Attn welders. Any tips on patch panel welding?

I'm gonna be welding in some patch panels on the roadster body tomorrow. It's my first time! Took a welding class at the local JC and when doing a butt weld on some fairly thick sheet metal we would heat the edges of the metal to a cherry red and then enter the rod. Is that the way to do it on much thinner sheet metal or would that cause too much warpage? Please school me! Any help is much needed and greatly appreciated!

 

NO!!!!

it's all about keeping the temp DOWN! a tack here, a tack there. otherwise you will be warping the crap out of it.

 

Huh? Tig welding? Search is your friend here!! Lots of threads on this..

What welder you using?

 

u should practis on somthing elsa
keep it cool as shooter said

 

So, just warm the metal edges, hold the torch and rod away, warm the rod then bring it down and melt the rod?

Oxy/act and yes, I'm gonna practice on some scrap 18ga first.

 

If you are gas welding it make sure your panel fit is perfect or as close as you can get. Use a neutral flame and just get in quick form a small puddle and dip the rod then get out quick. Move a few inches and tack again keep tacking it every inch and lightly hammer a dolly to keep it straight. after you get it all tacked fill in the gaps just make sure you skip around to spread the heat. GO SLOW!! and if you blow a hole move on and come back after it cools.


Good luck and practice a lot

 

I am a believer that most good welders can't do sheet metal right! Yeah, they can join the metal together, but it is what's done afterwards that is most important. Most welding schools don't give enough instruction on doing very thin metal, I guess it's not important in most all welding jobs.
You should do some research on old bodyshop methods of joining sheet metal. Get Frank Seargent's book called "Key to Metal Bumping" or Ron Covell. or the Tin Man's videos. That will give you a better idea of how to do the job.
As mentioned, any kind of welding will warp the thin metal. The trick is correcting the warpage after the welds. This is done with hammer and dolly, NOT compressed air, water, or anything else done to cool the weld. Doing hammer and dolly work is a feat in itself, that takes lots of practice.
Give you a REAL short verison of what's happening: The welding process shrinks the metal along the weld bead. All the processes do this, TIG, MIG and gas. You must hammer the weld bead directly ON the dolly, to stretch the area back into the poper configuration. Not as easy as it sounds. Gas is easiest to do, the weld bead is softest. Tig is Next, MIG is the hardest bead, so it's a bit tricky to do. It tends to crack if you dont' have enough penetration, or work it too long or hard.
Some guys work the beads as they go along, hammering after each tack, or stitch of weld. If you're good, you can do it all in one shot after the entire seam is welded. Either way is acceptable, just skill levels dictate how you should do it.
Gas welding is probably the best for seamless panels. You can actually work the hot bead with hammer and dolly, and flatten the bead, stretch the weld area, and smooth the panel all at once, making a seamless repair. But it takes lots of proactice, esp. on the flatter panels!

 

very good explanation chopolds.
do what he said. probably one of the best described i have read in a while.
and remember the key, lots of practice!

another thing is to practice "fixing" the practice parts you have messed up. this way it gets you better at fixing any mistakes during your final run.

 

Hey,

You may wanna pratice welding metal that isn't the same thicknesses together since that's what you'll be dealing with when welding patches onto an old body panel. I'd go with a 00 torch tip, clean it before you start, gas set at 5lbs. oxy at 10 lbs. and a good netural flame. Try for fusion welds, and only add rod where you have poor fit ups & gaps. Keep your tacks widely spaced and always watch for heat build up in the panel. If you have an area that's tough to weld out, or wants to sink on you, try and weld it from behind the panel, and straighten it as you go. I like to hammer and straighten as I go so the panel is always in good shape/alignment rather than repair damage done from the welding, especially on low crowned panels.
Once you're at it awhyle, you'll work out what works for you and what doesn't, but books or videos won't teach ya this, ya gotta get dirty and burn yourself a couple times

" Spending a nation into generational debt is not an act of compassion "

 

http://www.weldingtipsandtricks.com/

 

Try this link... http://allmetalshaping.com/showthread.php?t=2577

Heck, look at all the different threads on this site... http://allmetalshaping.com/index.php

You do have to join to see the pics. Some really talented folks there and some good how-to stuff.

