Took the upper gate off tonight...
My tool of choice for removing spot welds is a 3" x 1/16 cutoff wheel. I also use the premium wheels made for stainless steel. It's worth the extra money when you don't have a brown cloud in the shop, like the el cheapo wheels leave, nothing but resin wearing away.
The upper layer of metal will start to turn blue when it gets thin and hot, letting you know you're getting close to the next layer. When you have a blue circle with shiny metal in the center, you are now in the second layer, grind around the blue a bit more and pry the layers apart..
With all the spot welds removed, here's what we find inside...
Note the deep pits. The big problem with just welding a hole closed is you don't know where the next pit is lurking, ready to break through your new paint.
Funny, with all the rust and scale inside, then you find this area of bare steel nice and shiney..
The inside will get media blasted to insure there is no more lurking issues and then epoxy primered before re-assembly.
Here's a better look at the shape we'll need...
