Mustang Frame Rail Repair And Strengthening

After cutting out the drivers side toe pan this is what I found. This page will focus on the frame rail repairs but I also opened up the torque box and strengthened it. See the drivers side torque box page for that.
I'm pretty sure this is what the majority of the inside of the frame rails looks like. I won't be replacing this frame rail as it's good enough to repair. There is a quarter inch steel L bracket running from the frame rail to the end of the floor supports so there is ample strength.
I sanded as much of the rust as I could, then chemically treated it, primered it, and finally gave it a coat of Rust-Oleam paint. I didn't have any rubber undercoating available so this is how it will have to be. Good for another 20 years.
Here is a shot of the 12ga metal support patch I'm about to weld in to the driver's side frame rail right under the toe pan. You can see part of the quarter inch steel L bracket which runs the length of the floor supports. I don't have a before shot, but the remains of the old floor support ran up past the L bracket. I cut that out and ground a grove to fit the 12ga patch into.
You can see the patch fitting right behind the steel L bracket into the grove I created. The torque box is in the way on the other side so it was hard to clamp this piece in place.
And finally welded in place. Most of my welding may be overkill but welding is just so theraputic I can't stop! :)
The passengerside 12ga steel patch. A bit smaller then the driver's side, but it will do the job. I don't have a before picture here either, just forgot to take one. It was also the remains of a bad weld job on the floor support. For corrosion protection you see that I'm trying to keep all the area that isn't being welded painted.
This side was easy to clamp down as there was no torque box on the other side.
Welded but still needing some weld grinding.
Here is a shot of the passenger end of the frame rail and the floor supports. There is rust damage where the frame rail meets the floor support that I'll throw some makeshift patches in. This picture actually shows the shot after I did some welding.
Here is the rust of the floor support. I cut the immediate sides to get to the rust at the bottom and they were in need of repair also. On the passenger side I also have a quarter inch steel L bracket running underneath so the floor support isn't doing any real work here so the repair will go easily.
I cut out the rust and ground the area down to clean metal for a few welds. The metal you see in the hole area is the L bracket that runs underneath.
Put a couple welds in around the hole area. Decided not to actually fin the hole in with a patch. I'll throw in a steel rod running along the side and some 12ga patches for the floor support sides and we will be good to go.
I'm going to weld this 1/2 inch steel rod at the edge for added strength. There's no real method to this madness, just weld till I'm satisfied.
Patching the side of the floor support here with a small 12ga steel plate. This will tie into the plate that was show earlier.
Just a shot of the patch clamped into place. Move along.
The other side.
So here is everything welded. The width of the patch on the right side a bit thin but no matter, it is enough to put a spot weld on when the floor pan comes down. It works, doesn't have to be pretty.