Heat Proof Silicone?

[MunkeyBoy]

OK cr*p on my part, I am sure I had found actual silicone that was rated to 12000 deg, but I've lost the will to look now.....

 

For the OP's case though, 300 deg has got to be fine at the roof collar.

Many thanks.

[PaulJ]

Envirograf is not cheap but seems to work very well-so far anyway. Stays flexible.Used it to seal all the joints on the stove and also the collar BUT it says to allow (if memory serves me right) three days cure time per couple of mm thickness of silicon bead. So you wouldnt want to put it on too thick unless it was summer..

[MunkeyBoy]

Envirograf is not cheap but seems to work very well-so far anyway. Stays flexible.Used it to seal all the joints on the stove and also the collar BUT it says to allow (if memory serves me right) three days cure time per couple of mm thickness of silicon bead. So you wouldnt want to put it on too thick unless it was summer..

I only plan to use it under the collar as I'M going to use the heat cement and rope for the inside stove bits.

[ditchcrawler]

How hot does it get under your roof collar?

 

 

MtB

Depends if you go out and leave the air vent open and come back to see flames coming out of the chimney

[dmr]

How hot does it get under your roof collar?

 

 

MtB

It don't get hot at all unless somat is wrong.

Collar bolted to boat...boat a big lump of steel, Collar should only get as hot as the boat roof on a sunny day,

Also flue does not touch collar because you have put stove rope in the gap between flue and collar.

Our collar protrudes slightly into the cabin and its f'in cold at this time of the year and a source of condensation.

 

I bet that other advert for 1200 degree silicone also turns out to be fire cement in a tube!

 

...........Dave

[MunkeyBoy]

It don't get hot at all unless somat is wrong.

Collar bolted to boat...boat a big lump of steel, Collar should only get as hot as the boat roof on a sunny day,

Also flue does not touch collar because you have put stove rope in the gap between flue and collar.

Our collar protrudes slightly into the cabin and its f'in cold at this time of the year and a source of condensation.

 

I bet that other advert for 1200 degree silicone also turns out to be fire cement in a tube!

 

...........Dave

Ahh that's interesting thanks for that.

[kevinl]

I bought this because several people in the past here recommended it, worked for me. http://www.screwfix.com/p/mapei-mapeflex-firestop-1200-c-high-temperature-sealant-grey-300ml/25153

Alternatively this which unlike some fire cement doesn't turn to powder after a few weeks try this, cheap, Wilkos have plenty of shops around

http://www.wilko.com/fireside-accessories/inglenook-fire-cement-1kg/invt/0245770

or I have an 80ml tube (tooth pastes size tube) of high temperature silicone minus 40C to +300C which you can have for free, I'll pm you the cost of postage when I find out what it is if you give that amount to a charity we'll call it straight.

K

[by'eck]

Tried and tested

 

[Stilllearning]

I seem to remember years ago we decided to see how heat resistant some silicone was, by squeezing out a small heap onto the workshop floor, then playing the oxyacetylene torch on it. It just sat there and did nothing.

Can't tell you what sort of silicone it was though.

[Grace and Favour]

I seem to remember years ago we decided to see how heat resistant some silicone was, by squeezing out a small heap onto the workshop floor, then playing the oxyacetylene torch on it. It just sat there and did nothing.

Can't tell you what sort of silicone it was though.

It was heat resistant silicone! ( )

[Stilllearning]

It was heat resistant silicone! ( )

Note to self, think before typing...

[ackdaw]

byy eck beat me to it , i was looking for asbestos type sealing rope , which was used for caulking lead run joints on steel cast pipe years ago and it took me too

 

http://www.vitcas.com/high-temperature-sealants

 

but if youve a large gap you can as such pack several strands of rope around ( says it up to 1,000 f ? ) and push that in tight and finish of the end with sealant , i guess the rope seal would also stand vibration a little better ,

you can get infa red heat detectors you just shine the spot at the heat source and they give a digital read out , their fairly accurate as ive used them on resin mixing and checked the results by a normal heat probe , the infa red ones are instant read out

[Mac of Cygnet]

Envirograf is not cheap but seems to work very well-so far anyway. Stays flexible.Used it to seal all the joints on the stove and also the collar BUT it says to allow (if memory serves me right) three days cure time per couple of mm thickness of silicon bead. So you wouldnt want to put it on too thick unless it was summer..

 

Envirograf does work, but beware that even when cured for the recommended time, the first time it is brought up to stove temperature it emits really noxious smoke for about 1/2 hour. I had to evacuate the boat. OK after that.

[dor]

I've used Delta heat-resistant silicone which is rated as safe up to 300 degC. It will certainly be ok for the top of the flue, and I have used it between the flue and the stove collar as well. On my last boat it had been in place for five years and showed no sign of degrading.

 

On my current boat, when the stove was first fitted the gap was filled completely with fire cement. Last winter the collar cracked soon after lighting the fire. I suspect that because the gap was completely filled with cement the rapid expansion of the flue was too much for the collar and being cast it could not accommodate any expansion. It has now been redone with a layer of fire rope and the rest in silicone built up in two layers.