silicone roof flange???

Hi yall its been a long while, i built a new outdoor shed for my furnace this summer and im thinking about getting on of them silicone roof flanges they have a metal ring around the bottom and are made of orange silicone the dealer says they are for hi heat applications , BUT i dont know if they know what they are talking about.. i burn a little wood in the fall and every now and then i "burn out" the creosote in the pipes and i have seen the pipes turn red before so im a little concerned about the silicone burning, anybody ever used these before???? thanks for the help and may your winter be mild

I know in automotive applications silicone is typically used in high heat areas - like spark plug boots or wires. I had a set of silicone hi performance plug wires which sat less than 1/4" away from a 700° exhaust header for many years before it finally dried out & cracked ...... so with that in mind, I would think silicone would be a good choice as far as heat goes.

If you get it red hot, it'll burn - no question.

Sun resistance is another aspect though, but if it's designed for a roofing application I would think they took that into consideration when manufacturing the boot.

I sealed my indoor draft inducer seams with black silicone hi-temp. I had an overfire and the black paint on the pipe was smoking. I was worried about the silicone but it held up fine. Like Smitty knows, if you go to red hot against it though, I don't think it will take it. Is this the pipe going through the roof? Is it insulated double or triple wall pipe?

thanks guys....

its a single wall black stove pipe going through a tin roof, thats where im having my leak issues, thanks

I think they make a copper-seal RTV silicone, that is even higher temp rated. LIke 1000-1200 degs. i think.

Permatex Ultra Copper is rated to 700° intermittent .... so if it glows, it goes. Double or triple walled pipe would be the solution there.

I fly remote controled airplanes as a hobby and I have silicon exhaust extensions on all of there exhaust pipes to help direct the oil and grunge that comes out of exhaust pipe away from the aircraft...I have never had one burn...and believe me the exhaust temps on the RC plane motors get VERY HOT!

they do indeed but even using 30%nitro and running it hard the temp is bout 400ish. i check the supre tiger and novarossi with a digital temp infrared...

getting the single wall dull red vs bright red is different too but it will indeed compromise the life span..

the rutland pipe silicone is rated to 2000 deg...comes in caulking tube size also

I use a silicone roof flange seal. It works great and I seal the seal against the pipe with Permetex Red Silicone out of the tube. I run single wall tin pipe from my coal stove. At the stove the stack temp can get up to 450. 16' to the roof and the pipe has cooled to 170 degrees. This stove pipe is in my shop and goes through a tin roof. But the Silicone Roof Flange in question here has performed flawlessly for five years now. It's amazing how much heat is actually lost through the pipe and into the shop and that is where I want it. Albeit it's at the ceiling but the heat is in the building and it's a beautiful thing.

Hope this helps...........

Lisa

Poconoeagle wrote:the rutland pipe silicone is rated to 2000 deg...comes in caulking tube size also

I've used Rutland's 2000f mortor in a tube. Works good. Not sure if it's the same thing as their RTV or Silicon....

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