Cast core reinforcement

[mcfish]

As I have read about different refractory materials, it seems like many are fragile.  In the realm of concrete construction, various fibers are used to strengthen concrete.  In refractories, heat is the issue.  A prior thread mentioned basalt fibers, but comments seem to think carbon or fiberglass was better.  

The various websites I have reviewed all seem to agree that basalt fibers have a much higher working temperature than glass or carbon.  Basalt has working temps of 700 degrees C, glass less than half that.  Melting temps are much higher at 1450 C, or about 2600 F.  

Basalt can be purchased in a mesh format, continuous strands, or chopped fibers. Of course, most suppliers want to sell in larger quantities than we might want to buy. 

Am i way off base here, or is it just a cost issue and quantities?

[Donkey]

I've never felt the need to put fiber in the heat core part(s) of the stove.
In the bench and in the cob that surrounds the heater core, but not in the intense heat.
In those places, straw (rice is my favorite) is all you need.

[Vortex]

I put chicken wire in my casts to hold them together in the event of a crack.