TIG 16ga steel sheet

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I'm trying to weld steel sheet metal and I'm blowing through it.  All I can think of it too much heat, but pretty sure I'm on my lowest setting, have my pedal set up to 10-40amps.  I'm on DC, do I need to be on AC?  I thought that was only for aluminum.  I'm putting holes in it so I'm putting out too much heat, maybe moving too slow.
Reply:Let's see the pic? It's all about reading the puddle, but if your blowing through then it's really hard to read, more like jam in the rod lol.  You don't want any gap in 16 gauge or it will be much harder to weld
Reply:You need more amperage (60 or so) and travel speed, and probably larger or more frequent filler dips. Are you able to use a copper or aluminum backer on the joint?
Reply:Why don't you try welding in smaller runs.  .5"  at a time.  Move around from place to place.  Take five minute breaks in between every half-dozen Welds.    this will help you achieve what you are trying to do until your skills set catches up
Reply:Originally Posted by kmattickI'm trying to weld steel sheet metal and I'm blowing through it.  All I can think of it too much heat, but pretty sure I'm on my lowest setting, have my pedal set up to 10-40amps.  I'm on DC, do I need to be on AC?  I thought that was only for aluminum.  I'm putting holes in it so I'm putting out too much heat, maybe moving too slow.
Reply:I would go with smaller filler and use the correct amount of heat. 60a or so. Are you using filler at all? No gap, no bevel, and clamp tight to the table if you can. If you're really off on your sellings you could weld the part to steel, but aluminum or copper could survive 100's of amps, even with a big gap. Actually, after you've blown a hole in your part you can clamp a backer on there and fix it.SqWave 200Millermatic 190Airco 200 ACHypertherm PM45Boice-Crane Band SawVictor O/A
Reply:no gap? You have to have a gap. You need to tac weld all along the joint to maintain that gap. Atleast tac every inch, or .75 of .5 inch. That sheetmetal will expand like crazy. If you dont have a gap, the sheetmetal will bind big time, crashing the two edges into eachother and causing it to rise or crater as the two plates expand into eachother. Welding sheetmetal is a mess, no way around it. I still got warpage when using .040 tungsten and .040 SiBr rod brazing them. I could get it all tac'd down without warping but going back over them, connecting the tac's, half inch at at time, bouncing around, it still warped. This has been a while but I recall using 20-30 amps. Just barely enough to flow the bronze on contact. I ended up not butt welding anything ever again. I first hem everything in a press brake, then weld the hems and get a really nice result.
Reply:Thanks Jimmy, I'll try the gap. Should it be a thin blond one, or a thick curly Mediterranean one?SqWave 200Millermatic 190Airco 200 ACHypertherm PM45Boice-Crane Band SawVictor O/A
Reply:Originally Posted by BrazinThanks Jimmy, I'll try the gap. Should it be a thin blond one, or a thick curly Mediterranean one?
Reply:I'm not the OP, just trying to inject a little humour. I've have built a few hundred stainless and aluminum boxes out of 18, 16, 14ga without gapping, but not always as cleanly as I'd like. You can certainly count on a bit of warpage, but if your material is laser perfect, and you can clamp things during welding you can use it to get where you're going. More clamps, heatsinks and skill are always helpful.SqWave 200Millermatic 190Airco 200 ACHypertherm PM45Boice-Crane Band SawVictor O/A
Reply:deliberately creating a gap on sheet metal welding ? ........now i have heard of everything. .i know many dozens of tinknockers who have spent many decades each trying to never have a gap and beating any gap that even starts to form tight again. thats why they call tin knockers tin knockers. the beating on sheet metal all day long. of course they have it tacked every few inches. still got to beat any gap tight as it forms. sharp tungsten and small narrow welds to limit heat warpage. you want small (narrow) welds for low warpage. you fill a gap and you put 10x more heat in the joint. never ever use a tungsten that no longer has a sharp point. not sharp and you get a wider arc and wider weld and put 10x more heat into joint.usually only weld a inch or 2 at a time and stop and beat joint tight all day long, bang, bang, bang. we millwrights had to work next to tin knockers. they definitely are a noisy bunchLast edited by WNY_TomB; 05-05-2016 at 02:25 PM.
Reply:Originally Posted by kmattickI'm trying to weld steel sheet metal and I'm blowing through it.  All I can think of it too much heat, but pretty sure I'm on my lowest setting, have my pedal set up to 10-40amps.  I'm on DC, do I need to be on AC?  I thought that was only for aluminum.  I'm putting holes in it so I'm putting out too much heat, maybe moving too slow.
Reply:Are you on DC-?
Reply:16 ga is not very thin. You could even weld that with 6013 stick if needed. So maybe the OP has some problems with his technique and maybe the equipment is wrong for the job. For instance what size tungsten, how is it ground and what size filler? What kind of joint? How about some pictures?
Reply:Originally Posted by Michael rayconsider a mig?  they do fair on sheet and if you'll do lots of spot welds you'll reduce the warping. we stuff a wet towel behind thin sheet and do lots of tacks..seems to work pretty good. we do lots of body panel replacement and our paint and body guy taught me that...works pretty good.  not dripping wet but more than damp.
Reply:kmattick - How often do you bugger the tungsten? When I got started I thought I was doing OK, but when I got someone else to look over my shoulder they pointed out my space between tungsten and metal was too far. If you're so close you accidentally dip the tungsten in the puddle that's probably when you're close enough. If you almost never bugger the tungsten you're either really good or too far away.Some other things that can indicate your space is too far:1. How long before you see a puddle? More than a few seconds to puddle 16 gauge is too much. I want to say 3 seconds is probably the max if your amps are high enough.2. Size of the HAZ (heat affected zone). If you feel the weld looks ok but the HAZ is big you're too far from the metal3. Do the welds look shiny or dull? Mild steel won't get very shiny but when you close the gap they get a little more shiny. This is a self-discovery thing .4. What's the back look like? If it's crusty, scaly, that can be an indication you're moving too slow, from too much tungsten space and/or power too low, and the back gets too hot.It's a bit counter-intuitive, but more power, as close as possible = faster travel, less total heat in the metal.Another thing I figured out for me - as I would proceed through a weld I was increasing the gap without knowing it. I'd start close to the metal, and after a few inches back away. The HAZ increased and the puddle got bigger.If you're tungsten is too far away you sit in 1 spot longer waiting for the puddle and can burn through. Sorry for taking so long to get to the point but your challenge is probably a symptom of other things that are hard to detect by yourself. Cheers.I'm a hobby welderFixing up a 67 CutlassHarbor Freight MIG flux core thingEverlast iTig 200 (I like this one)
Reply:Get your filer metal in there. Move faster and keep your arc short. I tig 16g frequently with scratch start. It can be done.JasonLincoln Idealarc 250 stick/tigThermal Dynamics Cutmaster 52Miller Bobcat 250Torchmate CNC tableThermal Arc Hefty 2Ironworkers Local 720