Hack Weld Solder Sculpt: Project '65 investigation: What's going on with the floors?

Every car has a story, sometimes it's buried under old repairs

Drilling out pop rivets from an old patch done to the floor

Remember when we peeled up the carpet and saw some rust patching?

Well last week a closer examination revealed what it was: riveted tin-bodyfiller-tin goop-sandwich floor patch behind the passenger set pedestal (not great, since that's more of a cover-up than a proper repair. And it unfortunately leaves existing rust to continue rusting, as well as trapping moisture in between the layers of existing and added material. No bueno.

Today, I got in there, removed all the rest of the interior in the back, and got to finding all the old rust repairs, drilling out rivets, removing all the material, and taking a look at what we're really dealing with here.

Driver side front patch, removed

After all, we don't want the floors to leak or rot out the car after we put all this time and green into it. We want it to last for at least another 50 years, yeah?

What I found: 10 patches done via the aforementioned sandwich method, and a whole quarter floor patch done to the driver side front floor. Unfortunately even though the patch panel was correct (as in, was a real '65 Mustang replacement panel, not tin like the others), it too was riveted in with body filler filling the gaps. I removed it.

Prognosis: the metal is unfortunately rusted past the floor proper on where the floor meets the firewall in the front and slightly where the floor meets the wheel tubs in the rear.

Where did the driver's floor go? To Illinois, that's where!

It makes the decision to order the one-piece floor replacement easy, but I think I may need to do additional repairs to at least the firewall and maybe the metal around the wheel tubs as well so that the floor pan has metal to weld to in those places.

Did I say this was going to be interesting? We're officially there :)