Yes, that is good advice. BUT, if you're just doing sheetmetal, you won't be using ANYWHERE NEAR the welder's max power, which would be fine for a lighter cord. Point in case, at work, we have a welder that we use for welding exhaust systems on vehicles. We have a 25 foot extension cord that's just 12 gauge wire. Now, that's completely undersized for that welder's max draw. BUT, at the highest, we never run higher than range 3 (for thick exhaust pipes). Now, if you're doing sheetmetal, probably range 1 or 2.... So an extension cord that's had the ends replaced will work just fine... And no matter what, if you cant use it with a 220 welder safely, then you DEFINITELY can't use it with a 120 welder on the same work piece because you're drawing double the amps....
