USG Casting Fireplace Surrounds - Manual (Page 10)

To get going, start simply and think about this four-step process:
Mold Making The actual fabrication process begins with making the mold. Mold quality will directly affect the quality of the fin-
ished piece, so select a mold maker whose skills complement your desired market positioning. Many fireplace sur-
round fabricators have in-house expertise in mold-making.
Raw Material The only gypsum cement products that USG endorses for this application are H YDROCAL ® FGR, E NDURACAST ™
Selection Gypsum Matrix, or other custom-formulated alpha gypsum cements manufactured by USG for fireplace surround
production. (See Raw Materials.) Your USG sales representative will help you select the material to match your
plans. You will need to have fiber reinforcement such as glass fiber or glass matting, mold release materials, a
clean water source, safety glasses, dust masks and gloves. Keep all gypsum cements and aggregates dry and
above freezing temperatures before use.
Fabrication Method Start by using a hand-layup method of filling the molds to get to know the gypsum cement product’s setting time,
expansion, pigmentation and aggregation capabilities, and how easy it is to work with. In this way you will also gain
experience with how easily the cast parts remove from the mold, the quality of the mold details, and how easily the
mold is cleaned and serviced. Properly supporting the cast surround immediately after removal from the mold is
also important, and there are various methods to ensure dimensional stability during drying. The time required
to fully dry the parts is also important, due to its effect on daily output. A surround is not ready to finish and install
until it is fully dried of all free moisture.
Waste Management Preparations for disposal of wooden pallets, paper bags, and wash-out and waste water should be part of the early
stages of business planning, along with dust-control procedures. Gypsum cements are environmentally friendly,
but cleaning molds and mixing the gypsum cement products produces water and gypsum waste that is messy if
not properly managed. Properly designed shops take waste-control procedures into account in the production
flow process, and good planning will minimize waste from the operation.
Production
Getting Started
10 Casting Fireplace Surrounds