Beware Silicone Gasket Cement

[bilvihur]

I re-gasketed my VC Resolute Acclaim this summer, using the Permatex Hi-Temp Red silicone gasket cement.
Big Mistake! The gasket around the damper plate started coming off after only a few burns. I took it apart this AM, cleaned the channel, and re-cemented using a tube of Perkins Black gasket cement (which no matter how much you knead it, nor how big an opening you cut off the spout, always comes out in spurts).
I don't know where I got the idea for the silicone, but I would warn everyone against it on moving parts. I wish someone could recommend a gasket cement that flowed smoothly, in a tube that could get into tight places, but you don't have to squeeze so hard as to split the tube!

 

[Highbeam]

The gasket around the damper plate

So was this the front loading door gasket? Or some sort of internal gasket? I plan to use regular automotive high temp RTV from permatex. Ultra black most likely. For the internal bypass damper gasket there is a special super high temp cement that BK specifies.

 

[Woody Stover]

Standard "hi-temp" red silicone is only good to about 500-600° maybe. The copper stuff is for exhuast systems, and 800 intermittent. I use that for the door gasket on the Buck, that's what was used at the factory. I've seen 1000° (Mil-Pac) but I don't think even that temp would be enough to withstand internal firebox temps.
Yeah, you have to watch it buying furnace or gasket cement; If it's been sitting around a while, it will separate and is hard to mix up again. I've used Meeco Gasketing Cement and Stove Sealer, and I think Rutland has similar stuff. It's the same composition as furnace cement, but it a bit runnier so it will get in the seems better, or in your case, gasket channels. Sometimes, it is too runny for working on vertical seams until the tube dries out a bit.

 

[Jags]

Just for perspective - the stove has to hit an internal temp of 1100F for the reburn tubes to go active on a tube stove. Just pointing out that you are dealing with some pretty intense temps when you stop and think about it.
This stuff is stove gasket specific in application:
(broken link removed to https://www.rutland.com/p/37/e-z-spread-fiberglass-stove-gasket-cement)

 

[Woody Stover]

Just for perspective - the stove has to hit an internal temp of 1100F for the reburn tubes to go active on a tube stove. Just pointing out that you are dealing with some pretty intense temps

If that's the bypass gasket he's referring to, there are some big flames hitting that area when you are ramping the stove up to temp.

 

[Jags]

If that's the bypass gasket he's referring to, there are some big flames hitting that area when you are ramping the stove up to temp.

No doubt. The gasket cement in my above post is rated to 2000F. If that isn't enough, we have other problems.

 

[begreen]

My experience is that some RTV silicone turns to rock when exposed to high heat. This was Permatex Blue IIRC. It was an absolute bear to remove. When I redid the T6 door gasket this time I used Meeco gasket adhesive.

 

[webby3650]

You cannot use silicone on the inside of the stove! It will not hold up to those temps. No way!
Some manufactures use silicone for door gaskets but that's about it. Some stoves are designed in a way that the silicone won't even hold up on the door. If it didn't come siliconed from the factory, it's Ya, those aren't very aggressive. You need a flat wire broomnot likely a good idea to change it, from my experience.

 

[rdust]

BK uses silicone on the door, not sure on the bypass.

 

[bilvihur]

So was this the front loading door gasket? Or some sort of internal gasket? I plan to use regular automotive high temp RTV from permatex. Ultra black most likely. For the internal bypass damper gasket there is a special super high temp cement that BK specifies.

It's the bypass damper, which when open for starting a burn, allow smoke/gasses to go directly into the flue.

 

[bilvihur]

Just for perspective - the stove has to hit an internal temp of 1100F for the reburn tubes to go active on a tube stove. Just pointing out that you are dealing with some pretty intense temps when you stop and think about it.
This stuff is stove gasket specific in application:
(broken link removed to https://www.rutland.com/p/37/e-z-spread-fiberglass-stove-gasket-cement)

I'm going to buy some of the Rutland cement and additional gasket to have on hand. I just wish there was a cement that didn't pre-harden in the tube!

 

[bilvihur]

Standard "hi-temp" red silicone is only good to about 500-600° maybe. The copper stuff is for exhuast systems, and 800 intermittent. I use that for the door gasket on the Buck, that's what was used at the factory. I've seen 1000° (Mil-Pac) but I don't think even that temp would be enough to withstand internal firebox temps.
Yeah, you have to watch it buying furnace or gasket cement; If it's been sitting around a while, it will separate and is hard to mix up again. I've used Meeco Gasketing Cement and Stove Sealer, and I think Rutland has similar stuff. It's the same composition as furnace cement, but it a bit runnier so it will get in the seems better, or in your case, gasket channels. Sometimes, it is too runny for working on vertical seams until the tube dries out a bit.

