Help With Flue Adapter to Hardpipe

  • Active since 1995, is THE place on the internet for free information and advice about wood stoves, pellet stoves and other energy saving equipment.

    We strive to provide opinions, articles, discussions and history related to Hearth Products and in a more general sense, energy issues.

    We promote the EFFICIENT, RESPONSIBLE, CLEAN and SAFE use of all fuels, whether renewable or fossil.


New Member
Nov 21, 2023
I need to connect this:

To this:

The adapter/reducer attaches to a cut off section of my flue that is drilled in with stainless screws.

My question is: The double walled pipe connects to the interior section of the 10” hardpipe. How do I secure the 2 pieces together? Caulk? Longer screws? any help is appreciated.
Is this for the outdoor fireplace and is that fireplace set up for air cooled chimney. Subsitutes are not allowed there.