Simple Tips To Avoid Burning Your Polymer Clay

Avoid Burnt BeadsVideo #280: The trick is to never let the temperature spike. ~Cindy Lietz

Well it happens to every polymer clay enthusiast at some point… you place your beautifully crafted try of polymer clay beads into your toaster oven to bake, only to be greeted by the horrible smell of burning plastic and the sad realization that all your hard work has been burnt to a crisp!

Mistakenly, most clayers think this is because they have left their beads in too long… or that they had set the wrong temperature on the dial. But most often it is because their tiny oven is having temperature fluctuation issues, which can be easily solved by doing a few simple things.

Watch this video to see how I have set up my clay dedicated toaster oven to provide a more even and consistent heat…

Now each oven is different and you may or may not be able to add the same number of tiles to your oven, but hopefully this video gave you some ideas that will help to stabilize the temp in your oven.

If you have any great baking tips you would like to share, please leave a comment below.

Let’s get out there people and “Save some beads!” :)

Cindy Lietz SignaturePolymer Clay Tutor

  1. Sue F, 13 September, 2012

    Another trick is to bury your beads in bicarbonate of soda (a.k.a. bicarb soda, a.k.a. baking soda).

    I start with a thick layer of bicarb soda in an ovenproof dish. Then, if I’m making weirdly-shaped/delicate items that need to be supported during baking to keep their shape, I’ll mound the bicarb soda up or make dips in it as required, and put my items in place. Lastly, I’ll cover everything with another thick layer of bicarb soda (piling it up over the mounds if necessary) before popping it all into the oven.

    Remember to allow extra baking time because the bicarb soda takes a while to get up to temperature.

    This approach does three good things at once: it supports your clay so you don’t get distortion or flat spots; it keeps the temperature very even; and it avoids discolouration from things like exposure to the heating elements, fumes from residue in the oven, etc. (I personally prefer this to the tenting approach.)

    Some people do the same thing using cornflour (a.k.a. cornstarch) instead, BUT if you use Kato Polyclay, NEVER use cornflour/cornstarch for this because it will seriously weaken the clay. It’s like with Kato in particular cornflour in volume has a super-leaching effect, and instead of being extremely strong like Kato normally is, the cornflour-immersed Kato will be very weak even if you put it into the oven within seconds of the cornflour coming into contact with the clay, and even if you extend the baking time by a large amount. Cornflour is probably OK with other brands, but bicarb soda is safe with the various brands I’ve done this with (Kato, Premo, Pardo Art Clay, Pardo Jewelry Clay, Fimo Classic, Fimo Soft) so I don’t bother with anything else. (Bicarb soda also holds the heat better, which is another plus from my point of view.)

  2. Dixie Ann, 13 September, 2012

    Sue, thanks for the great tip on the baking soda. I have always used corn starch and premo clay never knowing you could substitute the starch for baking soda. Can you tell us approximately how much time we should allow to heat up the baking soda along with the 1 hr. baking time? I also plan on getting some tiles like Cindy suggested.

  3. Sue F, 16 September, 2012

    Hi Dixie Ann,

    Sorry for the delay in replying!

    I think the key thing is that as long as the temperature doesn’t exceed the safe range for your brand of clay*, extended baking is not a problem.

    So, while “it depends” is a bit of a cop-out for an answer, it really does ;D and if you’re not sure, it’s best to bake your items for longer than you think is necessary.

    I adjust the extra time somewhat according to how much stuff I’m baking (e.g. it fits into an ovenproof cereal bowl vs it fills a large deep baking dish). And since clay strength is really important to me, I even add extra time if I’m baking something on the tile that I’ve constructed it on compared to baking it on a metal form or suspended in mid-air.

    As an indication, a largish sculptural Kato bead that I might bake at 150C/300F (or slightly higher) for about 40 minutes on its own would probably get about 50 minutes or a bit more when baked immersed in bicarb soda.

    I don’t use Premo much — I haven’t even got around to getting any of the not-so-new-anymore “new” Premo colours yet! — so I haven’t got specific bicarb soda baking times for that brand, but I’d think that another 10-15 minutes on top of the hour would be fine. That’s what I’d do until I got around to doing a rigourous test, anyway!