 

I have found that if you wet a towel with cold water, ring it out, then set it or clamp it about 6-8 inches way from where you are welding, it helps keep the temperature down emmensely. Another way is to open the garage door while it's still cool out (morning or evening) and start welding.

 

Any coach builder will tell you it's got to be welded with gas.

Mig and tig welds are to hard and you can't work the metal at the weld point.

I know this is true, but I use a mig, cuz I am not proficient with gas. (I just can't find the time to practice).

 

Once you're at it a whyle, you'll work out what works for you and what doesn't, but books or videos won't teach ya this, ya gotta get dirty and burn yourself a couple times

True enough Rex! But for beginners, sometimes it is a big confidence booster to actually SEE how it is done, and see how the correction works. How much time/how hard, the sounds of the hits, etc. When ifirst started, I could not believe it could be done, even after reading about it. The first video I saw with a pro doing it, I was amazed! Even after working in various shops for 5 years or so.
The key is definately practice! Proper tools are a big advantage for a beginner, as well. Good hard hammers and dollys, NOT Chinese junk, or HF specials. Good ones have the proper balance, hardness, and surface finish to make the job easier, so I think they are imperitive for a beginner, you won't get frustrated as quickly.
Also, I know it's fashionable to bash trying to metal finish TIG or MIG welds, but it can be done. I have done it. Not nearly as easy as gas, ( esp. MIG) but if those welding methods are all you have, you can learn to make them work. "sometimes!" Again, maybe not for a beginner, but with practice, you can do reasonably nice work with them. Tig I think is almost as easy as gas, BTW.

 

Old school......gas weld with soft metal rod then hammer / dolly flat.....do not use water unless you have about 20 years experiance...practice on some scrap pieces the same thickness as you are going to use to get use to the heat and rod.....One thing I learned is to space the pieces apart slightly, this will reduce warpage and push. I know I will get a lot of comeback but using clean coat hanger wire seems to work the best.....make sure you remove the coating....most people dont and it makes dirty welds. Oh and make sure you practice, practice, practice.......

 

Heat shrinks metal. Think of the weld seam as a drawstring on a duffle bag. When the string is pulled the bag wrinkles up. That is, in essence, what is happening to the sheetmetal when two panels are welded together. The shrinking (shortening) of the edges of the panels at the seam as a result of the heat from welding is what causes the warpage. The seam (panel edges) are now too short for the panels. Hammering (crushing) out the weld stretches the seam (panel edges) back to the proper (original) length for the panel. A simple rule I go by is "if the panels fit properly before welding them together then they should go back there after successfully reversing the affects of welding." Welding does not fix poor panel fitment. I TIG steel panels and find the weld to be very ductile and durable and fairly easy to keep the heat affected zone down to a minimum. Hands-on experience will naturally build confidence but not without its challenges. It is sheet metal and will, from time to time, humble out even the most confident and experienced craftsment among us. Good luck and remember, its just sheet metal.

 

I weld corners and other places that can't be hammered first. These places can shrink without warping if done first. The next welds will shrink and warp but a hammer shot will spread the metal and remove the warp. Tack with the widest possible distances between tacks and fill in between after hammering the tacks. Keep tacking and hammering and pretty soon it is welded solid.

 

Hey,
Coat hanger wire contains just enought carbon to be very useful when welding sheetmetal, and besides, whata you gonna do @ 1600 hours on a Sunday when you run outa AWS wire? Jus' remember, it's gotta be 100% (Extra Virgin) coat hanger wire, not the tawdry stuff!

