Sunday, June 30, 2013

Experiment; Over-baking polymer clay?

Experiment: Over-baking your polymer clay?

Ever since I bought that 'efcolor enamel' mini stove you've heard me talking about a few times, I've been wanting to make this experiment; What will happen if you over-bake your clay?...
You see, the efcolor stove gets really hot and if you bake any clay in there, it's very close to the surface (hottest place). I usually just use it for baking a master before making a mold, making clay plates etc.. But I noticed that the pieces that have been baked in there were pretty much unbreakable (extremely flexible). I'm not going to take a guess on the exact science of this ;) But I thought that the same effect might be possible to achieve with a regular oven, if you were to bake the clay for longer.
On the packages of clay I have, they tell you a temperature and that they clay should be baked for 15-30 minutes. Obviously I've always thought that the 30 minute mark would be somewhere around the 'max' for how long you should bake your creations. Apparently it's not - I was working on a new doll and was going to use the oven anyways, so I took a piece of the clay mix I used for the doll, rolled it into a snake and put it in the oven for an hour... Yes! an hour! haha.
I didn't cover it with tin foil or anything else, I just put it on the baking tray and into the oven. Besides the fact that it had a slightly different smell when I opened the oven (not any major difference) it looked fine. The color hadn't changed, and... it was extremely flexeble - now, I haven't tried wiggling it back and forth for multiple minutes, but I've bent the piece 5-10 times creating a narrow u-shape (from that straight snake) and it didn't show any sign of cracking! it just went slowly back to being a straight snake of baked clay!
I've tried with some more pieces of clay and even though some of them became slightly darker in color (probably depends on the brand), none of them got burnt. I'll still recommend to cover it up with tin foil, just in case - and it's a good idea to make some test pieces if you're thinking of trying this; Not all ovens are the same when it comes to heating, baking and cooking, and it'd be a shame to ruin a clay creation that you've spent time making, but I just wanted to make this quick post about the result of my experiment :)
I'll definitely be doing some more testing and figure out the minimum time frame for getting the clay to be that strong.


  1. I once accidentally overbaked clay(fimo), though I don't remember for how long, but it became Kind of puffy and almostdoubled ist size, also it became a dark Brown Color, even translucent and white pieces. I think it also smelled pretty grossly, and since I've read once that polymer clays can develop toxic gases when they bake, I would be very careful with overbakinf, especially when it starts to smell unnormally or something...

    1. If the oven is too hard on the clay, it will burn.
      I once read (someone telling a real story) that this person had left the house but forgot to turn off the oven and take the clay out. Her pet bird had been there and was fine. I really don't think it's that toxic, and if you air out the room, it should be fine. I only think the fumes develope when the clay burns.
      I live my life on the edge lol - I'm using epoxy glue, acetone and other Chemicals, so I don't think the polymer clay is the worst thing :)

  2. I have run into the problem where the clay seems to be overcooked and it just ruins the whole project. The key is some polymer testing to see what temperature works best for your oven and what type of clay you are using. Polymers are all different so like I said use some testing until it works the way you want it to.