MG Car Repair: floor pan replacement 1975 mg midget, pop rivets, hole punch

Question
Hi Howard
you have helped me many times in the past, hope you can work your magic again. I would like to know to proceed with floor pan replacement, trunk floor repairs etc. I can do the welding myself that is no problem, but really concerns me is what to look for when removing the rusted sections, that is how they put together, which pieces are flanged, which are not etc. the car is rusted at all the usual spots except the sills which are in great condition.
Thanks in advance.

Jim

Kent, Ohio

Answer
Hi Jim,
If you are talking about an MGB you need to either sand blast the edges of the floor pan or wire brush the area to ID all the spot welds. Then use a spot weld bit to drill out all the spot welds. After you remove the old floor pan you need to grind all the leftover spot welds flat. Then use a air hole punch around the edge of the new floor pan and drill and secure the floor pan down with pop rivets and then weld in the holes you punched. You can either drill out the pop rivets and weld up the holes or just leave them in place.
If you are only patching the floor, the air powered punch has a crimping tool on the opposite side so you can put an offset in the patch or the floor to keep the floor flat. I have never done a trunk but it can be patched the same way after you remove the gas tank.
Howard