You may be right about the wire getting welded to the liner. Come to think about it when it stopped working I had to cut the wire off at the roll and put the wire out of the sleeve with a pair of pliers. At first it was hard to pull and then suddenly came easily. The wire may have just broken off leaving a piece of wire welded in the middle. Its encouraging about the part maybe being Tweetco. I assume the "T" logo on the liner is for Tweetco and the numbers behind it are 45-40.
I normally stick weld everything but years ago I did work for a company that sold cast aluminum furniture and I bought the welder for the argon gas. It worked fine for that purpose but now I mainly use the welder for welding sheetmetal.
Thanks for the info.