    * That said, my normal polymer clay oven — which is NOT a toaster oven — has minimal temperature fluctuation and doesn’t spike at all, so when I do use Premo it’s normally in conjunction with Kato anyway, and I bake the whole lot at Kato temperatures. Kato temperatures are pretty high for Premo, but I’ve never burnt anything. (On a few occasions I’ve even deliberately baked Premo translucent at higher-than-Kato temperatures for many hours, and the end effect is like amber: golden brown and almost perfectly clear. The first time I did this was just to see what happened, but it was such a cool effect that I’ve done it deliberately a few times since then. Such extreme over-baking definitely wouldn’t be safe to do with an oven that had temperature spikes, however!)

    I hope a bit of that is useful! :)


  4. Karronkay, 13 September, 2012

    Great idea. If you are looking for some very inexpensive tiles try your local Habitat for humanity store I get all mine from there, a, penny each, many different sizes

  5. Dixie Ann, 13 September, 2012

    KarenKay I watched your video again with Cindy as I was showing it to a friend of mine who loves flowers. She was amazed you made them all out of clay. We wondered if you also made the twigs, stems, etc; out of clay?
    Can you fill us in a little bit on your technique?
    She thinks you used flower wire and wrapped them and I am thinking you made them from clay and wrapped them. There is a lunch riding on your answer so please tell all…..

  6. Cindy Lietz, 13 September, 2012

    I’m afraid Dixie Ann you may be out of a lunch!! lol I don’t know if Karon will come in and give away all her secrets or not, but I can tell you that she uses real twigs in some of the cases as additional accents and uses floral wire in most every other case. If she did make any twigs from polymer then I will let her come in here and correct me if I’m wrong. ;)

  7. Karonkay, 14 September, 2012

    Dixie Ann,

    Wish I could tell you that you get lunch , but Cindy is correct The only two that do not have floral wire currently is the sunflower ( the stem was not finished yet when Cindy saw it) and the needles of the pinecone but the twig you see is real. I have incorporated the branches of real trees for the flowers that actually grow on trees. I did see a very cool tut on doing the stems out of polymer for the roses and think I might try that for a few of the roses. Due to the extent of the project and time constraints the floral wire works best for this part of the project.
    The other issue that Cindy and I discussed as I was deciding whether to do the branches out of polymer clay or use real was the fact that my oven is not large enough to accommodate the height needed for the branches and they would then need to be done in sections and wired anyway so I chose real branches and it does give it an air of reality.
    Sorry you lost your bet, but would love to buy you lunch should we ever get the opportunity to meet in person.
    I love this clay family we have here.
    Hugs Karonkay

  8. Dixie Ann, 14 September, 2012

    Karonkay and Cindy, I did not mind losing this bet, it was a win-win situation all the way around, I still got to go out for lunch! and…..I learned a lot about Karens flower making which was worth buying lunch which I did yesterday and then toured the new huge Joannes Store that just opened. I complained bitterly to the management when I found they had not updated their premo clay line. I told them I belonged to the biggest family of clayers from all over the world and how disappointed we are when Joannes does not keep up on stocking all the latest clay colors and would they prefer we purchase at Michaels. I can’t believe the positive response I received. So we do make a difference. By the way, lunch was delicious!

  9. Mrs Rainbow, 15 September, 2012

    If there had of been a Facebook style LIKE button at this point.. I would have clicked LIKE! :D Good for you Dixie Ann! :D

    Ps… Wish we could ‘LIKE’ things here! :D

  10. Patt W, 14 September, 2012

    Tricks of the trade ! Such good ideas. Way back yonder -a long time ago. I read to ALWAYS cover your beads. So I do, Always. To date, I have never had a burned bead. Maybe luck, but I think it is that the beads are covered. Try it -you will like it. I use alum foil, but you can use whatever works for you. Cindy, I am so glad you told everyone about this. It has been a lifesaver, more than once.

    As for the tiles. You have got LOTS of them. As Karonkay says, go to Habitat, if you have one close by. They have all sorts of good stuff, look around. Treasures for sure.

    Cindy bakes at 265. That is the best temp for me. So again I do it. I have a convection oven, and it took time fiddling around to get to exactly 265, but well worth it.

    Cindy has really tried all the stuff she teaches us – SO WE DON’T HAVE TO. Thank you Cindy for all your good work, we apreciate all you GOOD work. You learn so much here. From Cindy all the wonderful clayers who help out. The is the most wonderful site ever…… smile

    A HUGE HIP-HIP-HOORAY for the Lietz team !!!!!!!!!!!!!!

  11. Dixie Ann, 14 September, 2012

    Hi Patty, Cindy always says to use a piece of folded cardstock to cover your beads but you use foil.
    After my cardstock caught on fire I am thinking of switching to foil. Does using foil have an effect on how dark your beads get? I always thought foil kind of drew the heat to the item in the oven which helped
    it get hotter. Maybe I have it backwards? does it perhaps help keep the heat shielded?