I'm going to buy some Rutland cement and additional gasket to have on hand. I wish those tubes wouldn't harden up before they're even opened!

 

[Jags]

I'm going to buy some Rutland cement

That was simply one example. There are others such as the Meeco mentioned above.

 

[webby3650]

I would stick with Rutland, I'm not too impressed with Meeco products...

 

[begreen]

I've had good luck with the Meeco gasket adhesive. They key is to mix it well in the tube first before applying.

Update 1/3/2017: Well the Meeco failed after a season of use. The gasket just dropped out of the channel in spite of a good bead of cement still adhered to the back of the gasket. Switched to Rutland for replacement today. It's a much more homogenous mix, not watery.

 

[webby3650]

I've had good luck with the Meeco gasket adhesive. They key is to mix it well in the tube first before applying.

Ya, it's really their cement that sketchy.

 

[Woody Stover]

I re-gasketed....I wish those tubes wouldn't harden up before they're even opened!.

Hopefully the bypass gasket is the only one you have to re-do. I had good luck removing old gasket cement/silicone with an angle grinder with cable-twist brush wheel. You should be able to tell at the store by squeezing the tube if the cement has hardened. Seems like the farm stores move that stuff at a pretty good clip. You might check there for fresher stock, but your stove shop should be on top of it. A small amount of drying won't hurt, but too long and it gets like you are describing, separated, hard and un-mixable. Maybe you can seal your gasket cement tube when you are done, with some silicone!

I would stick with Rutland, I'm not too impressed with Meeco products...

I don't know what Meeco products you didn't like but I'd think it would be hard to mess up furnace cement....who knows though? I've used both brands of cement, off and on. I haven't had any gaskets come loose yet. I did have a Rutland Pro Choice Torque Lock poly brush pull apart on me in SIL's flue last year; That wasn't confidence-inspiring. This year I removed the pipe damper and went all the way down to the elbow, so I wouldn't have to reverse in the middle of the pipe section, but I imagine reversing in a pipe section would sometimes be unavoidable...?

 

[webby3650]

Hopefully the bypass gasket is the only one you have to re-do. I had good luck removing old gasket cement/silicone with an angle grinder with cable-twist brush wheel. You should be able to tell at the store by squeezing the tube if the cement has hardened. Seems like the farm stores move that stuff at a pretty good clip. You might check there for fresher stock, but your stove shop should be on top of it. A small amount of drying won't hurt, but too long and it gets like you are describing, separated, hard and un-mixable. Maybe you can seal your gasket cement tube when you are done, with some silicone!

I don't know what Meeco products you didn't like but I'd think it would be hard to mess up furnace cement....who knows though? I've used both brands of cement, off and on. I haven't had any gaskets come loose yet. I did have a Rutland Pro Choice Torque Lock poly brush pull apart on me in SIL's flue last year; That wasn't confidence-inspiring. This year I removed the pipe damper and went all the way down to the elbow, so I wouldn't have to reverse in the middle of the pipe section, but I imagine reversing in a pipe section would sometimes be unavoidable...?

The Meeco cement doesn't seem to hold up as well as Rutland cement. We use both, I prefer the Rutland for consistency if nothing else..
For the record, I don't think Rutland makes brooms. They slap their name on the same cheap brooms that many other companies do. China I'd assume..

 

[Woody Stover]

I don't think Rutland makes brooms. They slap their name on the same cheap brooms that many other companies do. China I'd assume..

Alright then, which ones should I be buying?

 

[scooby074]

I did the door gasket on my Alderlea T6 with Ultra Copper this year and so far it has been excellent. Still nice and pliable. Much easier to work with than the "water glass"
type gasket adhesive. Id have no problems recommending UC silicone for a door gasket, not in direct flame, I wouldnt recommend any of the other silicones, like the "high heat" red, although it might work. UC has another 50* + on HH red..

Inside the stove, if its seeing direct flame, youre into gasket/stove cement territory. I used water glass type adhesive to make a new donut gasket for the air tube under the baffle in my T6 and its held up well, but its not in "direct" flame, although its in a very hot part of the stove, directly under the baffle.

 

[BrotherBart]

I am always fascinated with the different temp ratings for silicone. Silicone vaporizes at 800F. No matter what you mix it with. If it goes "poof" the other stuff is standing there abandoned.

Door frames shuck enough heat that stove makers figured out that it is fine for gluing the door gasket. Englander used it on my 30 and that stove found 1,000 degrees stove top one night and the gasket just sat there and smiled at it. Been in there since 2006 and four cords a Winter.