Taking Care of a Drone

[Blue94]

So all of a sudden my car sounds like a rice rocket (no offense). I got under the car and found the drone to be coming from the center cat. I came here and searched for info (thank you) and ended up ordering all three doughnut gaskets, and new nuts and bolts.

Well today I tackled the project, went fairly well. Got it all back together and guess what....it still drones. I have checked my work and remembered that the two smaller gaskets went on without any effort when compared to the larger single gasket which was a snug fit. I am leaking exhaust from the smaller gasket and have concluded that the exhaust pipe must have rusted down to a smaller diameter.

So, rather than take it to a shop and get new tips and flanges welded on, is there some kind of gasket sealer or tape that I could build up the pipe so the gasket will fit more snug?

Thanks, Dust