I never thought much about the craft supply material, sculpey until I found out that a lot of the serious dinosaur sculptors used it. I tried it out when I was working on the Torosaurus sculpture and found that it was a very good material to sculpt muscles (on a small scale model). You can pull it and shape it in such a way that you can get very realistic looking forms mimicking the shapes of muscles tapering into tendons. Once baked, you can add more, sand it, carve it. It is wonderfully flexible, a perfect additive and subtractive sculpture material.
I put it away for three or four years and now I’ve decided to pull it out to sculpt the legs of the insects. Surprisingly, the old sculpey was still workable. I am able to rough out the shapes quickly, bake them, sand them, add more sculpey, sand more. In a day, I can get one or two fairly complicated legs knocked out. I have been using wax to finish off the joints where the final detail is more complicated. I found that wax and sculpey works very well. The wax smooths seamlessly with the sculpey. From these, I am making silicone molds to be able to cast them in their final form in translucent 5 minute epoxy.
Then since I had heard some mention that sculpey is not as benign as we would all like to believe, I googled “sculpey health hazards” and the US Pirg site came up with an article titled:
Hidden Hazards: Health Impacts of Toxins in Polymer Clays
The article looks to be very well researched and they point to several chemicals used that give cause for concern (especially with my kids using it) they write:
“these clays contain polyvinyl chloride (PVC) mixed with phthalate (pronounced tha-late) plasticizers. While the phthalate plasticizers make the clay soft and workable, they are also associated with potential health risks. Phthalates as a class of chemicals have been implicated in birth defects, reproductive problems, nerve system damage and other negative health effects.”
They also write that when sculpey is overcooked, it breaks down the PVC and releases poisonous hydrochloric acid gas. they also say that the phthalates are taken into the body through contact with skin. They recommend wearing gloves to work with it and ventilating the area where the baking occurs.
This brings me to a point I arrive at often in my line of work. What kinds of precautions should I take and what do I actually do. I take great care around epoxies. there is an epoxy putty that I used for years without gloves and then I found out I was absorbing it through my skin. I started wearing gloves. Urethane foam is another one I use only in a spray hood. Spray paint, polyester resin all fit into the spray hood category. If I do what is recommended, I would bring all my sculpey work to the museum (I am working at home in the evenings on the legs) and wear gloves. I will try working with gloves, but for now I am going to continue to bake at home.