[dataway]

Let's start with I've been welding for most of my adult life as part of my work in my small fabrication shop. But, I have very limited experience with thin gauge sheet and non at all welding patch panels.

There are some pics below. I've cut up some 22 gauge steel for practice (do most panels use 20 or 22ga?). I'll be starting on the body in a few months so I need to decide what process I am going to use.

I have a couple of basic questions. Are patch panels typically seam welded, meaning the entire seam is welded, or are they spot welded?

How much body filler depth is typically used to cover a patch seam?

TIG butt welds are what I would like to use, but I have the machines here to do anything else required.

Some of the welds in the photos look like they are divots, but it's just they are too shiny and look black in the photos.



Here is an attempt running a gap same thickness as the ga. 75 amps, 1/16" tungsten, silicon bronze filler .... not very happy with it, too much warping.




Here is an attempt using no gap, 75 amps, 1/16 tungsten, no filler. Still to much warping to me, but nothing a body man couldn't massage into shape.



Here is my favorite, no gap, 50 amps, .040 tungsten, no filler, small spot welds. Very little warping but the metal was starting to draw together, a few more spots and it would have started warping.





Is the typical procedure these days to use the spacing clips and just MIG spot weld? Surely people are not sealing the entire seam with weld bead? I want to use the least amount of body filler possible of course. Heck, I'll even give Lead a shot if that is the best way. The application are small patches ( like 4" square at the rear fender lower rear corners, and the lower rear section of front fenders as per typical of Pontiac fenders (so this patch would be larger).

Is body filler ALWAYS used? Does anyone get the welds down so nice that it is not needed?
Thanks

[bkmont]

I'm going through the same process. This fellow says TIG welding thin body panels is the way to go.

https://www.youtube.com/watch?v=WuZYrLzPFwM

[n20ta2]

I but weld the entire seam no spot welds alternating around the panel 8 inches away from the previous spot to keep the heat down to avoid warping. I weld with a gap using a very thin cut off wheel on my due grinder. I fill in the entire panel using a spotlight behind the panel when I'm close to finished to find pin holes I missed. You can drink the welds flat occasionally to help them from building up when stacking. When I welded my quarter on I left additional material on the original quarter and overlapped my new quarter using self tapping screws around the perimeter then I cut the original quarter 8" at a time at the seam mating the two flush and tacking as I went. I had very little warping and great penetration. This works for me.

[n20ta2]

I but weld the entire seam no spot welds alternating around the panel 8 inches away from the previous spot to keep the heat down to avoid warping. I weld with a gap using a very thin cut off wheel on my die grinder. I fill in the entire panel using a spotlight behind the panel when I'm close to finished to find pin holes I missed. You can grind the welds flat occasionally to help them from building up when stacking. When I welded my quarter on I left additional material on the original quarter and overlapped my new quarter using self tapping screws around the perimeter then I cut the original quarter 8" at a time at the seam mating the two flush and tacking as I went. I had very little warping and great penetration. This works for me.

[pfilean]

I do mine with MIG using .023 wire as I don't have TIG. In either case you will need a slight gap. Align the panels and tack about every foot to 18 inches. Come back and tack again between tacks. Then cutting the spacing I half every time make welds about 1/2 to 3/4 long until the seam is finished. Longer welds will tend to close up the seam gap. You may have to grind some at each start and stop when you are finishing up each space to try to minimize the small holes that are left. That may be less of a problem with TIG than with MIG. But when you think you are finished put a light on the inside of the panel and look for the pin holes left at the starts and stops.

Or you could also use a crimper to make a slight offset in one panel and lap the panels. Reduces burn through and has a little more metal in the area for strength. All depends on what you want the finished inside to look like.

[ID67goat]

I thought I read somewhere that with TIG a good general rule was to use 1 amp per thousanths thickness....so around 32 amps for 32 thousandths (22 gauge). Maybe try to turn the heat down? Also I think a lot of guys using 0.023 mig wire for filler wire while tigging panels.

I just bought a TIG recently so I would like to hear what others do on sheet metal. My experience has only been with mig up to this point.

[dataway]

Just did some reading ... most 60's cars and patch panels made for them are 20 ga .. or about .035 .... so would be easier to weld than the 22 ga I was using.

Interesting video, being primarily a TIG welder, I agree. With a .040 tungsten I can make a bead probably 1/16th inch wide, barely visible if making a no gap butt weld. Gets a tad more dicey with a gap. Of course TIG welding on the body itself can be awkward as opposed to bench welding a patch. The front fenders I can do on the bench, the rear wheel opening will have to be done on the body of course.

I'll probably use .023 MIG wire as my TIG filler.

I'll try going down on the amperage even more. I was getting full penetration on the 22 ga at 50amps.

Keep the advice coming, and thank you.

Jeez, ID67, you beat me to it, exactly my thoughts.

[BB70]

I had good luck using a mig and doing spot welds , no continuous welding. I would grind each spot weld where just a bit stood proud and then hammer and dolley each one. Going around to different sections to lock the panel in place. Once the perimeter was tacked I overlap each spot weld to keep pinholes down. The hammer and dolley work kept the gap consistent and warpage to a minimum.

[chiphead]

Let me preface this by saying I'm just another bozo on the hobbyist bus....

I use .023" "easy grind" wire in a MIG with C25 gas. I set my Miller 140 at a little less amps than the weld chart in the door calls for 20-22 gauge steel.

I typically leave a very small gap, as I found that the metal will want to pull together and warp/kink if hard butted before welding. The key is to peen the welds with a hammer on dolly once you lay down a set of tacks. Weld, peen, grind the tops off the welds. Rinse, lather repeat. That stretches the metal back out where it has shrunk in the HAZ. If done properly, it will minimize warping.

