tig welding sheet metal

[SundownIII]

Nails,

You've gotten some good advice here. Know it's all a lot to absorb at one time. I'll try to summarize and then make a couple of recommendations.

Tungsten-2% Thoriated is good.
Cup size is fine.
20 CFH Argon gas flow is fine.
18-22 ga material-challenging for experienced/intimidating for beginner.
Copper spoon/backing plate almost essential.
1/2" hole-about as big as you want to tackle.

Get good ground as close as possible to work.
Start with clean, reground tungsten. Popping, I suspect, is coming from a contaminated tungsten.
As Clint suggested, start your puddle off the edge of the hole. Use your filler to control the puddle (.035 Mig wire works well). Move in a circular motion around the hole adding filler almost continuiously to keep the heat down. The more filler you can get in the more "heat sink" you create. Move pretty quickly til hole is filled. If that's not working for you, try doing short runs and stop. That will let the weld cool.

The one thing I didn't see listed was whether you are using a remote control for your amps (footpedal or fingertip control). This would make your life a lot easier. You can then get your puddle started and then back off on the amps as heat builds in the weld. Without it you have to control the puddle with filler or by stopping the weld and allowing it to "freeze".

Hope this helps some. Practice, Practice, Practice.

[jamscal]

James, I doubt your popping has as much to do with turbulent shielding gas flow as it does with air/gas resistance flowing through your square tubing and then "blowing up" or "blowing back" into your puddle and onto your tungsten as you weld your seams closed.

Either try back-gassing your tube (if ultra-clean looks are important) or try drilling a super-small hole somewhere along the tubing to let super-heated air and gas expand/escape as you're closing in your welds.

One of the aerospace guys on here probably has something else that will work but that's a common problem for me when TIG'ing on aluminum tubes in rails or towers or sponsons on boats.

~Clint

None of the tubes are being welded closed. I could be wrong as to the cause, but I still think it's turbulance and perhaps a bit of tungsten touching

Nothing is in a good position, plus I'm putting 16 ga formed channel to 1/8" wall tubing of different sizes together in just about every joint configuration. And it has to be fast. I set it on 160 amps and pedal lower when necessary. But on the plus side they're not interested in appearance except they want small welds and don't want to deal with aluminum mig soot and splatter. Everything is getting powder coated.

They're getting pretty welds for all that though. I'm using this place for practice.

-James

[nails79]

thanks for the replys guys, i am using a synchrowave 200 which i believe has the square wave technology. i am having better luck today, switched to a 1/16" 2% tungsten with a 1/2" cup, and i am using .040" filler rod and i am now seeing the puddle better. on the 22 gauge i have the amps set at 24, and on the 18 gauge i have the amps set at 34, i am using a foot pedal and i am by my self so not sure what the actual amps are im getting to. i have had the argon set at 20cfh all day with no problems, then all of a sudden the arc was very erratic and backed up into the cup and rounded my tungsten what causes this??? thanks

[BWS29128]

thanks for the replys guys, i am using a synchrowave 200 which i believe has the square wave technology. i am having better luck today, switched to a 1/16" 2% tungsten with a 1/2" cup, and i am using .040" filler rod and i am now seeing the puddle better. on the 22 gauge i have the amps set at 24, and on the 18 gauge i have the amps set at 34, i am using a foot pedal and i am by my self so not sure what the actual amps are im getting to. i have had the argon set at 20cfh all day with no problems, then all of a sudden the arc was very erratic and backed up into the cup and rounded my tungsten what causes this??? thanks

I'm not sure about your Amperage settings, so we'll have to wait for SundownIII to comment on that (or you can send him a PM...he always answers mine when he has time), and he's EXTREMELY familiar with the Synchro200, so that will help even more (my only Synchro experience was with a Synchro351 @ 440V and that was over 8 years ago). Whatever you're setting your Amps at is pretty close to what you're getting with the pedal-to-the-metal, as it were. Maybe you could have a friend watch your ammeter while you're welding? My Mom stopped by my shop one day while I was struggling with a particularly nasty piece of aluminum and I asked her to watch for me....not pretty, but there it is.

Your comment about "all of a sudden the arc was very erratic and backed up into the cup" leads me to believe that you "sucked up" a piece of your weld puddle and contaminated your tungsten. There's nothing you can do in cases like this except stop, change or regrind your tungsten, and start again.

I like SundownIII's suggestion for using .035 MIG wire if you have some....it's saved my butt a couple of times on thinner stuff and it was his suggestion that brought it to my attention about 5 or 6 months ago on a different board.

Yes, your Synchro has square-wave technology, and one of the best in the business from what I've heard...far superior to my Lincoln PrecisionTIG 185.

If "seeing the puddle" is a problem you're having and it's actually a case of you PHYSICALLY not seeing the puddle, then maybe we need to put you in touch with Jeff Noland at HTP to see about ordering you a Pyrex (clear) cup kit for your TIG torch. Jeff (the owner of HTP, I might add) will be the first to tell you (as he has/did with me) that Pyrex cups are NOT for every-day use, but on those occasions when you just have that weird angle that doesn't allow you to physically "see" your puddle because of the cup or other obstructions, it is ABSOLUTELY the way to go. If you're having trouble getting your puddle started, then we need to go back to what SundownIII was saying and play with your settings 'til you get it right.

And don't worry: he preaches at me to "Practice Practice Practice" all the time

[BWS29128]

PS: the Pyrex cup kits average about $30...not bad for the benefit it gives you.

