we figured out how to tig weld sinks made from copper sheetmetal years ago. I dont remember the grade but I want to say it was "oxygen bearing"
anyway, shearing 1/16-3/32" strips from the same material and using it as the filler rod. using the "pulse" function on the machine, zapping it with short spirts and high amps along with high purity argon made some really nice, strong welds. we would then grind and polish the external welds resulting in perfectly matched color between base metal and weld
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