Thimble assistance needed

[gorsuchmill]

I'm getting some mixed signals on a thimble question. I will be installing a new SS liner into an existing clay lined, stone chimney. In order to connect the T I will have to remove the existing clay thimble, which is a tad too small anyway. Given that the T will be passing through an 18" stone wall (i.e. no combustibles nearby), is it necessary to add a thimble? Or, can I simply patch some refractory cement around the T, then connect the interior stove pipe to it?

Thanks.

 

[Todd]

Call local code inspector to make sure.

 

[gorsuchmill]

There is no local inspector and the sweep I hired suggested he would just turn a 90 at the bottom of the flue to get through the masonry and connect to the stove. Based on the sweep, a thimble isn't necessary; however, I don't have enough experience with him to know whether his recommendation is satisfactory or he is simply trying to cut corners for the install he was estimating.

 

[BrotherBart]

Both me and Forum member Todd did the 90 degree turn straight through the thimble and it works great. Ya gotta be real careful and take your time with the turn so you don't tear the liner.

Edit: If he is talking about knocking out the thimble and then turning the liner through the hole that is reallly suspect.

 

[gorsuchmill]

BB - He was indeed. The existing thimble is just shy of 6" ID, so you'd never get a 6" flue through it. The question is, if you have to remove the thimble to get the pipe through the wall, do you have to replace the thimble or can you simply apply some refractory cement around the flue pipe or T? Keep in mind the void created by removing the thimble is through an 18" thick stone and mortar wall with no combustible material present.

 

[BrotherBart]

Myself, I would just mortor the sucker in.

 

[Randyb]

Another option, which I used, if you remove the clay thimble you should have approx an 8" opening, I replaced the old thimble with an 8" straight SS chimney pipe and ran the 6" through the middle with a packing of KAOwool around the 6" on the end, to keep it centered. It just didn't seem right leaving the 6" floating in the opening by itself, and it will keep the 6" pipe warmer for draft purposes.