PPS: I'm sort of surprised that SundownIII hasn't suggested Lanthanated or Ceriated tungsten to you yet....he's a pretty big proponent of both of them and has turned me on to Lanthanated here recently for overhead TIG'ing on aluminum.

[SundownIII]

Clint,

You're using an inverter machine. That's why I recommend the Lanthanated or Ceriated tungsten. The Sync is a transformer based squarewave machine. The Thoriated tungsten works fine for what Nails is working on.

Nails,

As Clint suggested, I suspect you possibly wicked a little of the puddle up on your tungsten. Won't be the first time, won't be the last, especially when welding like you are.

Your amp setting should be fine. I'm more familiar with the Sync 250 than I am with the 200 but shouldn't be much different. With your foot pedal all the way down, you should get the max amps dialed into the machine. As long as you're able to generate your puddle in 2-3 seconds your max setting is fine. You'll want to back off from there as heat builds in the puddle. Since you've got pulse capability on your sync you could use that to help freeze the puddle, but I think that's opening a whole new bag of tricks. You'll need to play with some similar gauge scrap to get a feel for your own pulse settings and what works for you. The thing you need to keep in mind, you're not doing a structural weld where penetration is all inportant, you're trying to minimize the heat while still maintaining a molten puddle. It's a fine line between the two. As you work at feeding the filler and backing off on the amps you'll hit that sweet spot where you just "know it's right". In doing that vertical fill (firewall) you'll find that you want to use about 25-30% fewer amps than you would if you were filling a hole in material "in position".

Keep us posted on your progress. Sounds like you're making great headway.

PS. Sounds like you're now getting things dialed in. If it makes any sense, I'd just say that you want to use your arc to chase that filler around the circumference of the hole.

[fun4now]

FWIW there have been several articles about transformers going to using the lanthanated and cerated tungstens. i'll see if i can dig them up, seems i remember it also being in the miller blog section of the web site about increased TIG production rates.

[AdamsKustoms]

Tig Welding Sheet Metal

hi everyone new to the forums and new to tig. i have a new synchrowave 200 and i am currently attempting to fill the holes in the sheetmetal fire wall in my car. the gauges range from 18-22. i have adjusted the amps from 10 to 35, tried the pulse feature (no luck??), im using 2% tungsten size .040, 1/4"-3/8" cup, argon set at 20psig with 3 second post flow. having a lot of difficulty with burn through. just wondering where i should set the machine up for this size material. am i on the right track?? any tips for a beginner?? i have gotten a decent grip on thicker material 1/8" and thicker. thanks in advance for any advice.
matt

I think its great that you are tackling your own body work on your car. When it comes to auto restoration work tig welding has some great advantages. There are some instances where it can be a pain to utilize.

One thing you may encounter when filling holes is if the metal is double thickness, paint may be actually trapped between the two layers and this could be causing contamination. Paint on the other side of the hole can cause contamination, as it burns off and makes it way out of the hole.

I would definitely recommend making a patch for the holes you are filling. As HMW mentioned using some .035" wire is a good bet for filler wire. I use a 1/16" tungsten in my water cooled torch, that works good for most sheet metal applications. There are sheet metal plug kits made just for filling holes in sheet metal. These kits have assorted size plugs, if your exact size is not available you can use a step drill to drill up to the right size. The step drill also leave a nice chamfer that deburrs the hole, which makes for a cleaner patch. You can also cut them from sheet for larger holes. Tacking a piece of welding rod to the patch can allow you to hold the patch in place wile you weld. You may need to fusion weld one edge while you hold it in place and then once its tacked use filler rod on the opposite side and then you can finish weld.

Tig welding has advantages on sheet metal repair. I use it all the time when I install new patch panels and make custom sheet metal parts but there are a few places where MIG welding may actually be more advantageous. Filling holes on your firewall would be best done with a MIG. For 1) its faster. 2) if done properly it will transfer less heat to the panel, so less potential warping. 3) not quite as fussy if there is a bit of paint left. Also MIG welding holes with a copper spoon behind the metal works great, holes up to 1/2" can be filled that way. Any larger I would recommend a patch. .023 wire with argon/co2 works great. I have noticed that the smaller MIG welders work best for this type of work.

Hope this helps, and good luck with your project.

[fun4now]

lots of great info, but i gota add one small part.
I have noticed that the smaller MIG welders work best for this type of work.

i had the opportunity to use a MM210 on some 20 gage and it performed as well if not better then my MM135. although you may consider the MM210 as still in the small MIG version.aether way it was an excellent fit for the job. and with both MIGs going at once the job went fast and easy.

P.S. good to have you with us, welcome to the site. looks like you have lots of great info to share.

[Shamrock1123]

I was watching some show on TV and they were filling in various sized holes in auto sheet metal. One method I saw them use on small holes was to take a TIG torch at low amperage and fill the holes with uncoated silicon bronze brazing rod. I havn't tried it myself but it looked pretty easy and blended nice with a light sanding.

[fun4now]

Shamrock1123
I was watching some show on TV
&
it looked pretty easy
always end up in the same statement at some point and yet they almost always end up being some of the biggest pains in the ars!!

i think it looks easy due to the ability to stop the camera and re-shoot as needed.

has any one tried this ?? being as he was using uncoated rod, would he have had to pre-flux it with a past or powder before adding the rod ?
i like the powder better then the pre-fluxed rod's. but i never tried it with my TIG, only with O/A torches.

[Shamrock1123]

My understanding of the process is you don't need the flux like you do for O/A brazing because of the Argon flow while using the tig torch.