Some more ideas: Scenic Express -- http://www.sceneryexpress.com/products.asp?dept=1062 -- has it in their "terrain building" section.
http://plaster.com/ offers it in plastic tubs (great convenience!) Outside model railroading, Hydrocal is used by foundries (when I lived in Dayton, I bought mine at a place called Fenton Foundry Supply) and by sculptors (when I lived in Portland, I bought it at a place that sold all sorts of moulding supplies such as bulk wax for candles that are used by artists.) The US Gypsum website has a where-to-buy dealer page. -- http://www.usg.com/where-to-buy.html. Lee Rainey
