http://www.sculpturesupply.com/list.php?sf=category&vl=casting+materials maybe not? I thought they carried the sand as well as high temperature silicone
industrial supplier in Ontario, similar to the one in Alberta so they should sell in smaller bales or drums http://smelko.com/site/?page_id=73
Yes and there is a larger supplier in southern Ontario, found it http://www.psh.ca/index.php?query=fireclay
I don't know what your casting but I tried The play sand and kitty litter recipe off the net for my first grinder drive pulley and it worked. The play sand is a little coarse though. So if your casting guards or pommels it might be too rough. Frank