There is a lot of conflicting information about polymer out there. It’s hard to know what’s true and what’s not. Much is passed from clayer to clayer. I made a list of some of the biggest tips and advice I hear and the best truth I could find, not just “what everyone knows”
1. Don’t eat it. This is a big duh but actually this rule sums up how safe it is. You can do just about anything to it, with it but just don’t eat it. It’s not toxic but it’s still not good to eat.
2.. You need a dedicated oven. This one is false. The good news is it is safe to use your own oven based on this study from Duke University. You can use a dedicated oven if you want but if you want to spare the expense, your home oven is fine to use. An oven thermometer is good thing to have but I discovered my new oven with digital thermometer is super accurate. If the fumes bother you, some people might not even notice, you can use a covered dish or I discovered plastic turkey bags work really well to keep the fumes in. The fumes are non-toxic unless you burn the clay and this won’t happen until 300F for most clays.
3. Any tools or trays you use must be dedicated to clay only. This is definitely true. Kitchen tools work well for polymer clay - like garlic presses, rolling pins, graters and more. If you use it for clay, make it clay only. You might be able to fully clean nonporous smooth tools but don’t tempt fate here. If it is porous in anyway like wood, it’s all clay or not at all.
4. Don’t use it to make dishes or anything to eat off of. True, polymer clay is porous and even if you glaze it, you can’t keep the bacteria out and it is not safe for eating off of either.
5. Don’t burn it. This is crucial, this is the only time the fumes are toxic – toxic in that they will irritate you but there is no lasting issue. Different clays bake at different temperatures so check the package. Fimo will bake at 260 F, Kato needs to be 300F to fully cure.
6. Don’t mix clays. As far as baking goes, if you mixing clays – either mixing colors or using different types in one piece there shouldn’t be any problems. Most clays cure near 275F so mixing them isn’t an issue. I just wouldn’t use clays at the 2 extremes (Fimo 260 and Kato at 300) Either one can be mixed with Premo, Sculpey, Cernit etc that cure at 275. I usually use a temperature in the middle to bake it at.
7. Beware of phthalates in clay. Dioctyl phthalate was used as a plasticizer. Due to possible health risks, it was banned. The phthalates used in polymer clay today are monitored under all of the hazardous materials testing mentioned above. One more worry gone.
These are just a few of tips and hints about polymer clay clarified. I’ve also found there were no absolutes. Cynthia Tinapple of PolymerClayDaily has projects when she uses temperatures of 400F (for 5 minutes) and others were she just uses a heat gun. I personally used my own oven for years until I went to clay guilds and was told this was a big no-no and I need to buy an dedicated oven. I decided to risk it since I had been using my own for so long; I was glad when I found studies proved I wasn’t poisoning my family.
There are lots of do’s and don’ts out there for polymer clay. Some are true, some are just anecdotal. What are some rules you’ve about polymer clay?