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  • sanitary stainless tube tig problem

    welding on 1.5" sanitary tube...I cant seem to get rid if the little welder eye at the end of my weld...machined perfect with a Tri-tool...wiped with acetone...full inside purge...clean clean clean...backing out of puddle slowly...can't seem to figure this out...getting frustrated...any ideas?

  • #2
    Yes. That little eye is cause by weld crater contraction. You mention pulling out slowly. Is that pulling away with the voltage flaring or is that ramping down current? Are you using a peddle or just running a set current? Adding a bit of filler as it's cooling, a slight back step or further progression to thicker material on final filling, and finally just how big of a crater are we talking about? Post a picture. Could be your running to hot it's hard to say for sure?

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    • #3
      using a foot peddle...amping down slow and extending past the end to thicker metal...only running 56 amps...tube is .065...fusion only...no filler...its a very small defect but this is for food grade sanitary application...im still on my practice pieces waiting for materials to be delivered for the project...thank you for trying....and i'm not savy with the computer and pics...

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      • #4
        Ok...another question with those details added, what shape is your tungsten ground to and what size and type are you using?

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        • #5
          i'm using 2% lanthinated...1/16"...ground like your bottom pic

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          • #6
            What sort of cup are you using? Maybe try to increase your shielding gas or envelope?

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            • #7
              old school standard ceramic cup...size 7....35 CFH ....7-8 CFH on inside purge...rest of the inside weld looks perfect...just the end has the eye

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              • #8
                Ok. Do you grasp how that shape requires greater amperage and how a less tapered point would effect the process?

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                Ryan mentioned the cup size and shielding envelope. My second and third picture eludes to that and the effect it would have. If I was to describe what you mention, you are displacing metal but not filling because it's not there due to contraction. Reduce the melting by reducing heat input and you will reduce contraction within the crater as it does contract from a fluid state.

                Your pointy tungsten is the problem in my opinion. And it's just that, an opinion. But if you choose to continue with it, just travel further around reducing the current as you go past the finish line and it will probably cure the problem.

                The higher up the pebble is dropped into the pond the greater the splash. Sharper the knife the greater the depth it's pushed?

                With that said and for the reader reading, a blunter point over a long slender pointed end requires less current to achieve heat input. I don't make this stuff up you, it happens for a reason.
                You have two pieces of thin tube. If you used the picture above for reference, your 56 amps could be reduce to 46 amps and with it a possible decrease to the over heat and melting your experiencing doing a weld autogenously?

                Then again, going past the finish and ramping down the current will probably be enough rather then just stopping when it seals shut. The idea being too continue on and reduce current to minimize the further melting thru the materials depth and thickness or lack of during the contraction of the weld crater.

                Hope it helps. If not, you can't say I didn't try.

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                • #9
                  Thank you for all the input...I will try all these suggestions...And i do grasp the whole shape concept...i appreciate your time and knowledge...I'll let you know what i figure out

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                  • #10
                    I wouldn't close the door on the topic, I'm sure there are other opinions to be shared. But if you break it down in small steps and look at each step that's taken, you'll find an answer and solution to the problem.

                    https://www.youtube.com/watch?v=nMKygGnYoI4

                    I didn't watch much. But I bumped it along to the good part. You want about 13 minutes in.
                    Everyone has a story and opinion. My comment would be, look how wide the bead is, how the welder squeals like a pig, then ask yourself, what have you learned? If you learned something from my reply great, you pick something up from this video great. Still learning is the key. Just don't stop thinking about it.

                    Do come back and let us know. As well good on you for asking a question. While I can't fix a broken welder, I can talk welding as a second language and need the practice.

                    https://www.thefabricator.com/tubepi...rs-fabricators

                    https://www.thefabricator.com/thefab...iables-of-gtaw
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ID:	603463 I tend to over think the stuff maybe? Then again, some don't think enough maybe? There's room for all of us if you ask my opinion. But I'm curious...what else have you heard or read to be the cause and the cure?

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                    • #11
                      Good luck man, let us know what you figure out. It’s hard to throw ideas out without seeing exactly what you’re talking about. I can only pretend to imagine your issue. Personally, I love a big cup for stainless, but use what works for you. I’d like to see some pictures of what you have going on. Something to think about, and I’m just throwing ideas out to see if something sticks, maybe switch to a 3/32 and dress it down to the size you need. Give it a shot and see if that helps your problem.

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                      • #12
                        I only had time to run a few passes today on these tubes...I changed my sharpening to less length on the point...And really focused on the finish line amp drop...It definately helped...By the 4th piece they had zero defects...I just switched everything to practice on some 1' tube and its working perfectly...Thank you for the help...the video was good too

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                        • #13
                          Glad to hear you’re dialing it in. Sometimes those subtle changes are the key. It’s like most things, it’s the little stuff that matters.

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                          • #14
                            I never asked what power source you're using, that will and does make for a difference in arc characteristics. Slight if a steady arc is kept, It can also mean the difference between a melt and wash or a seam blown apart. I suspect an inverter and while it wouldn't change my offering of suggestion, I'll mention it to be mindful of the affects it, voltage, brings effecting the spread of heat, building of temperature for melting and the push of pressure. Sounds like your winning. Feels good doesn't it.

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                            • #15
                              I'm using a Lincoln 200 square wave...I also switched to 3/32" tungsten and steep grind and dropped to 50 amps...I think it all helped ...Thanks again for all of your help...I AM winning!!!!

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