Repointing inside of chimney

[basil1]

I am about to install a woodburning stove but before I put in the steel register plate, I wanted to repoint some of the brickwork as the original mortar has turned to sand and needs scraping out.

I have been told that I can't use normal mortar as the heat generated will cause it to 'blow' and therefore need to do it with a special type of mortar.

Does anyone know what the mixture is or where I can get it from?

Thanks.

 

[NickStone]

Pyruma is a fire cement, but I'm not sure if it's suitable for pointing brickwork. I had a cast iron woodburning stove in a brick fireplace for 12 years and I used ordinary pointing mix at back and sides. It never blew.