Where do you get sheet masonite?

Lowes, Home Depot and some local lumber yards carry 1/8 and 3/16 inch 4x8 foot sheets of the dark brown, tempered hardboard, also called masonite. Freeman Mfg. carries 1/4"(online). Another version is untempered hardboard. Art suppliers carry smaller sizes. Shower stall enclosures sheets using an 1/8 in. coated surface are available. Beware of store personnel who won't recognize the product names and need a detailed description.