“GRG” (Glass Reinforced Gypsum) is a molded product with a high strength to weight ratio that is used in construction to replace the disappearing art of plaster. In the past, “Master Plasterers” would reproduce stunning run-in-place architectural columns, domes, vaults, arches, cornices, etc… Today, there are very few “Masters” left. “GRG” produces these results in a premolded, light weight, time tested composite for far less the cost. It has been used on probably millions of projects all over the world to continue the “charm” of both traditional or classical architecture and to create the free flowing forms of modern design.
“GRG” is a multi-layered composite using only two basic raw materials: continuous strand fiberglass mats in a matrix of high density “alpha” gypsum cement plaster. A gypsum surface coat is applied to a mold (the “negative” of the shape required) and further alternating layers of fiberglass and gypsum are hand laminated until the desired thickness is achieved, typically a nominal 1/4”. The hand “lay-up” method allows consistent control of the shell thickness as well as the incorporation of embedded items for stiffness, strength, attachment and/or hanging. Once the “GRG” has set, the part will maintain it’s shape and it is removed from the mold, stored to prevent distortion, finished and inspected, and is ready to ship. Daily production is a function of environmental factors, piece size and profile and the cure rate of the gypsum; usually allowing a minimum of four to a maximum of six pieces per day from the mold. Large projects may require that multiple molds be made of the same shape to increase daily yield.
Multiple layers of continuous strand fiberglass mat cast into a matrix of high density gypsum cement plaster. Materials are polymer free. Shell thickness is a function of the number of fiberglass layers and the type of fiberglass used. Thicker laminates as req’d.
Plywood and/or metal at attachment/hanging flanges for fastener support.
Foam and/or wood “ribs” back-laminated into “field” areas of large profile/flat shaped parts for additional rigidity/flatness.