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Stainless Sheet Welding.

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  • #16
    My experience with thin SS.

    Originally posted by myistar View Post
    I have 2 pieces of 1/8" x 6" x 18" Stainless. I need to weld them up to be 1/8" x 12" x 18".

    Which is the best approach into welding them, so there is no heat distortion and my end result is a nice, non warped piece of metal.?

    I have a Sync.200, so I can TIG/Stick weld it. I also have a MM211, and stainless wire. But I'll have to weld it with C-25,

    I don't want to end up with a distorted piece of Stainless, cause I do not want to waste it, So I do want to hear some of your ideas.
    A couple of months ago I did some 304 tables for a laboratory. Main frames were square tubes 1,57"x1,57"x0,047" (40x40x1,2mm), table tops were 0,063" thick (1,6mm). I wanted to try my Passport, so I got a roll of 308 LSI, and a mix of 98% argon and 2 % CO2.
    Results on samples were poor. Too much heat, distortion, burn trough and black soot. Damage from the spatter to the impolute material factory finish was amazing. Really awfull bead appearence.
    Went back to the gas provider who suspected a contamined cylinder. Having not much time, I exchanged it for another of 100% argon and pulled out the CST to tig it.
    For such thin material I used low amps which were around 28 to 32. Higher travel speeds resulted from using about 42 amps in my tests, but HAZ got at least 2 times wider and wrappage was unaceptable. So I kept em low.
    I used a heat sink, a sheet of 2mm aluminum that was laying around, about 10"x25" in size.
    For support I used a piece of 12" UNP and for restriction a 8" INP. Sheet metal had to be completly welded around the table top contours for sanitary reasons. Using a press brake to confrom the sheet for the table tops was not an option for me in this case, so I made them of square tube frames and then tacked them to the sheet pieces (continuos seams were on the outer corner of the frame tubes) all around in 1/2" intervals. I welded a back suport on the UNP, then welded 20 gauge strips in the middle of the support bar, one side at a time, with the frame previouslly all tacked around to the sheet, I pre-stressed it with 10mm bolts exerting pressure over the tube ends horizontally against the the central 20 gauge strips placed in the midle until the frame just touched both extremes of the support bar. After that I put the heat sink on the assembly just 2mm far from the seam of the weld zone, then the INP over the heat sink and with it, applied pressure vertically with two 10" C calmps over the INP ends (I welded extensions on the IPN bottom ends just to assure simmetrical pressure over the piece). Down force exerted by the INP was quite high, but if I had to do it again I would use a couple of car 1,5 ton car jacks to increase pressure).
    I did weld only 1/2" long seams at a time between tacks, spreading the heat over the piece, working simmetrically from the center.
    Labor was intensive but the end results were quite good. Wrapage was not easily noticeable for the untrained eye, but was there. On the bigger tables, I had to back them in the middle with T bars from bellow, welded to the frame, and then glued to the sheet metal with poliuretane adesive on the table top backside.
    HAZ was about 2mm wide. Finish was with Scotchbrite disks.
    I had to use the remote to fine tune the amps on the CST, and monitor its output with a Fluke 337 for readout.

    For your application, and based in the cited job and my little experience, IMHO I believe you could do well with tig, a thicker heat sink than mine for the case (cooper would work better than alu) and heavy pressure to impose restrictions on the piece. Low amps and short beads to prevent heat build up and minimize HAZ. Peregrine or backstepping techniques do help a lot.

    Regards:
    Jerónimo.

    Traumao è la elètrica.

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    • #17
      easy tig it

      Originally posted by myistar View Post
      I have 2 pieces of 1/8" x 6" x 18" Stainless. I need to weld them up to be 1/8" x 12" x 18".

      Which is the best approach into welding them, so there is no heat distortion and my end result is a nice, non warped piece of metal.?

      I have a Sync.200, so I can TIG/Stick weld it. I also have a MM211, and stainless wire. But I'll have to weld it with C-25,

      I don't want to end up with a distorted piece of Stainless, cause I do not want to waste it, So I do want to hear some of your ideas.
      (you can use a backer like aluminim1/4) just tack together tacks are very close let cool fuse cold and fast little filer if your going to polish let cool do other side same way 1/8 shouldnt move if your cold enough good luck

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      • #18
        I would think that you'd put a lot less heat into it if you zapped it with the MIG.

        That being said, I'd have it zipped up and dressed with the TIG before you had your wire and gas changed over. I'd probably use a setup close to Sundown's, only probably hotter.
        Distortion? Definitely gonna be something, but it's all good given the application. Close tacks. Skip it and zip it, dawg. Don't dally.

        Keep us posted with your results and good luck.
        Maxstar 200DX
        Maxstar 300DX
        Dynasty 200DX
        Passport
        Spectrum 701
        LMSW-52 spot welder

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        • #19
          Everything here sounds good. I would try peining the backside of the weld to get the plate flat..

          Just my thoughts...

          Here's my latest project out of SS
          Attached Files
          Jonny

          Dynasty 300DX
          Esab PCM 1000

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          • #20
            one of my buds does this all the time and he says that the best way to prevent warping is to go slow, lots of small tacks and lots of wet rags. He is pretty good as he has done automotive trim in ss like the windshield trim on antique cars. I forget the gauge but beer can thickness comes to mind.

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            • #21
              1/8" ss

              It's 1/8". Clamp it down the full length of the weld and sear it together.
              Mustangs Forever!

              Miller equipment.

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