From: djb@invalid.com   
      
   On 12/12/2025 00:52, Jim Wilkins wrote:   
   > "David Billington"  wrote in message   
   > news:10hf7il$2erku$1@dont-email.me...   
   >   
   > I've seen the videos of production of chain and it's electric resistance   
   > butt welded from what I've seen.   
   >   
   > What diameter wire or rod are you talking about if you TIG weld it. I've   
   > butt welded quite a few items in the 3mm to 5mm region with TIG, not had   
   > to try larger or smaller, and found the surface tension holds the molten   
   > metal in place and forms a nice joint sometimes with a small filler   
   > addition.   
   >   
   > --------------------------------------   
   >   
   > A half round groove in a firebrick, cut with an angle grinder or chop   
   > saw, might help hold the link in place and confine the puddle. Metal   
   > spacers could support the one or two links that join it.   
   >   
   The last weld of this type I did on 3.2mm CCMS and the guy I did it for   
   made the jigs in plywood, I just asked that he relieved it locally next   
   to and behind where the joint was so any wood burning wouldn't affect   
   the weld. IIRC it had about 6mm either side of the join and 4mm behind   
   and there was hardly any charring of the wood as it was argon shielded   
   as well while the weld pool was at its hottest and during post flow as   
   the weld was cooling, the weld only taking a couple of seconds plus the   
   post flow time. With this type of butt weld I've never found any need to   
   support the weld pool as the surface tension of the molten pool seems to   
   produce a nice cylindrical joint if no filler added or barrel shaped if   
   filler added. I guess if you added loads of filler it might drop but   
   that's not needed.   
      
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