POLYTEK 74-20

Poly 74-20 liquid polyurethane rubber is designed for making flexible, high-performance, high-strength molds that are particularly well-suited for casting concrete (veneer stone, architectural cast stone elements, concrete countertops, etc). Release agents are often not needed when casting concrete in Poly 74-20 molds.These molds are also often used for casting materials such as plaster (for millwork, home décor, etc.), wax (candles & lost wax varieties) and resins (polyurethane, polyester, epoxy – with proper release agents). High tear and low viscosity make it especially easy to use.Poly 74-20 liquid rubber is an excellent multi-purpose, economical mold material that will provide long mold life, durability and consistent performance under high volume casting applications. This rubber can be poured as supplied or thickened with Poly Fiber II or Fumed Silica for brushing.

CALCULATION:
Determine volume of the
containment area:
(L” x W” x H”) = ________ in³
Determine volume of the model:
(L” x W” x H”) = ________ in³
Subtract the volume of the
model from the volume of the
containment area:
_________in³ - ________in³ =
____________in³
Divide the result by 27 in³/lb.
(the specific volume of most Poly Liquid Rubber) to determine
how many pounds of Poly
Liquid Rubber are needed:
_________in³ ÷ 27 in³/lb. =
_________ lb. of Poly rubber