While discussing this subject on another forum I couldn't stop typing and ended up with a "Basics".
“Basics of Basics” Butt welding panels
By Brian Martin
Butt welds are literally making two parts ONE, whereas a flange is “sort of” making it one. Let me put it this way, a highly skilled metal man can but weld two pieces together metal finishing both sides and you couldn’t tell it’s been welded on the front OR the back! It is truly making it ONE piece.
The flange welded seam is as the factory would do in most cases, it’s done on a rear roof pillar of most GM cars in the sixties for instance, then covered with lead. But done the middle of a panel is asking for trouble. It will likely show because you have made that area stronger. The metal around it moves a little through bumps or whatever and that area doesn’t, thus you end up with “ghost lines”. At least that is how I see it, I could be wrong. Or it’s a combination of a few factors.
However flange type welds are a good way to go depending on the location, your expectations of the job, the time you have, and your skills.
One thing I do have to say the added flange as a point for rust is something you don’t have to think about in my opinion. The car or truck, every single one of them made in the last 100 years are entirely held together with a “lap” weld of some sort, pinch, flange, something. Think about it, what is one more in the body that has 50 of them?
That all being said, the flange or butt weld with backing which was once the “industry standard” in collision repair is fading away as the norm. A number of car companies have changed and now do not recommend it and want you to butt weld everything non-structural, and some structural too.
So after years of using this industry standard I went to a Toyota school for repairs on their cars and was blown away seeing they wanted us to butt weld a 22 gauge quarter! HUH? Are you kidding me! I came back from that class and started doing it right away, it was no big deal and I was blown away at how easy it was, once I was forced to and just frigging did it instead of saying it couldn’t be done. This is with a MIG welder.
Now as far as a gap at the butt that people will often recommend that I have found to be wrong. I think it comes from the welding class at school where they taught to bevel the edge on thicker metal to get the correct penetration or something, I am not sure but no gap is better than a gap. I first got a whiff of this when I picked up a little book on butt welding from Ron Covell a leading metal master in the industry. Ron Covell Creative Metalworking Workshops In this book (which was actually written by someone else) he did a little test where he welded a few butt welds with no gap, then with varying gaps and measure with a micrometer how much it shrank, and yes, the larger the gap the more it shrank! The shrinking causes the warping you get when you weld sheetmetal. It’s not the heat that causes warp, it’s the cooling after it’s heated, where it shrinks back, only it shrinks more than before it was heated!
So after not using a torch to weld for about 30 years I have found myself reliving my first years doing this work and loving it. I put on my old albums from my childhood on a record player out in the garage and work on my truck to Santa and Steppenwolf.
This came about due to a new co-worker of mine. He came to the shop after working at a restoration/hotrod shop and is a hell of a fabricator. When I told him what I was chopping the top on my truck he said “Please don’t tell me you are going to use a MIG on that”. I sheepishly said “I was planning on it.” He responded that he didn’t have anything to talk about then and walked away. LOL Come on I said asking him what he is talking about. He said I must TIG or gas weld it if I want to do it right. So I started talking to him about the subject of welding and warping and learned a LOT.
He told me stuff that frankly sounded like he was out of his mind, come on, it was like he never welded in his life and he was making it up. That is how crazy some of what he said was to me, it was one of those “You don’t know what you don’t know” facts. Right off the bat he said that you want no gap, ok, I got that, and you will weld it without any filler rod! Oh come on! When I told him I had a Jewelers torch that is all he had to hear, yep, I would be welding it (at least some of it) without any filler rod. Where I did use some, it would be .023 MIG wire.
Jewelers torch link Propane & Mapp Torch Kits | MSCDirect.com
Ok, so I would be welding without rod, that was the first shocker, the next one made that look like nothing. The next tip he had for me would flip me on my head. This would be to weld in one continuous weld without stopping! Yep, weld the seam across the roof without stopping! Now this went against everything I had ever understood about welding sheetmetal. From when I chopped my first top on the my truck in 1974 I was taught by the old timers in a Rod & Custom magazine to lay a short weld, then planish it with a hammer and dolly until cool, then weld another short bead and do the same until the whole thing is welded. Skipping around was recommended, so that you don’t heat it too much in one area. This is what I learned years ago and watched every bodyman I worked with doing it the same way.
But after he explained it a few dozen times, in four different languages, with pencil illustrations, I was starting to believe him. It started to make sense, you keep the HAZ (Heat Affected Zone) uniform allowing for the metal to cool evenly, and thus not causing warpage! I get it, I get it!