This presents a problem if you can't get a dolly on the backside because of space or a brace on the backside of the panel. Sometimes you can get a slapper or something back there to act as a dolly when you peen the weld.

[dhutton]

Originally Posted by dataway

Let's start with I've been welding for most of my adult life as part of my work in my small fabrication shop. But, I have very limited experience with thin gauge sheet and non at all welding patch panels.

There are some pics below. I've cut up some 22 gauge steel for practice (do most panels use 20 or 22ga?). I'll be starting on the body in a few months so I need to decide what process I am going to use.

I have a couple of basic questions. Are patch panels typically seam welded, meaning the entire seam is welded, or are they spot welded?

How much body filler depth is typically used to cover a patch seam?

TIG butt welds are what I would like to use, but I have the machines here to do anything else required.

Some of the welds in the photos look like they are divots, but it's just they are too shiny and look black in the photos.



Here is an attempt running a gap same thickness as the ga. 75 amps, 1/16" tungsten, silicon bronze filler .... not very happy with it, too much warping.




Here is an attempt using no gap, 75 amps, 1/16 tungsten, no filler. Still to much warping to me, but nothing a body man couldn't massage into shape.



Here is my favorite, no gap, 50 amps, .040 tungsten, no filler, small spot welds. Very little warping but the metal was starting to draw together, a few more spots and it would have started warping.





Is the typical procedure these days to use the spacing clips and just MIG spot weld? Surely people are not sealing the entire seam with weld bead? I want to use the least amount of body filler possible of course. Heck, I'll even give Lead a shot if that is the best way. The application are small patches ( like 4" square at the rear fender lower rear corners, and the lower rear section of front fenders as per typical of Pontiac fenders (so this patch would be larger).

Is body filler ALWAYS used? Does anyone get the welds down so nice that it is not needed?
Thanks

You need to planish your welds as you go to stretch the metal back. A little google time will find you a lot of info and videos.

Don

[MUSLCAH]

20 guage

[dataway]

Excellent, thanks folks, hadn't thought of peening the welds. I'll give that a try for sure.

I didn't think this would be very difficult, I use to weld up 24 ga exhaust megaphones without much trouble at all ... I guess that the cylindrical shape makes all the difference.

The two patches where I can't get to the back are luckily small ... maybe 4" square. So hopefully no problems there.

[dhutton]

Planishing MIG welds:

https://www.bangshift.com/forum/foru...hing-mig-welds

Don

[dataway]

Another excellent thread, thanks.

Being that 95% of my welding has been on thicker materials I have not had a lot of experience hammering on welds, actually didn't even know it was a thing, typically if I've had to bring out a hammer it meant I did something wrong

I'm also curious to do some full length continuous welds on butted sheets with the TIG as I can do that with a seam so small you can hardly see it with almost no HAZ ... but I've avoided it with thin sheet because I though the warpage would be unacceptable.

[dhutton]

TIG welds are softer and easier to planish.

Don

[dataway]

Here are my latest attempts. I found some 20-21 ga in the shop ... about .034". Considerably easier than the .025-.026 I was using before.

This is welded with 35 amps, .040 tungsten, butt joint with no gap, no filler.

Started at one end and just made a continuous weld .. about ever 2" I had to stop and planish it a bit, total length about 8 - 9". Probably should have perpendicularly sanded the edges a bit as the shear leaves a tiny bit of distortion there.

After I planished it flat, I put it in the press brake and put some corners on it to imitate somewhat a body panel with curves, angles or some kind of feature that makes the metal stiffer. Then sanded it with 80 grit orbital sander.

A good body man would probably either planish it even flatter and just use high build primer ... or maybe knock the seam down a bit and use filler.

But, TIG welding nice flat pieces on a bench and welding on a curvy, floppy fender might be two different things. Not too worried about the rear wheel opening work ... so many bends in those lower corners that the patch and body will be pretty stiff.

I'm going to have to try SiB rod and a small gap again, last time my filler rod was way too large and I was using too much heat. Theoretically it should be able to be done with SiB with very close to zero warpage.

[ID67goat]

That looks really nice! For the silicon bronze, I have not seen anyone use it for patch panels.
I did see this video where it was used to fill in an area that would have normally been seam sealed.

https://youtu.be/h-yyTcnqVPY

Anyway...looking good...keep us updated with your progress!

[dmorg1]

Johnny,


Whether using MIG/MAG or TIG use the BackStep method on thin gauge. 1-1/2" to 2" or longer segments depending on your abilities and how fast you can travel. Give it a try.


A Keyhole is the only way you can guaranty 100% penetration.



If your TIG machine has a pulser use it, if no pulser on your TIG machine you can pulse with the foot pedal to some extent, it will reduce the heat input.






Dave


http://stellarmachine.com/

[242177P]

Your welds are already amazing compared to mine, but I can offer one piece of advice...



Eastwood has them, pack of four is $24. Or you can get eight of them from Harbor Freight for $7. They're probably Chinese, but two dozen versus four...

https://www.harborfreight.com/butt-w...-pc-60545.html

All I know is that you can never have enough clamps.

[dataway]

dmorg1, have an old syncrowave, so no pulse control. Will try back step ... another thing I didn't think about. Penetration has been good so far borderline too good sometimes, I think I can take the amps down another five. Also, I'm welding with the sheet flat on a 1/2" plate table .... which of course won't be the case with the patches, so I'll have to try some with a good air gap behind it.

I think I'm going to make some of those clamps myself, never looked at them close till now. I have tons of square tube lying around, plenty of wing nuts and hardware. See if I can find some .020" stainless lying around to get the gap as small as possible.
Another good tip thank you.

Good video .... seems I still need some practice. I lean toward SiB because I've had a lot of experience with it and it tends to make mistakes less drastic, weird stuff, sticks to just about anything.