[Polyform Products] A brand name for a plasticized Polyvinyl chloride based modeling compound. Sculpey is a polymer clay composed of PVC, plasticizers, coloring agents, and fillers. Original Sculpey comes in a variety of colors and feels like modeling clay but does not dry out until it is oven baked. Sculpey does not shrink when it is baked in the oven and does not crack, shatter, or break easily.
Sculpey contains about 15% di-(2-ethylhexyl) terephthalate (DOTP) plasticizer. Prior to 1991, it contained di-(2-ethylhexyl) phthalate (DEHP) which is now listed as a carcinogen.  The soft, uncured Sculpey should not be placed on painted or varnished surfaces as the plasticizer will dissolve these materials. Additionally, uncured Sculpey may be affected by solvent based paints. Sculpey instructions recommend baking at temperatures below 130C (275F). After baking, the material solidifies and can be sanded, drilled, carved, or painted. 
Synonyms and Related Terms
modeling clay; Sculpy (sp); polymer clay; oven-bake clay; oven hardening clay
Do not inhale fumes while baking. Overheating in the oven will result in blackening and release of irritating gases including hydrogen chloride vapor (polyvinyl chloride decomposes at 190°C/375°F).
- Hydrochloric acid vapors are a hazardous decomposition product.
- Incompatible with materials made of PVC (polyvinyl chloride) and polystyrene.
- Shelf life of a few years if stored in a cool, dry place, below 90°F and out of direct sunlight.
Deemed “Unsuitable” by the National History Museum of London.
Do not wash clay dust from sanding down the sink, as water treatment plants are not able to remove fine particles from wastewater.
Original Sculpey instructions are to bake at 275°F (130°C) for 15 minutes per ¼ in (6mm) thickness.  An oven thermometer is recommended. After baking, the material solidifies and can be sanded, drilled, carved, or painted. Do not heat above 175°C (350°F), allow to come in contact with open flame, or use with hot knife or wire. Do not use a microwave oven for baking. Do not over-bake or exceed recommended baking temperature or time.
The soft, uncured Sculpey should not be placed on painted or varnished surfaces as the plasticizer will dissolve these materials. Additionally, uncured Sculpey may be affected by solvent based paints. Do not place unbaked clay on furniture, flooring, plastic, carpeting, or fabric. Marble, lucite, granite, glass, ceramic tile, metal, aluminum foil, and parchment paper are all acceptable work surfaces. 
Forms and Sizes
Information from the Original Sculpey® Product Page:
- Colors: white, gray, granite, and terra cotta
- Package sizes: 1, 1.75, 3.75, 8, and 24lb
Resources and Citations
- Sculpey: [Website]
- Kaela Nurmi, contributed information, MWG group, 2020.