I can remember having a very heated disagreement with a welding equipment salesman 'bout 1978 about the value of welding sheetmetal with a ''squirtgun'' (Mig welder). "how do ya work the panel once it's welded, the mig weld is as hard as chromemolly" I asked? "Work the panel? ya just weld it out, grind it flush, and fill over it" he said. The salesman said "all welding of sheetmetal will be done this way in the future" "Horseshit" I said, "tell that to the guy rebuilding old Packard or Caddie sheetmetal" Yet again, I was wrong..........

It's Sunday, did ya weld on the Tee today & howd in go?

" I like the old millenium better "

 

Great thread. Subscribed. Hopefully I can get it fired back up. With respect to my welding lets just say I have a lot of hair on my knuckles. All I have is a miller mig and a stick welder to work with so I'm sure the combination of that and my inexperience ill be asking many questions.


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Mild steel wire is about 60,000 psi steel, most mig wire is 70,000 psi steel, Chrome moly steel is 90,000 or more. Mig welds aren't as hard as most people think! when welding sheetmetal I use mig because that is what I have. Usually I grind down my welds almost flush before I stretch with hammed and dolly, that way I have less metal to move before I get to the shrunken parent metal along side the weld. This works for me!

 

I beg to differ, mig is hard as nails, TIG is no harder than the parent material, can be worked as much as the parent material and can be finished with a file without ruining the file.

 

Wow....lots of different methods. I just weld it all up all at once unless it's a big piece.....then I will stop and planish it and continue on. Like on this fender bottom.



The fit has to be pretty tight......if you accomplish that you won't need filler rod. The edges will just melt together . I keep a piece of rod at the ready just in case though and only use it if necessary. Also learned not to have square corners. If you have square corners it will blow through when you get there. Now I drill 1/4" holes at the corners and then cut out the bad part. That way I have a radius that won't blow out.
I would agree with practicing on some scrap before you actually start on your body. Angle the torch back at about a 45 degree angle so you are preheating as you go. Put the heat on a spot and as soon as you get a puddle you can kind of just push it along the seam. If you get it down where you don't use filler at all you will end up with a butt weld that won't require any grinding at all.



Once you get the hang of it it's way faster, easier and less work than MIG.

 

Check out David Gardiners YouTube video he goes by the name " mindover" on this sight and allmetalshapers.com and metalmeet.com check them out I am sure they will help.Doug

 

If all you have is MIG equipment to use be aware that MIG wire is not all the same. Might take a good counter man and a special order at your local welding supply or some extra 'net research but softer stuff is available.

Ed

 

Standard mig wire is er70s..
70k psi tensile strength..
Esab and other mfgs have developed soft wire for bodywork...
Commonly marketed by the name "easy grind "
It is so soft that they will not give it a psi rating !
Warning label on the box cautions against using it for anything other than sheet metal repair....NOT for structural welding...
Great stuff..grinds right down and hammers flat...
Not disagreeing with the posts about gas and mig being better.....but this product makes it simple for the average guy...

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Tig...not mig...lol

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While this is an old thread, this is the kind of stuff I enjoy. I have had my own Mig for about the last 15 years, and got pretty proficient with it on panels.

I recently bought a Henrob, and have been trying to use it. I have read everything I could, but just couldn't quite get the hang of it.

I was at a trade show at work, and Dillon/Henrob had their booth set up. I got some hands on training, and it has made a world of difference. There were just a few tweaks to my process, and my I made noticeable improvements. Still have a LONG way to go, but its once again fun to learn a new process.

Books and vids WILL HELP, but find a live person that knows how!

 

Do I need to tack some braces to keep her square. I know I'm gona have to remove most of the pans.


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Brace it until you think you have enough support!
Then brace it until you think you have too much support !
Then brace it some more!!!!
Dave

 

Been setting up my garage for a spare miller 210 I have at our shop. I have to buy a new gun which I found online for 160 delivered but local it's 200-300. Should I be worried about the online price? It was from cyber welder??? Any comments concerned appreciated.


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