Plaster Ornamentation & Millwork
Plaster is an age-old casting media used today for casting statuary, home decor items (e.g., lamps, wall plaques) as well as ornamental moldings and decorative millwork.
Polytek® manufactures two-component, room temperature curing polyurethane and silicone mold materials that are used widely in the plaster casting industry to create highly detailed plaster parts.
Plaster can be cast repeatedly into either polyurethane or silicone molds without release agents. The primary differences between polyurethanes and silicones are the cost (silicones are more expensive than polyurethane) and the range of hardness available within the product lines. For highly detailed and delicate castings, silicone rubbers may be necessary as they are available in softer and more flexible options compared to polyurethanes.
TIP: To reduce surface air bubbles on plaster castings made in Polytek® rubber molds, consider using Pol-Ease® Mold Rinse. Dip or spray the mold with one part Pol-Ease® Mold Rinse diluted with ten parts water. Molds should be wet when plaster is poured.
Review popular product options below:
Polytek® polyurethane rubbers are an economical (less expensive than silicone rubbers) and long-lasting mold option for plaster casting. Release agent is not necessary when casting plaster into these molds.
Select an option below for additional product details and buying information or browse all polyurethane mold rubbers:
POPULAR OPTIONS
| Product | Description |
|---|---|
This rubber is the industry standard in plaster casting. It is a medium-soft polyurethane rubber with a simple 1A:1B mix ratio. This is a pourable rubber, but can be thickened with PolyFiber II or Fumed Silica to make brush-on molds when desired. Thin, brush-on molds require a supportive mold shell - review Mold Shell Materials below. |
|
A self-thickening, medium-hardness polyurethane rubber with an easy 1A:1B mix ratio. Ideal for larger original models or models that are located on vertical or overhead surfaces. A spray version is also available. Thin, brush-on molds require a supportive mold shell - review Mold Shell Materials below. |
Platinum-cured (PlatSil®) and tin-cured (TinSil®) silicone rubbers work very well for plaster casting and may be required when working with very delicate castings.
The silicone mold rubbers listed below are pourable, but can be easily thickened for brush-on application when desired. PlatSil® silicones can be thickened with PlatThix Liquid Thickener for brush-on application and TinSil® silicones can be thickened with TinThix Liquid Thickener.
Select an option below for additional product details and buying information or browse all silicone mold rubbers:
POPULAR OPTIONS
| Product | Description |
|---|---|
A super-soft, platinum-cured silicone rubber with an easy 1A:1B mix ratio; demolds in 30 minutes. Use for highly detailed and delicate castings. |
|
A medium hardness, platinum-cured silicone rubber with an easy 1A:1B mix ratio; demolds in 4 to 5 hours. |
|
A medium-hard, platinum-cured silicone rubber with a 1A:10B mix ratio; measure with a digital scale. Use for long castings with minimal undercuts that require stability. Demolds in 16 hours. |
|
A tin-cured silicone rubber with a 1A:10B mix ratio; measure with a digital scale. Tin-cured silicones are slightly less expensive than platinum-cured silicones; however, they have a shorter library life and shrink slightly on cure. |
NOTE ON CURE INHIBITION: Sulfur/tin/amine-contaminated materials and tools will cause cure inhibition in platinum-cured silicone rubbers (e.g., PlatSil® 73-25), which means that the rubber that is in contact with the contaminated surface will remain gummy or uncured. Make sure to test cure the rubber on your surface before full-scale application. Use a polyurethane or tin-cured silicone rubber if you know that you’ll be working with any of these inhibitors.
Thin, brush-on molds require a supportive mold shell. Mold shells can be made with a number of materials, including plaster, polyester resin and fiberglass and thickened polyurethane plastic. Polytek® offers strong, fast-setting polyurethane plastics that are widely used in mold shell construction.
Select an option below for additional product details:
POPULAR OPTIONS
| Product | Description |
|---|---|
A polyurethane casting plastic with a 5-minute working time. Thicken with PolyFiber II for brush-on application. |
|
A polyurethane casting plastic with slightly longer working time (10 minutes) than Poly 1512X. Thicken with PolyFiber II for brush-on application. |
Video Tutorials
Image Gallery
