Polymer clay 'cures' or hardens in the oven, by polymerizing. I was never good at science, but basically it means the plastic molecules in the clay need a heat reaction to solidify.
I recently rediscovered polymer clay when I came across an old shoebox full of old Sculpey. Even though the clay was at least fifteen years old, it was still usable. It just took a lot of kneading to get it back into shape, but it has baked up just fine. If the clay is very crumbly, I have heard it is no longer good, but how long that would take I don't know.
- Be immaculately clean- Polymer clay picks up every piece of dust and pet hair it can find. I don't have a cat, but have found the occasional stray cat hair in my clay. Make sure to wear clothes that don't produce lint, and clean everything (including your hands) really well in between colors.
- Follow directions- To 'cure', or harden, polymer clay must be baked in an oven or toaster oven. Do not use a microwave. Follow the temperatures and baking times on the package of clay.
- Removing forensic evidence- Before baking, you can try and smooth out fingerprints using the edge of your finger . Or after baking, you can use a very fine grit sandpaper or a nail buffer to smooth out fingerprints.
- Conserving clay- for large projects, balls of crumpled aluminum foil can be used as a base. You build up clay over the foil, instead of using as much clay.
- Metal and glass *before*, plastic *after*- you can bake metal and glass right in the clay, but plastic will melt in the oven and must be attached later. E6000 glue works well to glue plastic to baked polymer clay. If you're not sure if something will melt, best to attach it after baking and cooling.
- To Poly Clay or not to Poly Clay- polymer clay should not be exposed to open flames and is not food safe. Do not use it for an ashtray or a drinking glass. However, you can improvise. Cover the underside of a glass ashtray (the part under that touches the table, not the cigarettes), and you can safely use it. Polymer clay works really well for sculpture, magnets, Christmas ornaments, jewelry, miniature making, and accents for other crafts like scrapbooking.
- White or Multicolored- There are large blocks of plain white polymer clay, and smaller blocks of colored clay. There are pros and cons to each option. The plain white is cheaper in the larger size, and white is a commonly used color for mixing. Plus, you can paint the polymer clay once it's been baked and cooled, by using acrylic paint. The colored clays are the only way to go if you are making clay canes, since once the cane is cut to reveal a design, the color is necessary. If you make very small creations, painting them can be a pain. The basic colors you will need are a red, yellow, blue, white and black because you can mix any colors using those five. Colored clays also come in glow-in-the-dark, pearl, glitter, metallic, neon, and pastel colors.
- Glazing- If you want to add a glaze coating, only use one made to be used on Polymer Clay. Again, ONLY use a poly clay glaze on poly clay. I have tried clear nail polish and floor polyurethane, and both times my projects went horribly wrong. The nail polish melted the top layer of clay, and years later, its still gooey and gross. The floor coating turned this awful tobacco-stained brown and flaked off. Save yourself frustration and buy the good stuff.