Then you are putting out more than 60Amps. When you say 60 Amps are you talking about the Primary (power in) or the secondary (out put) circut.
Rule of thumb is .001" of filler OD = 1 Amp so 3/32" rod needs around 90 Amps. Thats not an exact figure just a starting point.
What kind of Amp selection do you have on the machine?