Sculpture, Foundry & Figurines
Liquid mold rubbers and casting plastics are used extensively in the reproduction of figurative sculpture. Original pieces are most often sculpted/carved from clay, wax or wood and a rubber mold is poured, brushed or sprayed onto this original to capture all detail and to allow flexible demolding from undercuts and negative draft.
A variety of casting materials can be poured directly into these rubber molds, including wax, plastics, plaster and concrete. Casting plastics can be a very versatile medium for the reproduction of sculpture as they readily accept fillers (e.g., bronze powder for cold cast bronze) and dyes that help to produce unique looks. Depending on the mold material selected, a release agent may or may not be required for the casting process.
For foundry applications, this rubber mold is one step in the lost wax process that ultimately creates a mold capable of accepting the heat of molten metals and alloys (e.g., bronze).
Review popular mold making and casting materials below:
Polytek® polyurethane mold rubbers are most often used for casting wax, plaster and concrete. Release agent is generally not required when casting wax and plaster, but is needed when casting concrete. Limited resin casting can also be done with the appropriate release agent (e.g., Pol-Ease® 2300 Release Agent). Polyurethane molds are an economical and long-lasting for sculpture reproduction.
Select an option below for additional product details and buying information or browse all polyurethane mold rubbers:
POPULAR OPTIONS
| Product | Description |
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This mold rubber is the industry standard for sculpture and foundry applications. This pourable rubber can easily be thickened with PolyFiber II for Fumed Silica for brush-on application when desired. |
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This mold rubber is a transparent amber version of Poly 74-30. It is popular for small sculpture reproduction that requires wax injection molding. Because the molds are transparent, it is easier to see thorough injection of the wax and can also be helpful when cured molds need to be cut. |
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This is a self-thickening, sprayable mold rubber that is most often used for reproducing monumental sculpture. It can be dispensed with a PlasPak Spray Gun for small applications or industrial spray equipment for larger applications. |
Polytek® silicone mold rubbers can also be used for wax, plaster and concrete casting, but are most beneficial for high volume resin or foam casting. Release agents are generally not needed for casting any of these materials, which is why they are sometimes preferred over polyurethanes. For resin sculptures that need to be painted after casting, silicone mold rubbers are recommended. Tin-cured (TinSil®) and platinum-cured (PlatSil®) silicone options are both available.
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 medium hardness, tin-cured silicone rubber with a 1A:10B mix ratio (digital scale required for measuring) and 24-hour demold time. Can easily be thickened with TinThix Liquid Thickener for brush-on application. TinSil® silicones have a shorter library life compared to PlatSil® rubbers and also shrink slightly (~1%) on cure. |
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A medium hardness, platinum-cured silicone rubber with a 1A:1B mix ratio and fast demold time of 4 to 5 hours. Can be easily thickened with PlatThix Liquid Thickener for brush-on application. |
Sulfur in your clay?
Sulfur-containing clay and other 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 clay model or 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.
The NaturForm Series offers high-performing, natural molding latex rubbers that are often used to make molds for casting plaster and concrete statuary and limited casting with some resins. NaturForm products offer excellent tear strength and elongation properties and are available in 60-64% solid content options and a high solids option (70-74%). NaturForm 60-R has an internal release agent that assists in the release of casting materials, like concrete.
Since individual coats of latex must dry before further coats are applied, mold making may take days or longer to complete properly. For one-day brushed or sprayed molds, consider using Polygel®35 Brush-On rubber (16 hour demold time) - featured in the Polyurethane Mold Rubber section above.
Select a NaturForm Latex to learn more:
| PRODUCT | PERCENT SOLIDS | COLOR | VISCOSITY |
|---|---|---|---|
| NaturForm 60 | 60-64% | White | 8.15 ± 0.1 lb/gal |
| NaturForm 60-R (with internal mold release) | 60-64% | Blue | 8.15 ± 0.1 lb/gal |
| NaturForm 74 | 70-74% | White | 8.1 ± 0.1 lb/gal |
Thin, brush-on or spray-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 and buying information:
POPULAR OPTIONS
| Product | Description |
|---|---|
A polyurethane casting plastic with a 5-minute working time. Thicken with PolyFiber II for brush-on application. |
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A polyurethane casting plastic with slightly longer working time (10 minutes) than Poly 1512X. Thicken with PolyFiber II for brush-on application. |
Use Polytek® polyurethane casting resins to create unique sculptures of varying looks and feel.
Select an option below for additional product details and buying information or browse all polyurethane casting plastics.
POPULAR OPTIONS
| Product | Description |
|---|---|
A fast-setting, low-viscosity white plastic that is often mixed with Bronze Powder and PolyColor Dye to make cold cast bronze sculptures. This plastic has a simple 1A:1B mix ratio by volume and a fast demold time of 15 to 30 minutes. |
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A translucent, amber version of EasyFlo 60. Color with PolyColor Dyes for colored, translucent castings. |
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A fast-setting, low-viscosity white plastic for slush-casting or rotational casting to produce lightweight, hollow castings. |
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Water-clear plastics that can be used as is or tinted with PolyColor Dyes. |
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