Thanks for the compliments both of ya...
Yes, as you saw from some of the pics, I cut out the bad, drew a templet from cardboard. Now I used a Torchmate to do the cutting to create the patch. My old way, same as most. would be to transfer the templet to a flat plate and gas torch or plasma cut the patch. I do very much taper the edges of the old frame and the new patch, so much so that the weld wants to burn through to the back side. Main thing then is to focus the weld to the thicker metals and sweep across the thin metal in the middle.
Then doing the opposite side goes easier since you now have more material to absorb the heat.
I grind the weld with a 4 1/2 inch grinder. Grind till the weld is still slightly higher than the frame metal. Then identify any low spots in the weld seem. Now focus on the low spots with a pass of the Mig welder. This filling and grinding may take a few repeats. Once the whole weld is just slightly higher than the frame, get a brand new 40 grit flap disc. The grinder spins at some 20.000 rpm, with little or no pressure focus on the weld, you will see the weld smoothly decrease right to the height of the frame, keeping the grinder moving back and forth at all times.
The key... NEW flap discs, it has to be new, if it aint new for this final grind, you will have to put pressure on the grinder which then the flap disc will try to follow the shape of the weld instead of the weld giving into the grinder. Yes, you will change the flap disc rather quickly, it only works when the disc is like new. BUT, the disc is not wasted, it'll still work perfect for all you other needs so you still get a full life out of it.