Hi all,
I am just learning TIG and have a question. I am trying to weld DOM mild steel tubing. I am using thoriated tungsten, ER70S-2 filler and Argon gas . Sometimes I finish a weld and don’t like the look of it so I want to go back over it. When I do it gets all bubbly and sparkly. When finished It looks like pumice rock and is full of pits and holes. I have tried everything, even grinding it down and laying another bead over it but I get the same result. What am I doing wrong?
jason.hwnd
- jason.hwnd
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Active Member
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Joined:Sun Mar 21, 2010 7:33 am
personally, if i want a 'super look', I'll run back over the weld with the pulser turned to a desired setting.
the prep work before the final run (for visual efx) is sanding smooth the electrolysis / etching crap off.
run some good cleaner (I use acetone).
so basically, wire brush, acetone-clean, brush, clean again - let dry - run pulser setting.
dont forget to clean the filler with acetone and the electrode.
i've had more of a hassle with nasty filler metal than anything else lately.
Maybe I'm not doing it right either but these are the steps i took which produced good/reasonable results.
the prep work before the final run (for visual efx) is sanding smooth the electrolysis / etching crap off.
run some good cleaner (I use acetone).
so basically, wire brush, acetone-clean, brush, clean again - let dry - run pulser setting.
dont forget to clean the filler with acetone and the electrode.
i've had more of a hassle with nasty filler metal than anything else lately.
Maybe I'm not doing it right either but these are the steps i took which produced good/reasonable results.
Miller Aerowave
I think I may have backed myself in a corner. after grinding as much of the old weld out as I could, cleaning with wire brush and atone things just got worse. now the weld is totally un acceptable. I tried more heat, less heat, more gas, less gas and I am at my wits end. there seems to be nothing I can do to make it behave. I have repeated the above process 2times now with no improvement. what can I do?
I am seriously considering Oxy - cetylene welding it
Fred
I am seriously considering Oxy - cetylene welding it
Fred
kermdawg
- kermdawg
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Joined:Tue May 25, 2010 8:16 pm
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Location:All over, mostly southwest USA
Whats unacceptable about it? When you were grinding it down did you notice any cracks or anything like that? Whats the puddle doing that is making it unweldable. Are you letting the metal cool down between passes?
Signature? Who needs a F***ing signature?
It looks like a pieceof lava rock when I finish . Full of holes. No cracks but plenty of little pits. As soon as a puddle forms it starts to boil and spit. Then it seems to crawl away from the pin holes that form. I can take scrap pieces on the table and run a nice bead ...without even cleaning it.
kermdawg
- kermdawg
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Location:All over, mostly southwest USA
Sounds like contaminated metal. What happens is your first weld pass, the metal is cool. After your first weld pass the metal heats up and those oils (usually an anti-rust coating from the factory) will float to the service. When you cleaned the metal you probably didnt think to clean the inside, and after heating and cooling so many times all that oil is coming up to the surface from your welding.
If your just trying to remove those pits from the contaminants boiling out, you might be able to let the weld area completely cool down, like cold enough to grab it with your hand for 5 seconds. Then turn your machine up a bit, grab a bit of filler, and move quickly, puddle up and fill in(Think hot pass). If that doesnt work You'll have to grind out the entire weld and start over. New tungsten, fresh clean filler, the whole nine yards.
See if yuo cant post a few pictures. Depending on how bad it is/what the application is for you might be better off just leaving it the way it is. Put it this way-I had the same problem in welding school doing my pipe, mainly cause I wasnt letting the pipe cool down between passes, but my instructor told me not to worry about it and you wouldnt fail most weld tests because of it. I dont know how truthful it is but he is a CWI so he knows his shit.
What are your metal thickness, amperage and gas flow set at?
If your just trying to remove those pits from the contaminants boiling out, you might be able to let the weld area completely cool down, like cold enough to grab it with your hand for 5 seconds. Then turn your machine up a bit, grab a bit of filler, and move quickly, puddle up and fill in(Think hot pass). If that doesnt work You'll have to grind out the entire weld and start over. New tungsten, fresh clean filler, the whole nine yards.
See if yuo cant post a few pictures. Depending on how bad it is/what the application is for you might be better off just leaving it the way it is. Put it this way-I had the same problem in welding school doing my pipe, mainly cause I wasnt letting the pipe cool down between passes, but my instructor told me not to worry about it and you wouldnt fail most weld tests because of it. I dont know how truthful it is but he is a CWI so he knows his shit.
What are your metal thickness, amperage and gas flow set at?
Signature? Who needs a F***ing signature?
If you are welding tubing and covering the end of the piece of tubing that you are having trouble with, you might be capturing the heated air in the tube with no where for it to escape and it is trying to blow out in the last of the weld. When welding racecar chasis. we drill a small hole in the tube close to the end. I have seen a reaction similar to yours from that. Not seeing or knowing what you are doing, I am just guessing. It also will pull contamination to the weld if the tube isn't clean inside and out, including the mill scale in that area, Need pictures.