floor flat but there would be nothing to support that can corner. You need the inner.

I have pics of when I did it, but they are on my laptop. Can get to you tomorrow.

[Matt_50]

Great link! I like it when guys post a lot of pics. 8man the more pictures the better. Pictures and YouTube and just trial and error are the only way I learn lol

[e015475]

There's a cracker-jack metal fabricator that's posted a bunch of tutorials on the GarageJournal on welding in patch panels. It isn't specific to cab corners, but he spends a lot of time explaining the finer points of fitting, welding and finishing patch panels.

His name is Robert McCartney (or something close) and calls his shop MP&C. I think he's pretty good at teaching the process. Check him out here-

https://www.garagejournal.com/forum/...d.php?t=182565

[oldman3]

Originally Posted by e015475

His name is Robert McCartney (or something close) and calls his shop MP&C. I think he's pretty good at teaching the process.

e015475, Robert also shows that build on this site, it's it Alternate Tinkings and the thread is this http://67-72chevytrucks.com/vboard/s...d.php?t=564201. Jim

[8man]

Robert really knows his stuff and teaches well. I have read his thread too and really shows a lot. Doing is the way to learn, but reading or watching really helps. If you do it the way Robert shows, it'll turn out.

When welding body panels, I use the ESAB EZ grind in 0.23. Robert suggested that to me. It works better, also he uses a cut off disc to reduce the proud part of the weld. Works well if you take your time and do it slowly as stated above.

[Matt_50]

I like to get a little reading in each day and that link is a great source of info. Next week I hope to order what I need, in the mean time I'm doing other smaller repairs. Driver side lower cowl was a small patch, found an antenna? hole on the driver side below corner window. Ive also got a couple patches to do in the inner cowl area.. well the area between the inner and outer.

I'm a little broke but... I was at Lowe's and I was looking at their small mig welder. What smaller welders would be better for sheet metal than this flux core I'm using now? I'm getting better at it andbim getting less burn through, but man do I have to go slow and still redo spots.

[b-mac]

Get a mig. You'll never regret it. Spend as much as you can.

My Eastwood 175 is nice, and the price was right. But if I had it to do again, I would have spent even more.

Between that and my plasma cutter, I feel like I could build ANYTHING!

Also, I purchased my gas bottle at an Ag supply store. Getting it refilled is inexpensive. I don't use it nearly enough to justify one of those monthly lease programs.

[e015475]

The number of pages in the previous link is something like 139

It's kind of like asking 'what time is it?' and being told how to make a watch.

(I've read it all, and most of it 2-3 times, but that's just me.)

If you want something more to the point try this one-

https://garagejournal.com/forum/showthread.php?t=53534

[b-mac]

Look at Simadre Tech, cheap foreign junk, but mine has been working like a champ for 5 years now.

It's initial test was cutting up the original 49 fame into pieces I could haul to the dump in a small truck bed.

Only downside is I haven't found a competitors consumables that work, but it's cheap enough to buy a few dozen online.

On the Eastwood welder, Lincoln consumables work perfectly.

[OrrieG]

Look at my thread starting with this link. I had to make my inners, they are now repoped. Expect to possibly have to pie cut and massage aftermarket metal. http://67-72chevytrucks.com/vboard/s...2&postcount=47

Later on in the build thread I did the lower door hinge pockets too.

[Matt_50]

Ok guys, my corners should be here Tuesday. I did some more prep and I cut just the rust area out of passenger side. I'm pretty sure I can patch/fix the inner. I can then use it as a reference for driver side.

I may have mentioned I have used a flux core little welder for everything so far. I know it would be ideal to have a better welder and be able to use it... but I don't.

I plan to go extremely slow. I would like some advice on a couple of things.

1st, to help prevent warping. Can I use a heat sink? Magnets maybe? Does that work?

2nd, I'm getting better, but I do get some burn through with this welder. Since this is in a nice hidden little hole and it should be safe from the outside, is it ok to have a strip of metal on the inside across the back of the weld?

[8man]

I have read on Garage Journal a post by MP&C on "how to weld thin metal", specifically what you are trying to weld.

He uses a tack about every 5" +/-. Stops and uses a cutting disc to remove the proud part of the weld. Then when it is smooth like he likes it, he does another tack next to the last over and over until the entire weld line is complete.

Going slow like this will help control heat. Another guy keeps his air hose next to him when doing this. Every once in a while he shoots the weld area with air if he thinks it is getting too warm for his liking.

The area you are welding should be a little more forgiving than say when you replace the bottom of the door and have a long run on a straight piece of sheet. However, you are wise to be concerned about the heat build up and should take precautions.

Where you are welding, you have had a rust through. If you look inside, you may see that there is other metal that has pitted over the years. This pitted metal, when trying to weld may give you a blow out even if all else is set right. I can't speak to what others do, but I slow way down on the blow out, let it cool and start spot welding it in until I fill it back up.

You are right about the gas versus the flux welding. It would be better, but you can do it if you take your time and watch closely. If you think it is getting too warm, cool it down, or stop for a little bit. Patience is your friend when doing this.

If you want to be really cool, check out oxy/acetylene welding. THAT is the way to go, it is at least as good as MIG, some say better.

Now, if you think I'm doing all this, you would be wrong. I am trying. I am getting better at the patience and taking my time and keeping to the spot welds and working each then doing it all again. I can say that when I do, I get much better results.

That's what I think. I'm sure others will have their input as well.

