I had my VC Vigilant wood burning stove since 1982 and am taking it apart the rebuilding it for the 3rd time now. The stove originally came with a small bucket of refractory cement, but i have not be able to find that same product since the firs rebuild about 30 years ago. Can it be purchased or will I have to mix up my own concoction to fill in the bottom of the stove. The re-build manual says to use sand or ashes, which I have done but refractory cement would be much better and easier to clean out ashes. Any advice or recipe for a mix would be appreciated.