Polymer Clay: 7 Basic Curing Tips

Polymer clay is a wonderful crafting medium to work with. Although some techniques are difficult to master, and some processes can be tedious, the incredible variety of possibilities makes polymer clay one of the most versatile mediums available.

Curing polymer clay can be one of the more difficult processes to master. It seems like it should be easy, just pop it in the oven for a few minutes, and it’s done. I only wish it were that easy.

Here are some tips to making curing your polymer clay a little easier.

Tip #1 Use an oven thermometer. If you don’t have a thermometer, get one. If your temperature isn’t accurate, your clay won’t cure correctly. Or it could burn. Polymer clay can even catch on fire if heated at too high of a temperature. Many oven have heat peaks, or are otherwise inaccurate. Figure out if your oven is, and adjust the temperature accordingly.

Tip #2 Don’t preheat your oven. Put the uncured piece in the oven, turn it on to the correct temperature, and THEN, when the oven reaches the correct curing temperature, start the official timing.

Tip #3 Don’t take the clay immediately out of the oven. When the timer goes off, immediately turn the oven off, open the oven door all the way, and let it cool off slowly for another 15 minutes.

Tip #4 Wrap any thin pieces of your clay in cotton batting, or tent with aluminum foil. Or both. Any little tiny protrusions or pieces run the risk of discoloration or burning.

Tip #5 Don’t place pieces meant to be cured in a glass dish to cure it without some layer of protection. The parts touching the glass will get shiny. You can use a glass dish as long as the piece doesn’t touch. Line it with foil. You can also use foil to hold pieces of clay in position for curing.

Tip #6 Most polymer clays are cured at 275 degrees for 15 to 29 minutes, for each quarter inch of thickness. Always stick to this rule unless the directions on the package says different. If you cook it at too low of a temperature, the middle might not cure properly, and the finished piece can develop cracks, sometimes years down the road. Too hot, and you could end up burning your clay, and maybe your house down with it. 275 degrees, ok? Burning or smoking polymer clay is toxic! Turn off the oven and air out your house immediately if you smell smoke or a strong odor.

Tip #7 If you bake a lot of polymer clay, get a separate oven just for this purpose. Supposedly polymer clay isn’t toxic at the recommended curing temperature, but, well, you never know, do you? Look at yard sales or second hand stores for a cheap one.