Refractory Mortar Poll

[david s]

Potters who want to reduce the shrinkage of a clay body add grog (crushed fired clay) which will not shrink. This in turn will reduce the shrinkage of the body because of the proportion of a non shrinking material. Sand would do the same, but for the potter not a good material because the sand will melt at higher temps (1000 C+)

[Glosta]

I am using Heat Stop 50 dry mix. It worked fine in fireplace, is waterproof and sets up quicker than I can work. Heat Stop 50 is $50.00 per 50 lb bag at masonary suppliers is MASS. Glosta

[lwalper]

I've been using the non-aluminate homebrew. It seems to work well - at least in the construction phase. It will be interesting to see how it responds to heat??

BTW, there is very little demand in this area for fireclay. My local materials source purchased a pallet of fireclay a couple of years ago for one job, sold two bags of the stuff, and there the rest of it sits. Mine is the first purchase of this particular item in the past two years. I wonder why the local brick masons don't use it in fireplace builds?—or maybe there are not that many fireplaces being installed? I seem to see chimneys going up. Hmmm . . .??

[WoodchuckDad]

Heatstop 50. My reasons are simple. I am anal retentive as all heck. I would constantly be second guessing myself for using a home brew. I just open the bag, scoop it into a bucket and mix it up. And while it is expensive, running down the different ingredients and mixing them together and figuring out how to store them so I have them ready when I need them takes time. And time is the one thing I have less of than anything else.