# High temperature masonry adhesive?



## xhibit4 (Feb 22, 2010)

Built a fire pit/place out of stone on property, capped with Flagstone, rear wall pieces adhered fine but sides and front did not. Removed the loose pieces, substrate is perfectly level with no holes or indentations. Do not want to remove mortar and start over, just want to lay a bead of something that will withstand the *temperature* and *adhere* to both surfaces. Quikcrete makes a fireplace mortar in a caulk tube but was told by Manufacturer it was not for my application. Any suggestions?


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## NJ Brickie (Jan 31, 2009)

Cultured stone is not meant to be installed in a fire pit. You need to start over completely. Not just the stones that fell off.


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## bytor (Jan 23, 2010)

Years ago I contacted the technical department of one of the 'thinset' manufacturers . They assured me that their product would be acceptable in a high heat environment (the un-modified variety).... never did try it out though...


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## xhibit4 (Feb 22, 2010)

NJ Brickie said:


> Cultured stone is not meant to be installed in a fire pit. You need to start over completely. Not just the stones that fell off.


 The firepit is 10' w X 4' L X 4' high sitting on a 10 X 4 slab, bottom is lined with dry fitted half thickness firebrick, there has been no problems with the fire ( and they are monster fires) hitting the back wall attached Flagstone nor was there any issue with the Flagstone that needs to be re-attached. It looks like a big couch so the heat is not concentrated.


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## xhibit4 (Feb 22, 2010)

bytor said:


> Years ago I contacted the technical department of one of the 'thinset' manufacturers . They assured me that their product would be acceptable in a high heat environment (the un-modified variety).... never did try it out though...


 Thanks,doing a bathroom with Schluter system membrane so I have Lacrete Megabond, have to give them a call.


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## Tscarborough (Feb 25, 2006)

I have used several brands and types of thinset in high temp applications (>500 degrees) and they all failed. There are several types of refractory cement available, any of the dry types will work. Insulstick is probably the best for your application.

You can make your own, 1/1/1/3, portland/lime/fireclay/very fine silica sand.


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