He's very right about leaving the welder running between welds and I'll tell you why. It was a hot day when I was welding and I thought it would be a good idea to turn the welder off. It was like 4-6 minutes between welds. After a bit the welder shut down and would not run again. I took to Norco to get it fixed. When they called me about what was wrong they told me it was the thermosistor, a device that shuts down a overheated welder but in my case I fried it. They told me they could replace or bypass the circut. I had them bypass it, figured I could run it normal and it would be ok. When I went to pick it up I was stunned at what they wanted for the cut and splice job...$160!!! I should have told them to stuff it but I paid them and vowed to NEVER go back. Yes, it did work but I could have got a new one from Harbor Freight for that. I buy my welding supplies form OxArc, ACE, and where ever else. Lowest price for flux core wire right now is Lowes', $44 for a 10 lb spool of flux core.
The welder is still running, in fact I'll be useing it here in a few days to start welding on my bike