Hydrostone Plaster for Scenery, Dioramas, Dentistry and Mold Casting and Great for Model Railroads & Gaming (5 Pound) Hydrostone Plaster for Scenery Dioramas and Casting, Creates Super Hard Castings With Great Detail Quick setting, lightweight white plaster in water resistant bag. Ideal for patterns, figurines, commercial casts, and sculpture. It is not for making outer or mother molds, and it is not recommended for outdoor use. Full strength Hydrostone gypsum plaster, not cut with cheap plaster fillers Designed for strength and casting detail. Hydrostone is 40% to 50% harder than casting plaster and works much like plaster in mixing, pouring, and setting. Accepts liquid or crystal pigment colors and stains