I once repaired a broken exhaust on an old Fiat 125 I gave £30 for so, I wasn't gonna shell out for a new exhaust, using a baked bean tin,Over the years, with many old motorcycle and some car systems, I have found a good patch repair on exhausts to be gun gum in the hole, cover with a laminated patch of at least 3 and up to 7 layers of aluminium foil smeared with more gun gum, then a top patch similarly with sections cut from the side of aluminium drinks cans and layered with gun gum. Clamped usually with a couple of jubilee clips. Might not have the structural strength for a fully cut pipe, but could be braced by adding some rods outside the patching and using extra clamps. Or making a stronger sleeve/ top cover for the repair out of heavier sheet to start with?
gun gum, and 3 jubilee clips, it was still holding when I got rid of it nearly a year later, some bodges can last quite well!