Space around T-snout question

[Dad]

I'm relining an existing chimney with ss. The existing chimney is covered with 4-6" stone, then cinderblock, then the clay tile. The thimble is 8" diameter and 22" deep. I've attached a T-snout and all is well except I'm concerned that that length unsupported is not good. (photos 1 & 2) I wrapped a 1" x 9' fireproof rope around the outside but that seems very very flexible and isn't doing much (photo3). Should I be concerned about the 1" gap all the way around? If yes, what should I put in there?

 

[bholler]

I'm relining an existing chimney with ss. The existing chimney is covered with 4-6" stone, then cinderblock, then the clay tile. The thimble is 8" diameter and 22" deep. I've attached a T-snout and all is well except I'm concerned that that length unsupported is not good. (photos 1 & 2) I wrapped a 1" x 9' fireproof rope around the outside but that seems very very flexible and isn't doing much (photo3). Should I be concerned about the 1" gap all the way around? If yes, what should I put in there?

I typically pack with insulation about an inch back then fill with chamber tech over that. Insulation behind a trim collar attached to the wall can work as well

 

[Dad]

I typically pack with insulation about an inch back then fill with chamber tech over that. Insulation behind a trim collar attached to the wall can work as well

To make sure I understand, you're saying to pack rock wool insulation from the back of the thimble to about an inch where it comes out of the wall. Then fill that last inch with something like a Chamber Tech, or fasten the trim collar to the wall (with I'm guessing a high temperature RTV silicone sealant). Is that correct?

BTW Thanks for your help!

 

[bholler]

To make sure I understand, you're saying to pack rock wool insulation from the back of the thimble to about an inch where it comes out of the wall. Then fill that last inch with something like a Chamber Tech, or fasten the trim collar to the wall (with I'm guessing a high temperature RTV silicone sealant). Is that correct?

BTW Thanks for your help!

I don't pack the whole thing full no but you could

 

[Dad]

Thx

 

[neverstop]

I typically pack with insulation about an inch back then fill with chamber tech over that. Insulation behind a trim collar attached to the wall can work as well

Is there an alternative to chamber tech or a place to buy a smaller volume? I just need to fill over the ceramic fiber insulation (2400F direct flame rated) with it. I don't want to buy 5 gallons just to use 2-3 cups worth.

 

[bholler]

Is there an alternative to chamber tech or a place to buy a smaller volume? I just need to fill over the ceramic fiber insulation (2400F direct flame rated) with it. I don't want to buy 5 gallons just to use 2-3 cups worth.

You can try regular mortar or furnace cement but it will probably crack

 

[neverstop]

You can try regular mortar or furnace cement but it will probably crack

I have a trim collar, would putting high temp rtv on the back of that to adhere it to the wall be sufficient?

 

[bholler]

I have a trim collar, would putting high temp rtv on the back of that to adhere it to the wall be sufficient?

That would probably be ok. Just keep the rtv as far from the actual pipe as you can

 

[neverstop]

That would probably be ok. Just keep the rtv as far from the actual pipe as you can

Castable Refractory Cement

RUTLAND Castable Refractory Cement is an exceptionally strong dry-mix cement that chemically sets and dries as hard as brick. Just add water!

rutland.com

^^is that a suitable substitute for chamber tech?

 

[bholler]

Castable Refractory Cement

RUTLAND Castable Refractory Cement is an exceptionally strong dry-mix cement that chemically sets and dries as hard as brick. Just add water!

rutland.com

^^is that a suitable substitute for chamber tech?

That will most likely crack as well with the expansion of the stainless