I am curious if I could use a flu set mortar as the coating over the ceramic fiber (after rigidizer) or would this be similar to using a refractory cement, I have a local block company that sells "ALSEY Flue-Set" Non-Water Soluble Refractory Mortar-- Medium Duty, which has a service temp of 2700. I am attaching the product data sheet, after this I would apply either the ceramic coating
Flue-set_NWS_mortar.pdf