[b-mac]

Yes to your last question. In fact, it might be easier to use a lap weld, rather than a butt, with that flux welder. If you could find a way to create the lap joint. My HF hole punch does a pretty damn good job.
Use the part you cut off as your pattern on the new metal. If your going to do the lap, measure 3/4" more than that. Masking tape will make this gap for you easily.
Lately I've been sheet-metal screwing new metal to old and cutting both at the same time.

You could definitely put a little strip of metal behind there too. That's basically how they do adhesive patches.
If you do that (and maybe if you don't) you might consider some weld through primer on the metal that the welds will trap from paint.

You can use magnets to hold everything, but don't weld directly one them. Heat causes them to lose magnetism.
You can hold copper to the back side of your weld to prevent burn through...and you can't weld to it. Smashed copper pipe will work, but you can melt it.

I welded the first half of my cab with a flux core. It can be done.

[Matt_50]

Thanks guys, ok I think I'll use a strip behind the joint. Spray it with weld through primer too. I'll also try this every so many inches and then make smooth and go again.

Maybe the cutting and making it smooth between each tack will help keep me from over heating. I've noticed if I use cut off wheel vs grinding wheel it's not as hot.

I'll post back after I start to repair the inner.

[e015475]

Overlapped joints is just looking for trouble., Joints should be butt welded. If you don't the repair will telegraph through the paint, and it will certainly rust a lot quicker at the repair

Having a back up strip may not produce the finished product you want. The metal is going to shrink when you weld it. and to get it back to contour you are going to have to planish the weld to stretch the metal back out. This is going to be pretty hard to do with a backup strip in the way

Trim the patch panel first then use a sharp scribe to transfer the joint onto the old truck sheet metal. Cut to the scribe line with a cutoff wheel in a die grinder. Make adjustments with a sanding disk on the die grinder and make the final fit with a file. The more perfect the joint, the less metalwork you'll have to do.

Even if you are very experienced, cutting with tin snips will distort the metal causing it to curl at the edge.

Cutting the two panels together ensures that you are off at least the kerf width of the cutoff blade.

Do a precise scribe off of the patch panel and cut the metal square with a wheel. Grind and file to fit. Sneak up on the fit and take your time. The time it takes to make a near perfect fit, weld it and metal finish it is less than all the metalworking it takes to get a sloppy fitting joint to look ok with metalwork.

If you gas or tig the joint and have proper tacks, you can pretty much weld continuous bead, the weld that is proud of the metal will be easy to grind flush and there will be less work to planish the weld.

[MARTINSR]

Butt weld:

The BEST way to do it.

Overlap weld:

The "bestest" way to do it, if done properly.

The old story on it being a breeding ground for rust, I am sorry, it hit me one day EVERY CAR MADE from the mid thirties, EVERY SINGLE CAR IN THE WORLD is TOTALLY constructed with "lap" welds, The ENTIRE BODY on EVERY CAR!

These trucks, the ENTIRE thing is made of lap welds, what's one more going to hurt?

As long as it's done properly, and sealed properly, it will never be an issue.

There are places where they shouldn't be used, like across a huge panel. But on these corners, it's pretty straight forward.

Brian

[MARTINSR]

Originally Posted by e015475

Overlapped joints is just looking for trouble., Joints should be butt welded. If you don't the repair will telegraph through the paint, and it will certainly rust a lot quicker at the repair

Having a back up strip may not produce the finished product you want. The metal is going to shrink when you weld it. and to get it back to contour you are going to have to planish the weld to stretch the metal back out. This is going to be pretty hard to do with a backup strip in the way

Trim the patch panel first then use a sharp scribe to transfer the joint onto the old truck sheet metal. Cut to the scribe line with a cutoff wheel in a die grinder. Make adjustments with a sanding disk on the die grinder and make the final fit with a file. The more perfect the joint, the less metalwork you'll have to do.

Even if you are very experienced, cutting with tin snips will distort the metal causing it to curl at the edge.

Cutting the two panels together ensures that you are off at least the kerf width of the cutoff blade.

Do a precise scribe off of the patch panel and cut the metal square with a wheel. Grind and file to fit. Sneak up on the fit and take your time. The time it takes to make a near perfect fit, weld it and metal finish it is less than all the metalworking it takes to get a sloppy fitting joint to look ok with metalwork.

If you gas or tig the joint and have proper tacks, you can pretty much weld continuous bead, the weld that is proud of the metal will be easy to grind flush and there will be less work to planish the weld.

And I have to apologize, I am not attacking what you have said, it's all good info. I am just tossing out something here.

On the tin snips, using "offset" tin snips doesn't distort the metal. I use them all the time fitting pieces to butt welding near perfection.

Now I can't emphasize enough, I am not master metal worker who metal finishes something off to perfection without filler. I have, I have the ability to pull it off on easy stuff, I understand it. But I am not that guy, but I do get stuff done like a lot of guys can without those awesome skills. Just keeping it real for the most part, what you have laid out there is all good stuff to make something perfect, I am just laying info out there for the guy who hasn't got all the tools and years of skills to get something done.

Brian

[67GMCkid]

I bought a pair of those eastwood hand fired panel flangers 30 years ago, I found they got more use and are better suited as clamps.. Years ago I bought a Mac Tools air flanger yes it was a bit pricy but sure made things much nicer to work with..


If you flange a panel that gets wet or will hold dust/dirt make sure the lap is pointing down on the backside .
In other words make sure water will run over the joint not puddle into it...

These are what I have

https://www.mactools.com/en-us/Power...nd-Flange-Tool