High Heat Silicone Sealant

[fire_N_ice]

I was in the fireplace store the other day asking about this sealant. The fireplace is gapped where the marble meets the frame. There was some sealant in there and it looks like it has pulled away from the edges. Is there a high heat sealant that exists in the 700-1000 degree range in white or black without going with a gasket sealer from the automotive store?
1 fireplace store said it exists but they don't carry it, however another said it does not.

HD and Lowes have 500 degree sealant .

TIA for any replys!!

 

[BrotherBart]

Furnace cement is good to a couple of thousand degrees but it is messy and will turn grey after getting hot.

Shoot a picture of where you are talking about putting this stuff. Nothing at the edges of that fireplace should be getting anywhere near 700 degrees.

 

[fire_N_ice]

will do....... Pics edited in, just tilt your head .

 

[BrotherBart]

Got a crick in my neck but that looks like a large gap. ACE Hardware will sell you the 600 degree RTV silicone sealant that should handle temps at those spots fine. It is with their wood stove stuff. The stuff is messy. Another thing you could put in there is stove window gasket. It is flat fiberglass and heat ain't gonna affect it lately.

On the silicone subject, I am the lone dissenter in the world that says there ain't no difference between the eight buck a tube 600 degree stuff and the $3.99 regular silicone caulk. 100% silicone caulk is 100% silicone caulk. I think the six hundred degree stuff just had red or black dye added. All silicone is going to vaporize around 800 degrees but the blocking plate sitting eight inches above the top of my heating monster wood stove is held up with plain old silicone caulk and it hasn't moved lately. The top plate on the chimney liners are sealed with it too. On sale for a buck ninety-nine a tube.

The factory installed the door gasket in my Englander with the 600 degree stuff and it is subjected to the radiant heat of 1,200 degree fires in that firebox an inch away from it so I think it will do it for you just fine.

 

[Nativedancer]

I have a Whitfield Advantage II, and one day the solid curved front glass broke. The cost is $495 to replace it. I was going to try to use a high temperature Sealant on the glass. I wondered about exhaust sealant, but not sure how high the temperature can get on a catalytic converter, and I am worried about breakdown at 800 degrees. In my research I have found the glass to be a plexiglass. I put an oven thermometer and it came to 800 degrees running at full blast, with the air reduced down, so that is my possible maximum. The broken front glass reduces the efficiency of the wood pellet stove and right now being unemployed I really need that. Here is a picture of the fireplace. Any help or suggestions I would be grateful for. J

UPDATE!
UPDATE:I think I may have found something for high temperature sealant: Versuchem Muffler and Exhaust Sealant. It goes to 1000 degrees, 1500 degrees intermittent and about $4. AND there is (this is the most recommended one) Inferno Metal Repair goes to 2000 degrees, and Is available at Autozone parts stores, part number 30671, and it is $5.99.It is not tested on glass, but it does not expand.