Who acetylene welds their body splice panels?

I'm getting kinda frustrated with the brittle welds when I splice panels with a wirefeed. Anyone here use a gas welder? Any tips I should know before I go at it and warp the crap out of everything? Got any photos of your work?

 

search for "hammer weld", theres some great tips in some old posts

 

I shortened my street baja 14 1/2" - frame & all - using nothing but a torch for welding. Didn't have a mig at that time. Biggest thing is to weld about an inch, & cool it down with a wet rag. Takes a long time. Pics of "Lady Blue" (current working name at http://angelonearth.net/me.html. Sorry I don't have the pics of the build handy - not even sure where they are...
BTW the page/site needs updating *bad*. I no longer even have the Cabriolet (& I really miss it).
~ Paul
aka "Tha Driver"

I don't take shit; I don't give a shit. I'm not in the shit business.

 

Back in the "OLD DAYS" thats all they had to the welding on early customs etc. the trick is to use small wire and a small 0 or 1 tip, and do a little at time. The P-51 in Ryans post was welded that way. Go to www.tinmantech.com and check it out , they also sell a torch and tools that are very reasonable.

 

Get yourself a Henrob. well worth the money. I have used it to reskin the roof on my Cougar take and tack weld small spots at a time to keep the distortion down. Actually before you start Practice Practice practice it will allow you to see when things start getting weird and when that happens you have gotten things too hot. take a break have a beer let things cool off...

Dawg

 

I have patched large holes with gas, I weld about 1 in and then hammer with a backup dolly to straghten out the patch then move on. when done the patch was flat and needed little to no sanding. did use a small tip and small rod. I am no xpert but I did not cool the weld it did cool down while you are hammer welding. Ed ke6bnl

 

That's what I do - don't have a mig. Weld short runs, hammer / dolly while hot, let cool. You're good to go.

 

use a 00 tip and 1/16 rod, set the gas low, around 5 and 10.

Gary

 

out of curiousity,,are you using flux mig wire without argon hooked up? cuz thats the only time i have ever really had trouble with brittle welds.

 

gas welding is easy and fairly forgiving
use the smallest tip you got, 00 or 0
butt weld only
leave a consistant gap between panels a little less than a sixteenth
use clean filler rod same thickness or less than the material you are welding
the weld is easiest to work when hot but can be worked cold too
if you work it hot remember it will continue to shrink as it cools
have someplace handy to set the lit torch, a hook or something near that won't burn you or your shop down, weld hammer weld hammer weld hammer...
everyone will develope their own technique
and it really is not that difficult,
hell, if an all thumbs dope like me can fake it
anybody can.

maybe someone should do an extensive Tech thread on this?

http://www.jalopyjournal.com/forum/showthread.php?t=15652

http://www.jalopyjournal.com/forum/showthread.php?t=63615

 

I try never to have a gap when welding sheet metal. It is just not necessary in order to get good penetration on the thin stuff, and can exacerbate warpage. I don't quench welds unless I need to cool a thick piece of steel down for handling. Quenching helps you shrink.....but when welding you are already shrinking. You need to stretch, not shrink. I never get in a hurry to hammer and dolly while the metal is hot during welding....you can stretch the weld when hot, warm or cold. Here is an article (with links to others) that might help:

http://metalshapers.org/101/jkelly/index.html

John www.ghiaspecialties.com

 

I gas weld patches with an 000 tip and 1/16 rods, and I think it works OK. I can hammer the welds quite a lot without cracking them.

 

I use a 000 tip and cut pieces of .030" wire from my MIG welder to use as filler, work small areas, hammer & dolly to pull it down.....works great.

 

I did collision repair for a living through a few years in my younger days but learned with mig welders. I never really got the hang of weldingthin material with gas due to the high heat saturation. I just seemed to be warping more than welding, but I did see an old timer do it this way once and was completely in awe. He also used heat to shrink select areas on panels that were warped here and there. That was cool! I caught Chip Foose doing that on Overhaulin the other day.

Uumm, is Overhaulin OK? Did I just let the dirty laundry slip?

 

Might also try to use some of the heat sink clays that are available to suppress the warping. I personally have used a spray sold by the matco guy. Just taped the area to be welded sprayed on both sides then pulled off the tape and welded worked great.

