I don't know who suggested adding a cooling fan to my el cheapo box, but thank you. I ordered a high volume 110 fan, boxed it onto the back of the unit with sheet metal and screws to force air through the unit. Then I added some cheap rubber feet to the bottom of the box to get it off the ground and add a little clearance for air flow out the bottom.
HOLY COW! It is possible to weld more than a few inches at a time. I've been working on converting a boat trailer into a flatbed in spare bits and pieces of time over the last couple weeks. I got more welding done in the last hour than I got done in the last week. The machine did start to heat up on a two and a half foot burn, and I had to stop and let it cool off for a couple minutes, but it never shut off, and if I was a better welder I probably could have kept going. It had that feel.
Now to scroll down and find the thread and thank the person who suggested it directly. This machine has never been more than the lightest duty hobbiest machine before. Its actually suitable now for some continuous light duty work. Yippee!!! Yahooo!!!
Thank you again.
Its still a cheap welder with limited power and limited settings, but DANG! Its more than jsut a toy now. The fan and box look like a shade tree cluster, but it works.