I started looking at it like this and started practicing the method of welding with my gas torch using zero gap in the panel, fusion welding without any rod and weld it with one continuous bead. And I am blown away that this works amazing well. Below is an example of tacking a part in using this method.
Another interesting tip he game me was to not worry about getting it perfectly clamped in all flush like it’s finished. As long as it CAN fit, that you have to make sure. But when you weld it, you only need it perfect in literally one spot, you tack it, then align another spot where it is perfectly flush, and tack it, then align another spot, then tack it. Once it’s all tacked you planish it flat and you are ready to weld the whole thing…….in one bead! I use to set it up so perfect and this is a total waste of time using this method, I can’t tell you how shocked I was when I started doing this, it was like I was bending metal with my mind!
No filler rod welding, click on the photo or the link below it.
http://vid200.photobucket.com/albums/aa167/BasicsofBasics/My Truck/DSCF5189_zpse1a180bf.mp4
Here is my first example of welding without stopping, no filler rod except on a few holes where I blew through tacking it. Check out the HAZ and how uniform it is. Doing it the old way welding here and there and skipping around and planishing each weld that HAZ would like links of a chain. This area was down about an eighth inch in the middle, I planished the welds and brought it right up.
I find myself sitting here typing this and I haven’t worked on my truck practicing this in many months due to some other projects I had to do around my home. So more and more things keep popping into my head, this is a biggie. When I welded in the past and ended up with warpage away from the weld I would go out there and start working that big low spot. WTH? Why in the living hell would you work out there, what CAUSED IT to warp out there didn’t happen out there! It’s not like you hit it with a hammer out in the middle of the roof for goodness sakes. So why would we work out there? What caused it is the weld, so that is what you need to work, usually you just need to planish it thinning out that metal that has “gathered” as it cools (which is exactly what is happening) to correct the warped low spot out away from the weld.
Anyway, I can’t stress enough, I am NOT a “tinman” metal master so things I have said are simply what I have learned to work and I am open to any suggestions. After learning what I have learned from my co-worker after all the years I have done this stuff, you darn tootin I want to hear any tips you have.
And the suggestions given are for working with a gas or TIG welder not so much MIG. The MIG welds are so hard that planishing them is unrealistic. You can grind them down carefully and then planish, but again, the weld is SOOOOO hard that you just can’t do it like with the gas or TIG. You can butt weld smaller areas like a rocker or something MIG welding, where you won’t need to planish it though.
“Basics of Basics” Butt welding panels
By Brian Martin
Butt welds are literally making two parts ONE, whereas a flange is “sort of” making it one. Let me put it this way, a highly skilled metal man can but weld two pieces together metal finishing both sides and you couldn’t tell it’s been welded on the front OR the back! It is truly making it ONE piece.
The flange welded seam is as the factory would do in most cases, it’s done on a rear roof pillar of most GM cars in the sixties for instance, then covered with lead. But done the middle of a panel is asking for trouble. It will likely show because you have made that area stronger. The metal around it moves a little through bumps or whatever and that area doesn’t, thus you end up with “ghost lines”. At least that is how I see it, I could be wrong. Or it’s a combination of a few factors.
However flange type welds are a good way to go depending on the location, your expectations of the job, the time you have, and your skills.
One thing I do have to say the added flange as a point for rust is something you don’t have to think about in my opinion. The car or truck, every single one of them made in the last 100 years are entirely held together with a “lap” weld of some sort, pinch, flange, something. Think about it, what is one more in the body that has 50 of them?
That all being said, the flange or butt weld with backing which was once the “industry standard” in collision repair is fading away as the norm. A number of car companies have changed and now do not recommend it and want you to butt weld everything non-structural, and some structural too.
So after years of using this industry standard I went to a Toyota school for repairs on their cars and was blown away seeing they wanted us to butt weld a 22 gauge quarter! HUH? Are you kidding me! I came back from that class and started doing it right away, it was no big deal and I was blown away at how easy it was, once I was forced to and just frigging did it instead of saying it couldn’t be done. This is with a MIG welder.
Now as far as a gap at the butt that people will often recommend that I have found to be wrong. I think it comes from the welding class at school where they taught to bevel the edge on thicker metal to get the correct penetration or something, I am not sure but no gap is better than a gap. I first got a whiff of this when I picked up a little book on butt welding from Ron Covell a leading metal master in the industry. Ron Covell Creative Metalworking Workshops In this book (which was actually written by someone else) he did a little test where he welded a few butt welds with no gap, then with varying gaps and measure with a micrometer how much it shrank, and yes, the larger the gap the more it shrank! The shrinking causes the warping you get when you weld sheetmetal. It’s not the heat that causes warp, it’s the cooling after it’s heated, where it shrinks back, only it shrinks more than before it was heated!