 

Oxy/Acc is a very nice weld to work with as far as relative softness, compared to Mig. Control of warpage is key. In the past, I have tacked with Mig, just because it's so much easier. And then filled in between the tacks with Oxy/Acc. Like the guys have said here, an inch is about as far as you can go before putting down the torch and picking up the hammer and dolly. Firm dolly pressure, medium strikes with flat-faced hammer. You'll see the weld flatten and the two pieces of metal really become one. Keep an eye on your overall contour and correct it before you continue. If left wavy or high or low, it'll only get worse. Never use water unless you need to dramatically shrink something. I use 00 tip and 2-3 lbs pressure.

 

Seems everyone assumes that the panels we're talking about can be reached from the back. Try welding a body (albeit a VW) that's been shortened 14 1/2" using a torch, where most all of the welds can't be reached from behind. I used the wet rag to keep everything from warping (as I said in my first post), & I had to use very little bondo all the way across the top, down both sides of the top, & on the 1/4 panels. I'm just saying....
~ Paul
aka "Tha Driver"

If you can't take the heat, get out of the nuclear reactor.

 

Me too. No problem. Works good, lasts a long time!


pigpen

 

Do you use any sort of flux on the rod, or just rely on the flame to consume any oxygen around the weld?

 

Paul wrote:

Seems everyone assumes that the panels we're talking about can be reached from the back. Try welding a body (albeit a VW) that's been shortened 14 1/2" using a torch, where most all of the welds can't be reached from behind. I used the wet rag to keep everything from warping (as I said in my first post), & I had to use very little bondo all the way across the top, down both sides of the top, & on the 1/4 panels. I'm just saying....
~ Paul
aka "Tha Driver"


Hi Paul,

I've done lots of welding experiments trying to control warpage (plenty of VWs). The upshot in my opinion: controlling warpage is over emphasized, straightening the metal after welding is under emphasized.

Sure the warpage should be attended to as it happens by bumping with a dolly or stretching a little bit, but trying to eliminate warpage by cooling is a recipe for more bondo...which is fine, but if you want to do your best work, you accept the warpage and deal with it mostly after welding.

To gain access to the back side, sometimes you have to cut out metal to reach the outer skin with a dolly. Well worth the effort sometimes, sometimes not. Other times you may need to use a home made tool like my planishing hammer in the attached picture.

John www.ghiaspecialties.com

 

In use...

 

a nuetral flame with clean metal will fuse the weld cleanly

I aint no metalugist but I'm thinkin' the problem of which you are referin' is due to the electrical burning of steel in arc, mig and tig welding

 

Thanks. Actually any melted steel has the potential to rapidly oxidize. The flux on arc welding rod is meant to float on top of the puddle and "seal" it from the air. Same for the inert gas used in Mig and Tig. I too am just learning to weld with a torch, and I've seen conflicting advice that had me a little confused. On the one hand I had the impression I'd need to keep dipping my hot welding rod in the can of blue powder I got from the welding supply store, but my work seems to be just fine if I burn right past it.

 

metalshapes here on the hamb does alot of hammer welding (he did on my shoebox chop) and he has one of those mobile planishing hammers

 

I have never heard it explained exactly like that before.
it was my impression flux was meant to lift impurities, mainly oxides
and in the case of arc welding to also produce a gas shield.

 

No flux but best to get some oa welding rod at the local dealer.

 

How is o/a rod different from TIG rod?

 

The Henrob is what I use for hammer welding. Use OA rod as mig wire is a different alloy made for modern car metals. Old car patch panels are almost always mild steel, just like old bodies; ask the vendor to be sure.

With some practice you can butt weld with a Henrob without any filler rod which makes the next step real easy.

Of course the modern way is to glue them on but you still need to tack (or rivet) large panels

 

I think you need to re-tread my post. I used *very little* bondo & I didn't have to cut out the back panels to do dolly work. I've been doing this shtuff for 35+ years, & while I don't have all the fancy tools that you do my work is show winning doing my dollying by hand. Bottom line is the less warpage you get the less dolly work you have to do. A wet rag can save a lot of work in some cases so I didn't think folks should be saying to *never* use water.
~ Paul
aka "Tha Driver"

Remember 1/2 of the population is below average.