Well, I welded in the first small patch. This was for that hole in the dashboard I discovered after removing the windshield. Overall it went better than I expected, although I have MUCH room for improvement.
The first thing to do is cut a pattern for the patch from cardboard. In this case, a noble Mt. Dew case sacrificed its lid. My patch pattern wasn't the greatest, but it worked OK.
Next, cut the patch metal. I picked up a small sheet of sheet steel from Lowe's. I just traced the pattern on the steel, and cut it with a 1/8" cutoff wheel on my grinder. Easy money.
You can see the patch is a little wonky, but I thought it was OK. In the future, I won't leave any gaps larger than 1/8", since it takes a lot more time to fill those. I need to pick up some big magnets, and some vice grips for some of this sheet metal work.
Next come the tack welds. Then more tack welds. Then, when you burn through, even more tack welds. Until they all run together. For those who are interested, I'm running 0.025 solid wire with C25. I think I may have had the gas a little on the lean side this time. I have had it set at about 20cfh. The welder is set at 1 and a hair under 30.
Then you grind it off all pretty. When I get around to it, I'll fill this and smooth it out with the fiberglas type body filler that gives the welded seams even more strength.
So, not a total disaster, but I definitely am just beginning to learn how to do this. I figure if I really screw up this part, it will be an easy fix in the future. I may end up replacing the entire dash panel. That can be done without completely gutting the car. But I'd rather take a stab at this, and keep as much of that old iron as possible.
I did find one other very small looking spot that rusted through as well. I will probably have to hit the whole edge of that dash panel with a wire wheel and see if I cant track down all the little spots. Hopefully there's nothing any worse than what I've found so far. The only problem is that the rust you see is only a small fraction of the rust that may really be down under there. . . And there's only one way to find out.