So after not using a torch to weld for about 30 years I have found myself reliving my first years doing this work and loving it. I put on my old albums from my childhood on a record player out in the garage and work on my truck to Santa and Steppenwolf.
This came about due to a new co-worker of mine. He came to the shop after working at a restoration/hotrod shop and is a hell of a fabricator. When I told him what I was chopping the top on my truck he said “Please don’t tell me you are going to use a MIG on that”. I sheepishly said “I was planning on it.” He responded that he didn’t have anything to talk about then and walked away. LOL Come on I said asking him what he is talking about. He said I must TIG or gas weld it if I want to do it right. So I started talking to him about the subject of welding and warping and learned a LOT.
He told me stuff that frankly sounded like he was out of his mind, come on, it was like he never welded in his life and he was making it up. That is how crazy some of what he said was to me, it was one of those “You don’t know what you don’t know” facts. Right off the bat he said that you want no gap, ok, I got that, and you will weld it without any filler rod! Oh come on! When I told him I had a Jewelers torch that is all he had to hear, yep, I would be welding it (at least some of it) without any filler rod. Where I did use some, it would be .023 MIG wire.
Jewelers torch link Propane & Mapp Torch Kits | MSCDirect.com
Ok, so I would be welding without rod, that was the first shocker, the next one made that look like nothing. The next tip he had for me would flip me on my head. This would be to weld in one continuous weld without stopping! Yep, weld the seam across the roof without stopping! Now this went against everything I had ever understood about welding sheetmetal. From when I chopped my first top on the my truck in 1974 I was taught by the old timers in a Rod & Custom magazine to lay a short weld, then planish it with a hammer and dolly until cool, then weld another short bead and do the same until the whole thing is welded. Skipping around was recommended, so that you don’t heat it too much in one area. This is what I learned years ago and watched every bodyman I worked with doing it the same way.
But after he explained it a few dozen times, in four different languages, with pencil illustrations, I was starting to believe him. It started to make sense, you keep the HAZ (Heat Affected Zone) uniform allowing for the metal to cool evenly, and thus not causing warpage! I get it, I get it!
I started looking at it like this and started practicing the method of welding with my gas torch using zero gap in the panel, fusion welding without any rod and weld it with one continuous bead. And I am blown away that this works amazing well. Below is an example of tacking a part in using this method.
Another interesting tip he game me was to not worry about getting it perfectly clamped in all flush like it’s finished. As long as it CAN fit, that you have to make sure. But when you weld it, you only need it perfect in literally one spot, you tack it, then align another spot where it is perfectly flush, and tack it, then align another spot, then tack it. Once it’s all tacked you planish it flat and you are ready to weld the whole thing…….in one bead! I use to set it up so perfect and this is a total waste of time using this method, I can’t tell you how shocked I was when I started doing this, it was like I was bending metal with my mind!
No filler rod welding, click on the photo or the link below it.
http://vid200.photobucket.com/albums/aa167/BasicsofBasics/My Truck/DSCF5189_zpse1a180bf.mp4
Here is my first example of welding without stopping, no filler rod except on a few holes where I blew through tacking it. Check out the HAZ and how uniform it is. Doing it the old way welding here and there and skipping around and planishing each weld that HAZ would like links of a chain. This area was down about an eighth inch in the middle, I planished the welds and brought it right up.
I find myself sitting here typing this and I haven’t worked on my truck practicing this in many months due to some other projects I had to do around my home. So more and more things keep popping into my head, this is a biggie. When I welded in the past and ended up with warpage away from the weld I would go out there and start working that big low spot. WTH? Why in the living hell would you work out there, what CAUSED IT to warp out there didn’t happen out there! It’s not like you hit it with a hammer out in the middle of the roof for goodness sakes. So why would we work out there? What caused it is the weld, so that is what you need to work, usually you just need to planish it thinning out that metal that has “gathered” as it cools (which is exactly what is happening) to correct the warped low spot out away from the weld.
Anyway, I can’t stress enough, I am NOT a “tinman” metal master so things I have said are simply what I have learned to work and I am open to any suggestions. After learning what I have learned from my co-worker after all the years I have done this stuff, you darn tootin I want to hear any tips you have.
And the suggestions given are for working with a gas or TIG welder not so much MIG. The MIG welds are so hard that planishing them is unrealistic. You can grind them down carefully and then planish, but again, the weld is SOOOOO hard that you just can’t do it like with the gas or TIG. You can butt weld smaller areas like a rocker or something MIG welding, where you won’t need to planish it though.