Refractory mortars

[MikeD55]

Agreed. I’m don’t see anything that says it’s burnout fibers. I’d like to assume the fibers are there for crack prevention as this is what they seem to be touting BUT always good to confirm.

[david s]

The primary function of the really fine polypropylene fibres is not for strength enhancement, but for shrinkage crack resistance for standard concrete slabs. They also have the property of a low melting point which is exploited for refractory purposes, so I’m pretty sure that’s what they’ll be in the Haft 1000 product.
There aren’t any fibres that I know of apart from stainless needles that will withstand 1000C and you wouldn’t be putting those in a mortar.

[MikeD55]

Ok good to know. I will inquire. It would seem silly to put a fiber that cannot tolerate the heat since it’s being used in Masonry Heaters and brick ovens.

[david s]

No, shrinkage cracks in mortar or concrete occur when the material is setting, not when it is being fired.

[MikeD55]

Good point. I’m hoping that their mention of 1-60mm joints and shrink free/crack free holds true….