Header Repair Question

I found my loud exhaust leak last night, and it was a strange one. The #2 tube is situated about 1/4" above the r/h side if the front crossmember. Under the tube is a self-threading 3/8" bolt that holds the starter wire loom in place. It seems that the bolt started turning itself back out of the hole on my trip south last week.

The bolt eventually came in contact with the header tube and vibration caused it to penetrate the tube. The head of the bolt was just inside the tube, and engine vibration/movement caused it to push/tear a hole, appox 1" diameter, in the bottom of the tube! After I finally located the source of the problem I was really shocked to see the damage. Weird problems just never cease to amaze me, especially on performance cars.

The headers are Hooker Super Comps. Also surprising is the thinness of the tube. When they call them thin-wall headers, they don't mince words.

I hope this very expensive header can be repaired. What is the metal used? How should it be repaired, especially considering the thinness of the tube? A small piece of metal will need to be pieced-in, probably about the 1" diameter of the hole. I have a very large steel fabricating shop next door to my garage, but I would like to get some info from experienced members of the Forum beforehand.

A new set of headers, including coating would probably cost $700-$800 (or more), so I hope this hole can be repaired. Headers are low mileage, coated, very clean, and in excellent condition. Any advice will be appreciated.