[ i tig everything , i tack every inch , then start at one side of the panal and weld continously to the other if i stop its because i ran out of filler material just pick up some more and keep on going , i use .030 mig wire as filler material (I know a lot of you will say this is insane ) i still get my panal gaps as tight as possible , i tack every inch and weld about 3/4 of and inch and grind it right away I still start at one side and go to the other but i dont jump around 18 ga ?
Sometimes you have to make custom dollies, or cut something out and weld it back when finished. This was a great thread, it was really interesting reading all of the different welding techniques.
I like to TIG everything, but I also MIG sheet metal, and I learned this way from a killer professional custom body guy, and this guy is awesome. if joining two pieces together, butt joint, make sure they fit perfectly with the same size gap as the gauge welding wire (for instance, we use .035)-eastwood and other companies sell badass clamps for this. Tac in a few consecutive places. "Stitch" weld the panel approximatly 6 puddles (meaning, overlapping tacks, or make it look like a tig weld, however you prefer to explain it) and immediatly cool it with compressed air. Continue to do this until the weld is finished, grind and DA. Now, everyone has their own way, but this way works out pretty damn good for us, I've seen amazing things result from this. The main benefit is that it is fast and works out pretty good. There are better ways, but when time is a factor and you want to reduce the amount of time required to do the job without dramatically reducing the quality of the work this works out great. The other thing I was taught was to make sure the weld seem is just a little below the rest of the surface, no more than a .0625 though, (because of the possibility of holes in the weld when ground) to allow for a thin coat of duraglas, which is water resistant. That way if any moisture ever gets behind the metal, it can't get through microscopic holes and start to pop the body work or paint from the metal. I'm still working on my TIG methods, but I always try to break a panel where theres a lot of shape, which when welded greatly reduces the amount of warpage. I do the whole tac/hammer bit, and then weld small sections at a time and hammer. So far so good, but haven't really attempted large flat areas yet either.
oh, and I was also taught to grind the weld seam down to the same thickness as the base metal to help prevent the seam from "photo through" when finished.
I learned on gas. I have hammer welded and braze. I always had some degree of panel speciality you had to deal with on every weldd. I never liked the newer systems. I just had to learn to live with the newer systems becuase it was faster. There is something about doing it the way you first learned even if it takes longer.
first off I juse an off the shelf from home depot lincoln electric mig pac I've had for about 10 years. I used it for years with flux core before I discovered gas. worth the extra expense. I'd prefer to be able to tig, but the money's not there yet for the unit. I'm a firm beleiver in butt welding and minimal body filler, but it's much more time consuming than lap welding panels. takes a good bit of time to fit things and I find that the clamps they market to hold panels don't work well for me. I phyiscally hope the panel in place and tack it up then start actually welding. I like really tight gaps, but when I'm done there's minimal filler needed and generally only in a small shink zone right at the weld. depending on panel size I start with welds about every 12 inches then bisect the difference skipping around a bit. when I get down to about 3 inches it's time to weld a bit and walk away. eventually you can tack the whole thing up with small spots--tedius, but I've found it effective in controlling heat. sometimes I knock down the welds in process, but generally I knock the tops off with a hard stone than finish with a flap disc. hope this helps
falconsprint63 Could you do a test on a scrap piece and take pictures and share it with us. Do one with your method of skipping around and another one just stitch it in line all at once, no need to stop to cool it. I would like to see the back side of the welds to. The reason I ask is, I don't think skipping around helps at all. Grinding it with stone and a flap disk is probably adding more heat then the welding it's self.
i have found if you reverse the polarity and use .023 wire also it helps.......at least for me anyway...........just my 2 cents................O' im no expert...but i did stay at a motel 6 last night.........
I have a project that I just welded and I will try to show what I do when welding sheet metal. I usually weld in 1" increments and re-stretch it as I go. On this project I did not do that, I just welded it and then re-stretched the weld. It really does not matter as long as you re-stretch it. I tacked it up about 4'' apart, then did some hammer -dolly work to get it lined up perfectly. Your fit up is crucial! Then I just welded it up, no skipping or cooling I just welded it. To clean it up and metal finish the weld: I first clean up the weld, I grind down the proud of the weld with a cut off wheel. I use a cut off wheel because it adds hardly any extra heat. I leave the proud of the weld a little high because when hammering on the weld I have noticed it will smash down a little. I do clean the inside a little, mainly so I don't scar up my dolly. After I have cleaned it up, at this point, I will now re-stretch the haz of the weld. (Dolly on) I use a slapper because it has a bigger foot print than a body hammer. You can watch the foot print and when the foot print is a solid patch you'll know you're done. (I hope that makes sense) After I re-streched the haz, I then sand it with either 220 or 80 grit and it's done. There are so many different ways to weld panels, just find one that works for you. This is just how I do it and I thought I would share it with you guys. It might take me longer to do it this way but I will catch up when it is time to do the body work.
Hi Johnny , have to agree with you i was taught by a guy that worked in the r&d at rolls royce tack it up , true it up start at one end and don't stop till you get to the end . This puts a much more even haz in that is easier to work out , The tanks looking good . If people want to see more of it go to http://allmetalshaping.com/showthread.php?t=725
Gas welding is the only way to go on sheet metal. When your hammer welding heat is your friend. Mig and Tig your just constantly fighting the heat and shrinkage. When you get a good feel for hammer welding you don't really have to wait for the panel to cool down much, you just get a feel for how the panel will cool, so it winds up being a whole lot faster. On a good day you get a weld that requires no grinding and comes out smooth on both sides.
Johhny, beautiful job on the tanks. Sorry, I've tried to follow the thread, did you tig the tanks? Great thread.
Just a standard Oxy/Acet. rig 0 tip turn the pressure down a bit from what its at for cutting. run about 1 1/2" flame. The tip and torch are probably bigger than what most people are using for hammer welding. I know a lot of people are using Henrobs or other small pistol grip torches. I learned to do it with what we had in the shop so it probably took me longer to get the hang of it, but the old timer that schooled me didn't see anything wrong with the equipment we had. I usually pull the torch off ever so often to keep it from burning through, but when your on the verge of burning through you get nice penetration and the weld stay hot a bit longer so it seems like its a bit easier to hammer out. hope that helps Tig sure sounds fancy but for non structural sheet metal gas welding leaves the metal as close to a factory condition as possible. Tig welds are a lot harder than gas welds and Mig welds even more so. A hardened weld area can cause problems on large, low crown panels, sometimes you can see a trace of the weld when the panels get hot like in the sun during the summer time. I understand working with what you got, but Most people have a OA torch setup and they usually come with a welding tip and torch so you should at least give it a try. Preferably on some scrap 'til you get the hang of it. Really as far as time involved and finished product nothing even comes close to hammer welding as long as you have access to the back of the panel.
I've been preaching the gospel of gas welding for a while, but Tig welders cost 10 times more so they've got to be better...right?
So I've been told. I'm surprised how many people believe that. However, all of the skilled fender repairmen I know use OA and hammer-dolly, for the reasons you so eloquently pointed out, KrisK.........
Anyone know where I can get 000-W_1 tips for my Victor 100 handle? There is a guy on evil-bay, but he wants to charge me $35 to ship it
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