  12. Cindy Lietz, 17 September, 2012

    I prefer to use cardstock Dixie as long as it isn’t near the burner of course. The problem I have had with foil is it leaving shiny spots or scorch marks if it touches your beads while baking. That won’t happen with the paper tents.

  13. Dixie Ann, 17 September, 2012

    Cindy that is good to know. What I ended up doing was taking a piece of card stock and covering it with aluminum foil then folding the whole piece in half and tenting. The cardboard side is facing the clay and the foil side is facing the heating element rods. It worked great!

  14. Natalie Herbin, 21 September, 2012

    Hi Patty
    I too have been using
    U convection oven foru beads … Less fluctuation in the temperature… Only question when I cook in a convection Oven I was told to reduce the temp by 25 degrees…. Do we do the same thing when baking the polymee clay…. Right now I bake it about 250 and the inside oven gets to about 265 .. Within the premo baking range
    Natalie H

  15. Elaine Faulks, 14 September, 2012

    Tiles are great.

    I was dumping some garden waste at our recycling depot and discovered a huge skiip, full to the brim with all manner of tiles. It was a very hot day so I offered the two guys on duty an ice-cold coke in exchange for me raiding their skip. Managed to salvage ten perfect ones, (fair exchange!)

    I use one next to my laptop and a pencil to jot down notes, ideas etc. Easy to wipe off with baby wipe and never gets lost of (borrowed) unlike my notebook, and also saves trees!

    Big thanks CINDY as now I will haul out my tiny toaster oven that I threw into the back of a cupboard in dispair when I couldn’t get it to bake my beads without burning them. Will use your tile method……….

    A good tip for making (thicker branches to support your flowers) if you do not have heavy duty wire.Twist two of three thinner wires together. TEAR some tissue paper into narrow strips (don’t cut it )Dab or paint the strips with white craft glue and wrap around wires. Not evenly, leave it bumpy and add more in parts. Have a natural branch next to you to copy. It will get lovely and messy. Bend and shape, adding more tissue to make it look natural. Leave to dry then paint a base colour and sponge on different shades to imitate nature. Seal with PYMII if using water colour or poster paint. Oil and Acrylic are fine and do not really need sealing. You can add the flowers, leaves, buds etc before you paint the main stem but I find I can add these after and use more glued tissue paper after poking the flower stem wire into the main branch, then painting the smaller stem with the base colour and dabbing on the other shades. Warning…..only do this if you enjoy getting really messy and wipe up spills as this glue dries quite hard…………….cheers xx……………….

  16. Karonkay, 14 September, 2012

    Thanks for the tip on the branches. I will have to try that when I get a chance. For now real will have to suffice as my deadline nears and I am still about three hundred shy of accomplishing my goal date.
    Thanks again,

  17. Elaine Faulks, 14 September, 2012

    Added note………
    Although using natural branches and twigs is fine they can dry out and become brittle over time. The advantage of using tissue covered wire is they can be carefully bent into different arrangements and will hold their new shape. I keep the mixed paint colours in tiny pots in case I need to either do a quick repair or add an extra stem or even cut something off that doesn’t look quite right…………………………………….cheers xx………………………….

  18. Michele Dickey, 14 September, 2012

    The tile idea is great! I had put one in the bottom of my toaster oven but hadn’t thought of really filling it up. Especially since I have my oven in the garage. I was realllly bad at burning things in the beginning and knowing the fumes where toxic I just had to move it to the garage. I like it out there but… During the winter I was really worried about the temp and how to keep the oven from cooling off too much. I actually make pottery and have MANY tiles! I will be making a little fortress around my oven before it gets too cold out. Thanks for this video and all of the comments as well. I have a question about using corn starch on my Kato clay. Is it not a good idea to even use the corn starch to remove finder prints from the kato clay projects? I’ve used it in the past and had some problems so I’m wondering if this may be why. Great info in these comment sections!!

  19. Cindy Lietz, 17 September, 2012

    From what Sue has said Michele (and you can trust her, she is very thorough with her testing), it sounds like baking soda is a better bet to use with Kato Clay rather that cornstarch. Let us know how it works for you.

  20. Sue F, 18 September, 2012

    Hi Michele,

    SMALL quantities of cornstarch, for example when used as a release medium for moulds and texture sheets, or as you say to smooth out fingerprints before baking, are generally OK with Kato.

