Stack sealant failure

[cmw]

See the attached pic. The sealant fell off partially exposing the opening where the stack vents into the chimney. I also see a white cotton(asbestos ???) material between the stack and the wall of the chimney.
My questions are:
Should I duct tape this exposed area as a temporary fix until I get a sealant to cover it up? I also have metal (aluminum) tape.
What is the sealant material I should use for a long term fix?

Thanks for any tips.

[tk03]

That looks like a product called Kaowool (non-asbestos). No need to tape it. You could go to your heating company and if they have any dry chimney sealer they would probably gibe you a small amount. About two cups would do it. Of not buy some vent pipe sealer at the hardware store. You could use the same stuff they use on wood stoves.

[cmw]

tk03........... thanks a lot for the info. I wasn't sure about the material to use.