How to make an exhaust pipe thicker?

Question

Long story short: my exhaust pipe snapped into 2 pieces right next to a flange connecting it to an upstream piece. Since it's too close to the flange, I cut the flange off and inserted a piece of pipe there instead, bridging the 2 pieces of pipe. I used high temp epoxy as an adhesive and then high temp silicone to seal it off. The heat of the exhaust burned through both and the pipe fell off.

Round 2: new piece of pipe, but this time I'm using exhaust band clamps similar to this one.

Problem: the smallest exhaust band clamp I can find is for 2" OD pipe. My pipe is 2" OD at one end (the downstream side), but 1 3/4" OD at the other end (the upstream side). This is because the 2 pieces of pipe that I am joining (what used to be 2 pipes joined by that flange I cut off) are 2 different diameters. I've been to other auto parts stores, none have a smaller band clamp. I've tightened the 2" band clamp as far as it goes, it's still completely loose.

Question: how do I add about 1/4" thickness to the outside of my pipe so that the band clamp fits? It needs to be:

1. something hard (so silicone is out)
2. must resist exhaust heat
3. must be either rollable by hand to cover the exhaust pipe or already tube shape

Is thin sheet metal able to resist exhaust temperatures? What kind of sheet metal? Aluminium? Stainless steel?

Answer 1

Fixed it. The "band" part of the clamp comes completely off rather easily, just remove both bolts, and then there's 3 "curvy metal things" that work together to make a clamp (once it's bolted down).

At each end of the "band" are 4 holes (the band is folded back on itself at each end for added strength). Just drill 2 new holes at one end about 3/4" lower than the lower holes, unbend that end of the band so you can refold it in such a way as the upper holes line up with your new holes (for added strength). Install, and marvel in the simplicity of it all.

And always remember...

Answer 2

I'd wrap a sheet of steel around it (if it's rusted through, you've probably got mild steel already?). Conveniently tube-shaped bits of thin steel can be easily obtained by looking in your recycling bin - baked bean cans! (or fizzy drinks cans if you need something thinner)

You should also be using proper exhaust putty, not silicone or epoxy. It's designed for the purpose and is actually made harder by the heat.