Design your model, choose your Modroc, add water and away you go!. Modroc, Modrock or POP Roc as its sometimes referred to, is cotton gauze, medical plaster bandages that are are impregnated with quick-drying Plaster of Paris and used for modelling, casting, and crafting. Ideal for the construction of 3D models by application to an inflexible frame, for use with some of our metal modelling items such as wire netting. Large continuous bandages, ideal for larger scale projects. Each pack gives a coverage of 12m². Each bandage is 150mm wide. Approx. 80m long.