My footwells are rusted through on my 68 coupe and i want to replace them. I cant tell how they are secured. Does anyone know if these are bonded in with an adhesive or are they tacked welded on? These are the 12" x 24" footwell, not the entire floor

 

I don't think it was bonded in. Don't think that technology existed back in 68. Most likely spot welded in. I am in the process of restoring my 68 FHC and I think I must have a photo of the new floor panel exposed. If I find it I'll post it.
Bill.

 

The foot wells are welded in. Might be time to check the sills (especially at the forward brace area) since they usually develop rust before the floor does.

 

Your foot wells were originally spot welded into place. Though the best and most original repair would be a proper spot weld, I doubt you'll find a restoration or collision center with an OEM quality resistance spot welder capable of fully reaching over the massive sills to access the weld flanges. Your best option is to simply "plug weld" the panels into place. Traditional mig plug welding takes a little practice. You can likely rent a basic mig welder or elect to hire the work out. An even better new development is silicon-bronze mig welding. Offers strength while reducing heat warpage issues. Plus, it's extremely easy for newbies to master. Check it out online. The process utilizes .030/.8mm CuSi wire and 100% Argon gas running through a traditional basic wire feed welder. Some automotive panel bonding adhesives are very strong and simple to use but I'd stick with a quality plug weld and better yet silicon-bronze. Wish I'd had this newer technology available when I replaced my footwells some 20 years ago on my '64 E.

Bob in KC (spot/mig brazing instructor/sales rep)

 

I would say Mig plug welding is your best bet, as I found it reasonably easy to master when replacing the boot floor and rear valance on a 1980 XJ6 I once had. The alternative is aerospace quality rivets and bonding like modern aluminium Jaguars are assembled with.

 

Hi racerxf12004,
Welding the foot wells on your car can be tricky. If you want to keep any kind of originality I suggest staying away from the self piercing rivet (SPRs), or any of the very capable bonding agents available for collision repair. The rivets don't look original at all, and you should not use the structural adhesives without rivets or some other type of fastening or joining process. Plug mig welding is probably the most used method because of the simplicity of the process. However, make sure you use a mig welder with a spot timer. Once you adjust this feature, you will have plug mig welds that are very simetrical and similar in size and penetration to each other. Unlike lotibob, I would recommend staying away from silicon bronze wire and mig-brazing. Yes, mig brazing is a bit cooler than mig welding (If you have a welder with mig brazing programs).Silicon wire will give you the same structural strength as brazing rod. And like brazing rod it will not fuse with the metal. It lays on top of the surface. This wire was meant for welding galvanized metal without burning away the sink coating. If you are going to mig plug weld use standard copper clad steel wire E70S6 .023 diameter with Agon/Co2 gas mix. The small diameter of the wire will help you weld a bit cooler, but it will fuse to the metal. If you want to spot weld, again as lotibob said, it will be difficult to find a shop with a resistance spot welder that has welding arms large enough to reach the weld area. The best that you can hope for is a shop that has a resistance spot welder with a single sided spot welding gun. Don't know if you can find one for rent, but you should be able to find a reputable body shop that will do it for you using that process. Make sure to clean all sides of the metal and spray some weld through primer on the mating faces of the metal panels. Weld through primer will protect the metal from rusting since you will not be able to paint the areas of the panels that touch each other. Good luck.