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Post subject:Stainless Welding Help
 Posted: Mar 30, 2007 - 12:25 AM #6133
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Joined: Mar 30, 2007
Posts: 4
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| Can anyone suggest a proven technique for tig welding 16ga stainless sheet without deformation? I have practiced a little and can't seam to get it right. I am welding with a sync 200 with pulse and am tacking the seam every 5 in, but still not getting the result I want. Any tips or suggestions in regards to setup, clamping, or amperage settings would be a great help. |
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Post subject:RE: Stainless Welding Help
Posted: Mar 30, 2007 - 01:29 PM #6136
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Power User
Joined: Sep 03, 2003
Posts: 175
Location: edinburgh
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| Hi Garry i would use a 1.6 mm ,2% thoriated [red painted end ] this has a d.c+ current range of 70-150 amps ,keep the tungsten nice and sharp,you dont say how long the seam is that your welding, with material this thin you should be dot tacking every 1/2",the 5"gap you have between tacks at the moment allows for to much movement in the metal inbetween them so as you weld along one sheet may move up and the other down close tacks should eliminate this , also if you can clamp the sheets flat this will get rid of some but not all distortion.Hope this helps aw ra best Marky |
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Post subject:RE: Stainless Welding Help
Posted: Mar 31, 2007 - 12:57 AM #6140
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Joined: Mar 27, 2007
Posts: 8
Location: SATX
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It would help if I knew what grade stainless you're using, but I'll assume it's 304.
Marky has a good start for you, but let me add a few things. First, the tungsten. 2% thoriated is a good stick to use, as long as you grind it to a fine point and keep it clean. If you are having control troubles or tend to dip your electrode a lot, try switching up to lanthanated or trimix. Your local weld supplier will have a few suggestions for you along these lines as well. Second: make sure your shield gas (I recommend argon) is flowing at a rate high enough to cover the weld zone without disturbing the molten puddle (16-20 cfm for a #5 cup with 3/32" electrode). This forces you to use more heat to complete the weld. A common mistake I see a lot is people leave the tungsten too far out of the cup, or they don't use a gas lense to diffuse the shield gas. Either one of these conditions can cause you to add more heat to the weld. Third, weld cool as you can without losing the puddle. Higher grade steels don't dissipate heat well, and the more you put into the work, the more it accumulates and causes distortion. Maybe you can fuse the weld instead of using filler, which requires more heat. I have also had success using copper backings, which take heat away from the weld quickly. Good luck! |
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Post subject:RE: Stainless Welding Help
Posted: Mar 31, 2007 - 05:02 AM #6141
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Joined: Mar 30, 2007
Posts: 4
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Thanks for everyone's response,
Well I am using 2% thor. tungston red stripe 3/32" dia. with a 1/16th stainless filler rod. The stainless is 304 16ga. and its for a countertop, lucky me it was a small section because I warped the heck out of it and now I think I am going to make a dog bowl out of it. I am setting the amps at 75 with a pulse of 10, anyone prefer using pulse or not?
Let me explain the project. The countertop is 60" long and unfortunatley could not afford to buy that 12ga 60" brake and had to settle for the 48", so I have peiced together a 48" section and a 12" section and am trying to weld both together to be seamless. The nosing in 1.5 in and has a backsplash of 4in. I am able to clamp the entire thing to my welding table. Also, I am using a very sharp tungston.
The problem that I am encountering is once I tack, the peice looks great and is acceptable, but once I start finishing the welds, the seam buckles in on itself and warps to hell. It seams like once I start welding the front part the back starts to shrink and buckles. Should I complete the weld on the counter seam before tacking the nosing and backsplash? Is the problem trying to disapate heat from the area? I feel that I am a very capable at welding this, and its frustrating me to no end, I should mention this is my first attempt and anything below 1/8th thick and mostly weld structurals. I guess its just practice, practice, practice. I will post a picture of my next attempt.
Thanks
Garry |
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Post subject:RE: Stainless Welding Help
Posted: Mar 31, 2007 - 05:10 AM #6142
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Joined: Mar 30, 2007
Posts: 4
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| What does Bozak mean by gas lense, do you mean using a glass vrs. ceramic cup? Also what is the best method of cleaning the filler rods before welding, I am getting quite a bit of black oxidation on the weld and am told that my filler rod is not clean. Also I am using Argon set a 20cfm. |
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Post subject:RE: Stainless Welding Help
Posted: Apr 01, 2007 - 05:37 PM #6143
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Joined: Jun 23, 2004
Posts: 67
Location: Rapid City, SD
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The gas lens he's referring to is basically a fine screen that fits in the cup. This will minimize turbulence of the shielding gas and make sure it washes the whole weld area with out any impurities getting in.
I'm not real sure what to clean the filler rod with. I'm kind of thinking giving it a few swipes with a stainless steel brush (or stainless steel wool if you have some), then wipe it down with some denatured alcohol (or other clean substance).
I welded up some duct once that was a pita, I believe it was 24ga. Being warped wasn't a huge deal, but we still tried to make it as nice as possible. Super low heat, I even layed some scrap aluminum a few inches away from the joint to help suck up the extra heat... also made a great hand rest that didn't get as hot as the metal itself.
