I thought I'd post and maybe save someone some time if they make a similar mistake.

I got gas for my welder some time back, but I was still using the flux core wire -- no problem so far. In fact the combo of flux core wire and gas allowed me to weld in some places where I thought it was going to be too windy.

I finally ran out of the flux core wire and put on a spool of .030 solid wire.

Hard to get a smooth arc, no penetration. Beads looked like steel caterpillars sitting on top of the metal.

I was perplexed for a couple of days, then I had a Doh! moment. I had forgotten to change the welder to positive ground when I changed to solid wire. All better now.

Here's hoping this saves someone else some aggravation.

regards,
Leon