How to snug up fitting between exhaust can and midpipe?

So, I had to replace my exhaust can and mid-pipe after a crash.

I have two problems with the fitting:

1) the diameter of the midpipe is smaller than the opening of the exhaust can, and
2) I've been unable to stretch the midpipe's diameter. Harder steel, I guess, and I believe I'm using the right expander tool for the job.

Is there a way to shrink the diameter of the exhaust can's opening (even if it means crimping it a bit)? It's made of a softer metal.

 

you can use that muffler bandage goop...
https://www.acehardware.com/departm...c=ds&msclkid=1e32cbdd02b518559c7daee5614b972f

 

Try rolling a piece of brass shim stock to fit the I.D. It’s easier to cut and form than the more common cold rolled variety

 

Graphite exhaust gasket, measure your OD/ID and you can probably pull one up doing a google search.

 

I had a similar problem, so I went to a custom exhaust shop and they said they could stretch anything but titanium for the millimeters I needed. Just an idea.

 

These are all good suggestions. Thanks all.