HARD-CORE BLUE™ casting material and solution are sold in pre-measured amounts required for mixing. HARD-CORE BLUE™ is an all-purpose, gypsum-based casting material that offers Herculean strength, accurate reproductions, simplicity of use and long term economy. It is a “dental stone” casting material proven to be the most efficient and practical method for casting tire and footprint impressions. Its superior strength eliminates the need for reinforcement. Typical casts are 1/2" to 3/4" thick (compared with several inches thick using plaster), and offer some amazing properties. It has been stored for months on end in the trunk of a vehicle with no apparent loss of efficiency—from subfreezing to temperatures in excess of 100° F (38° C). It sets up in a shorter time and has only a minor exothermic reaction. Only larger impressions require damming or flow restriction.