Back to the frame, I repaired both side simultaneously but I'll put these pics in order per side.
Passenger before:
(almost forgot to take pictures before I finished cutting.
Started grinding down the metal and cleaning this all up. I used a combination of grinding discs, and wire brushes on a Milwaukee M12 Right Angle Die Grinder. This tool ended up being a life save because it allowed be to grind the inside of the frame as well.
I took advantage of this opening to vacuum out any remaining rust flakes. Sprayed rust converter inside as well.
First piece tacked in, this is 1/8" flatbar.
Fully welded. I had a hard time with the butt joints, burned through a couple times. Much harder welding upside down, especially with not totally clean metal.
I welded the inside as well, which was pretty difficult. Had to grind my welds down quite a bit because they were blobby.
I added a gusset here just some extra strength.
I then realized the metal just forward of where I put the patch was pretty damn thin since most of it had flaked off. So I ended up cutting this section out as well.
Same thing behind the body mount. Had to cut out the gusset out in order to have access for cutting.
Pretty simple process for making these patches.
I welded this piece flush with the existing frame, and then ground it down.
The bottom piece I actually put it inside the frame, I cut it 1/4" larger than my opening all the way around. This way I had a lap joint instead of butt joint and could put a real hot bead without worrying about burning through.
Overlapped it with my original piece and welded inside as well.
After grinding smooth.