Thimble to wall and pipe to thimble air sealing...how

[Darkwing]

Hello every one...
I ditched my used but free Englander 25PDVC and got myself a US Stove 5502m/KP130 on the latest Tractor surprise deal...
Hearth pad is build and ready for the stove, APC backup battery is charging...
And now comes the moment of truth...cutting into/through the wall...
I got a Dura Vent thimble and several pipes with that stove...
But when i look at the thimble, it has enough "play" between the pipe opening to pass pieces of paper when pipe is pushed through...and with a gap like this, i can even open up a window in winter...
And the Thimble towards wall looks like same issue...it is bend on the sides to keep a nice gap behind the thimble towards wall...how in the world can this be air sealed?
i get it, that i can put tons of stone wool around the outer thimble to insulate that against wall cavern...
But outside/inside wall to thimble and pipe through thimble...i need ideas to air seal that...
Please help...
And any ideas on top for a thermal brake in outer thimble pipe?

Thx in advance

 

[kenora]

I just filled the gap with red high temp rtv.. at least there is no air gap now


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[Wooden Head]

You can also get high temp black RTV. For something that is easily removed, I've used flat stove gasket and silicone tape. The flat gasket is wrapped around the pipe( the ends held together with a small piece of aluminum tape) and slid up against the opening/gap. I use the silicone tape (wrapped around the gasket) to hold it in place.

 

[Darkwing]

RTV? never heard of such thing...but will google it...thx...cause i was afraid normal silicone would just melt and run away or burn...
How warm do these thimble get in general?
Are they touchable? jut to get an idea what to expect...

 

[kenora]

Rtv room temperature vulcanizing.. get one that's labeled for high heat.. and my thimble gets to be about 155f at full blast.. hot but not dangerous .. this per heat gun.. that's the hot spot

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[Darkwing]

@kenora...so you screwed and caulked the thimble flush to the outside plywood wall and caulked also the exiting pipe to the thimble?
I am pretty irritated, that my thimble on both sides of the wall is not flush like a board...it is bend in towards wall to leave half inch void...
Any idea about why they might did that?!

 

[Darkwing]

Soooo. Thimble and outside air intake are through the wall...and i caulked the heck out of them to get it air tight...
This RTV stuff is great...thx for the tipp.
Now time will tell...
Thx to everyone

 

[tbear853]

I just clean surfaces with alcohol, let dry, apply high temp silicone rtv.