I can't really think of any "tricks" off the top of my head to help you out, but if I do think of something I'll be sure to post it. |
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Post subject:RE: Stainless Welding Help
Posted: Apr 01, 2007 - 09:32 PM #6144
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Joined: Mar 27, 2007
Posts: 8
Location: SATX
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Basically, heat = expansion, cooling = shrinkage. This is more true in ferrous metals (steels) than in non-ferrous (aluminum). The heat going into the weld has to dissipate, if it doesn't then the heat affected zone expands as the metal absorbs more and more energy. Heat causes metal to expand in size, and this expansion has to be compensated for somehow. Try a simple experiment to see how it works on a flat piece like the counter top you're working: cute two 6 inch long pieces and weld them together using a butt joint like the one on the counter. If you start with the seams parallel, the final work will be warped. This is because as the weld cools behind your arc, it shrinks, while at the same time the HAZ is expanding. The result is a push/pull reaction that distorts the surface of the metal. Now cut another 2 pieces and set them up so that at one end the corners are together, at the other end leave a gap between the corners equal to about 1.5 times the thickness of the metal. Now weld them. It will come out flat, because the gap at the other end compensated for the push/pull effect of heat shrinkage by providing room for the expansion to take place, and allowing the shrinking weld behind the arc to pull the two pieces together.
Now, as far as the counter top is concerned, you have multiple turns on the weld joint. This is how I would do it: First, get some thick copper to back the weld with, like 1/4" barstock. Clamp the work thoroughly, and here's a bonus: if you use aluminum plate under your clamps, they absorb more heat. Tack the piece as you have been, but leave the vertical on the backsplash unwelded until last. If there's a lip on the front, same deal. Weld it last. After tacking, start in the middle of the flat and work outward in short increments, taking time to let it cool after each pass. remember, heat is accumulative and the less you input the better. I wouldn't do any more than 1 inch at a time on .0625". After each weld, let it cool off, aim a fan at it, low pressure air, whatever it takes, just get it cool, preferably back to ambient temperature. Then start again, always working from the middle outward.
Like I said, if you can get away with it try to fuse the joint without filler. It's less heat into the work. Good luck, be sure to let us know how it comes out! |
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Post subject:RE: Stainless Welding Help
Posted: Apr 01, 2007 - 09:35 PM #6145
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Joined: Mar 27, 2007
Posts: 8
Location: SATX
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AmickRacing wrote:
I'm not real sure what to clean the filler rod with. I'm kind of thinking giving it a few swipes with a stainless steel brush (or stainless steel wool if you have some), then wipe it down with some denatured alcohol (or other clean substance).
Acetone is the only thing I ever use. It's good stuff. |
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Post subject:RE: Stainless Welding Help
Posted: Apr 01, 2007 - 10:04 PM #6146
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Joined: Mar 30, 2007
Posts: 4
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Thanks everyone for all of your imput, can't wait to get in the shop tomorrow and have a go at it again. I will post some pics as soon as I finish.
Thanks,
Garry |
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Post subject:RE: Stainless Welding Help
Posted: Apr 04, 2007 - 02:36 AM #6151
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Joined: Oct 01, 2006
Posts: 44
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Garry-
Thanks for posting this thread, I actually learned quite a bit from all those who responded. I work in severa; pharmaceutical facilities and have shyed away from some of the clean welded stainless work that has been bid. I am just getting started down this road. I was wondring if anyone can recommend a good TIG machine to get started with. Both of our MIG machines are Hobart brand, and I would like to stay with that brand if possible (local dealer). Most welding will be done in the shop, but some in the field also, so a mobile machine would be better.
Thanks |
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Post subject:RE: Stainless Welding Help
Posted: Apr 04, 2007 - 04:08 AM #6153
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Joined: Jun 23, 2004
Posts: 67
Location: Rapid City, SD
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Post subject:RE: Stainless Welding Help
Posted: Apr 04, 2007 - 11:47 PM #6156
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Joined: Mar 27, 2007
Posts: 8
Location: SATX
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Yep. The maxstar150 is prolly the bast place for you to start. It's very dependable, Miller backs up their equipment, and it's extremely portable. |
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Post subject:RE: Stainless Welding Help
Posted: Apr 05, 2007 - 03:24 AM #6160
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Power User
Joined: Apr 04, 2007
Posts: 93
Location: Florida
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| I have to begin my visitations to your site here. Right now we solder all of our stainless projects. My boss has purchased a Miller Tig welding machine but I fear that his 'Expert welder friend' has convinced him that it will not work for our purposes. I work for a commercial roofing company and 90% of all our gutters and accessories are stainless steel, anywhere from 22 ga. down to 26. Everything must be solid soldered. Is it possible to TIG weld 26 Ga. to 22 ga. stainless steel? I have Mig, stick and brazed but never touched a Tig machine. We pretty much always purchase 304. This is a huge issue, since the soldering makes me and my two co-workers quite ill. I visited some TIG info sites and related that info to the boss...But we all know that e'xpert friends' tend to rule the day. Any advice will be greatly appreciated. |
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Post subject:RE: Stainless Welding Help
Posted: Apr 05, 2007 - 04:23 AM #6163
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Joined: Jun 23, 2004
Posts: 67
Location: Rapid City, SD
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You can weld 22 and 26 ga stainless together pretty easily (with some practice). The best way I can describe doing this would be keep most of your heat on the thicker metal and "roll" it onto the thin stuff.
I would say, if you're proficient with the other welding operations, TIG won't be super hard to learn at all.
Sounds like that welder friend is kind of stuck in the old days to me. Nothing wrong with the old ways of doing things, but you need to be adaptable to change, especially with all of the technology coming at us every day. |
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Post subject:RE: Stainless Welding Help
Posted: Apr 07, 2007 - 12:51 AM #6182
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Joined: Mar 27, 2007
Posts: 8
Location: SATX
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| Most of my experience with stainless is 304 16ga or 14ga. If I ever got anything thinner than that I would try to fuse it...adding filler just allows too much heat to get into the work. I'd crank the machine as low as possible and take 10 minutes to get a puddle, after that if you have a good tight fit up, it'll fuse like butter. |
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