Enlarging Casting Resin

HydroSpan 100, from Houston-based Industrial Polymers Corporation, is billed as “a 3 dimensional copy machine enlarging any shape or design in near perfect proportion and detail.” Shown uppermost, a Morgan silver dollar from 1896, enlarged via three generations of HydroSpan 100 casting to about the size of a salad plate. To use it, two components are mixed and poured into a conventional silicone mold. After curing for 24 hours, the resulting casting is soaked in water for a period of several days, swelling it uniformly to 160% of its original size. The enlarged casting can then be remolded and the process repeated as many times as necessary to achieve the desired final size. Industrial Polymers also manufactures a shrinking casting resin if you want to go down the rabbit hole, instead.