Floorpan repair

[Michael Nugent <nugentmd@gte.net>]

Getting ready to do my first MIG welding - repair of the driver's floor. 
Does it make any difference if I attach the patch from the bottom or from
the top?  (I'm thinking more about water accumulation than strength.)

I intend to cut a piece from another car that's 1/2" bigger in all
directions than the hole I cut out, so there will be overlap.

Mike
Renton, WA