# Where to buy high temp sealant



## robsco (Dec 29, 2011)

Does anybody have a good source for high temp silicone or other type of sealant. Trying to seal joints in stove pipe. I have tried high temp copper rtv from advance auto, it dries up and flakes off after a few weeks. Can't seem to find anything with a higher temp rating.


----------



## Whitespider (Dec 29, 2011)

Ain't no silicone gonna' hold up to that kind's heat.
The best thing you're gonna' get for that is Furnace Cement or the cement used to glue the gaskets on wood stove doors.


----------



## OH_Varmntr (Dec 29, 2011)

I got some Wood Stove Sealer. Got it at Menards.

Good for 2000 degrees. I used it to seal up all my gaps and it had worked great so far.


----------



## logbutcher (Dec 29, 2011)

Unless your flue pipe is the thin gauge "black" stovepipe ( some pics show that here ) sold in hardware and big box stores there's no need to seal good pipe. If run the right way with male ends facing the stove, any slight opening in the flue will do nothing to spoil draft. Draft can be checked with a "draft meter" borrowed from any good HVAC tech. Engineered double ( e.g. Selkirk ) and triple wall flues have secure fastened joints. Movement of single wall piping will crack or deform any kind of sealing compound. Why bother ?

Gasket cement a.k.a. "water glass" is for gaskets on wood furnaces and stoves. It will not fill gaps or cover holes. If you really want to seal use a high temp ENGINE GASKET CEMENT or GASKET MAKER (mine is a lovely red :hmm3grin2orange

JMNSHEO


----------



## stihlaficionado (Dec 29, 2011)

MEECO Manufacturing Company, Inc.

try this company. I've used the furnace sealant w/ good results. Bought at Do It Best hardware, but available lots of places


----------



## mga (Dec 29, 2011)

lowes sells high temp mortar


----------



## 1project2many (Dec 29, 2011)

> use a high temp ENGINE GASKET CEMENT



Good for 600-800 deg F. As previously said, doesn't stand up to serious temps. I couldn't find anything that stayed flexible and worked at temps over 800 deg when I installed my chimney pipe. Pipe manufacturer specified 1200 deg sealant for flange at roof but didn't supply it and didn't list a source. 

Might end up with an epoxy that's NASA quality.


----------



## robsco (Dec 29, 2011)

Does the furnace cement or glue stay flexible. I am trying to seal single wall black pipe that is installed ahead of double wall stainless. Furnace is fan forced and does let some smoke escape at times.


----------



## robsco (Dec 30, 2011)

Somebody on here has to know of a sure fire way to seal stove pipe??? I'm sick of cleaning black dust off everything in garage daily. Please chime in if you have any ideas. Gonna look at stove sealant and high temp mortar today. Seems like both would get hard and crack though. Any thoughts on car header wrap? Will consider all ideas


----------



## 1project2many (Dec 30, 2011)

As I said, you're likely to end up with one of the high temp epoxies that are available. Header wrap isn't designed as a seal it's designed to retain heat. The heat retention speeds up natural oxidation of the headers and on something thin like a stovepipe it might cause rapid degradation. Muffler cement is used to fill gaps and cover seams in exhaust tubing. It doesn't stay flexible but if you coat one piece of pipe before installing it in the next it should cure and stay put.


----------



## Whitespider (Dec 30, 2011)

If you're cleaning black dust up every day than you've got something else wrong that you need to deal with first...


----------



## tooold (Dec 30, 2011)

Whitespider said:


> If you're cleaning black dust up every day than you've got something else wrong that you need to deal with first...



I agree, you don't have nearly enough draw for some reason.


----------



## robsco (Dec 30, 2011)

Bought furnace cement today. Says it makes metal to metal joints smoke and gas tight. Will bridge 1/8 inch gaps and good for 2000 degrees. Sounds perfect, have to wait and see. Smoke seems to puff out joints when i have a large fire and heavy flue draw. This makes door in front of fan flap and causes puffing. Most black dust actually comes from smoke exiting door when filling, this is a whole other problem i'm workng on. Who would have thought moving an owb into a garage would be so difficult.


----------



## 1project2many (Dec 31, 2011)

robsco said:


> Bought furnace cement today. Says it makes metal to metal joints smoke and gas tight. Will bridge 1/8 inch gaps and good for 2000 degrees. Sounds perfect, have to wait and see. Smoke seems to puff out joints when i have a large fire and heavy flue draw. This makes door in front of fan flap and causes puffing. Most black dust actually comes from smoke exiting door when filling, this is a whole other problem i'm workng on. Who would have thought moving an owb into a garage would be so difficult.



Just curious... if you leave an outside door open does anything change in regards to the smoking?


----------



## logbutcher (Dec 31, 2011)

*Problem is NOT Pipe Cracks*

Re-read the suggestions from previous post such as Whitespider ("Spidy") here.
IF your flue has good draft small cracks should not affect the draft or leak smoke. You have 'other' problems that inflexible furnace cement or any sealer will not solve. Metal pipe moves a lot.

Try:
1. Is the cap or top of the flue blocked -- dead birds, neighbor playing with you, creosote ?
2. Hot fires with dry splits and plenty of paper firestarter ( no banjo starters please like AV gas :hmm3grin2orange: ) ?
3. The "cracked door" makes sense IF the stove is older without good primary air control ---could be clogged or inoperative.
4. Is the "flue" too large for the stove e.g. stove specs 6" flue, butt you have it into a 12" square masonry chimney ?

How'd we do ? PM us for a bill.

Oh yeah: If the day is warm, damp with low barometric pressure, e.g. rain, a marginal flue will not draw well.


----------



## tooold (Dec 31, 2011)

quote "Smoke seems to puff out joints when i have a large fire and heavy flue draw"

I wonder if it has plenty of draw but is being choked down to to the point of needing air to burn. When it does get enough air to make combustion, it puffs. What happens when you open the inlet air some? Does it smooth out the combustion and burn without puffing?


----------



## robsco (Dec 31, 2011)

If i crack door to allow unlimited air intake puffing stops. Also if I close damper on outside of fan partially puffing will stop. Any ideas on stopping smoke while filling or checking fire?


----------



## zogger (Jan 1, 2012)

robsco said:


> If i crack door to allow unlimited air intake puffing stops. Also if I close damper on outside of fan partially puffing will stop. Any ideas on stopping smoke while filling or checking fire?



Taller stack? 

Although I think it is this: Is the room where the burner in real air tight, perhaps it can't quite get enough draft when the furnace door is opened? The air going into the burner has to come from some place, if it isn't sufficient, it will start to cause a vacuum on sudden high demand (door opened) then seek a pressure level and maybe poof back. 

All I can think of.


----------



## robsco (Jan 1, 2012)

when i said crack door and it stops puffing i was referring to stove door. Stove is in detached garage with a 18 x 8 garage door so i definitely don,t think it is sealed too tight. i think toold has it right, flue is trying to draw more than fan and damper will allow causing puffing under right conditions. still I need to seal joints in stove pipe


----------



## tooold (Jan 1, 2012)

It just made me think of the burning barrel we had when I was young. If the barrel was mostly empty and we had lots of fuel in it, it would do the puffing thing as air would once in a while make its way down to the bottom. After we torched a breathing hole at the bottom to let air in, no more puffing.


----------

