Welding Tips and Tricks

I'm planning on welding in a small patch panel on the roof of my old car. I went down to the metal supplier today, and I asked for 1018 cold rolled. I took the drop piece they sold me which has some light surface rust on it home, (holy hell steel has gone up since I last bought some, $20 bucks for a 2x2 piece...). When I got back, I was able to see it is actually a piece of 18ga (40 thou) 4130.. Patch piece is about 3.5 x 3 inches so not very big, but the cut out piece had a lot of pitting so I opted to cut and weld rather than fiberglass over it.

With that said, this is a non structural weld just a patch panel.
Was planning on running er70s2 either .035 or .045 wire. Any reason I should not weld this up like its mild steel and move on to body filler and paint?

Thanks!

It will be just fine with that. Or, you could use SilBr and braze it in with your TIG. Either works.

Sweet thanks for the reassurance CJ