    As an aside, however, a really neat trick that I learnt from Christine Dumont is to use PearlEx or some other very fine mica powder for those kinds of things instead. As well as being Kato-safe you can get some super effects!

    In any case, you just can’t bake Kato in contact with a lot of cornstarch (e.g. immersed in it) without it becoming incredibly weak.

    You shouldn’t leave other brands immersed in cornstarch (or sitting on a lot of it) for LONG periods before baking because the cornstarch leaches the plasticisers out of the clay, but normal making-to-baking time doesn’t have a dramatic weakening effect with other brands.

    With Kato, however, even when your item goes into a pre-heated oven within seconds of covering it with cornstarch, and even when you ensure the bead itself heats to the proper Kato temperature and stays at that temperature for one’s normal baking time or even longer (which I’ve commented about elsewhere), almost all the clay’s strength is lost. It seems to be either some sort of super-leaching DURING baking, or maybe a chemical reaction. This is really a nuisance because one of Kato’s strengths is normally… it’s strength!

    Luckily bicarb soda/baking soda works perfectly with Kato when you want to bake your beads supported by or covered with something. (As mentioned above, I use PearlEx for a non-liquid release medium or fingerprint-remover instead. My studio is basically a cornstarch-free zone now unless I’m in mad-scientist mode and am testing something that specifically requires it.)

    You didn’t say what problems you’ve had in the past, but if it has been to do with a lack of strength and you’ve only used “brush on” quantities of cornstarch (and haven’t mixed the cornstarch back into the clay when you’ve collected cut-offs and scraps for re-use, for instance), my guess would be that the baking temperature wasn’t hot enough, or that it didn’t stay hot enough for long enough to cure the clay properly. Kato REQUIRES 150C/300F and is safe to bake at somewhat higher temperatures than that. There is a significant strength drop-off if you bake Kato at typical Premo temperatures of 130-135C/265-275F, for example, and lower Fimo-range temperatures are even worse. (As I noted above, since Kato is my main clay, if I happen to use Premo for a change I generally end up baking the Premo at Kato temperatures!)

    Or if the items initially seem strong but weaken over time, it could be that the clay in the centre wasn’t properly cured. Baking for longer can help with that kind of thing, whatever brand of clay you use. Another approach is to use something else as a bead core so that there’s only an outer layer of clay that needs to be cured (beads that didn’t turn out right make good bead cores :D), and so that you don’t need to use so much of your good clay per bead. Just make sure that whatever you use as your bead core won’t expand during baking or it can crack your outer layer of clay (although you can recover from that by finishing it in a way that looks like you’ve deliberately distressed it; polymer clay is amazingly versatile!).

    I hope that helps :)


  21. Maureen P, 15 September, 2012

    Just a word on burnt beads. A few years ago I made a batch of tubular beads in a sort of African style, black, brown, beige and white. I forgot the oven and burnt them black. For some reason, I put them away instead of tossing them. Over a year later, while sorting old beads, I came across a plastic bag of gorgeous dark beads. They were black, but had brown and lighter brown swirls that looked like they were deep in the material. Very subtle. I could not for the life of me remember where or when I bought those beads. Of course, you see the end coming – they were the burned ones, seen with new eyes. That’s called serendipity – a happy accident!

  22. Cindy Lietz, 17 September, 2012

    Excellent point Maureen!

  23. Anna, 17 September, 2012

    I have a convection oven. Since the heated air is supposed to swirl around in there, should I still be doing tenting?

  24. Cindy Lietz, 17 September, 2012

    Do you have problems with scorching Anna? If not, then don’t worry about it. If you do though, it wouldn’t hurt to try. Let us know if it works for you.

  25. Dixie Ann, 21 September, 2012

    I went and got some ceramic tiles for my oven like Cindy suggested and interestingly enough my oven temp spiked to 305 degrees after laying tile in the bottom, the middle shelf and on top of the oven. I had to back my temp down 25 degrees. Not only does the oven take longer to heat up but it also stays hotter longer and then of course it takes longer to cool down. Having a convection oven I was used to setting my temp dial at 250 degrees because it always baked at 275 degrees. With the tile in place I have to set my temp dial down to 225 degrees to maintain the 275 degrees. Premo clay bakes at 275 degrees so no matter if I use the tile or the oven without the tile, I am getting 275 degrees consistently. I guess my question is… it better for the oven to use the tiles baking at 225 or with no tiles at 250? Can anyone comment on this since now I am confused and don’t know which way to bake. I am thinking maybe the newer ovens (mine is less than a year old) have improved a lot over the older ones. Comments….please!

  26. Cindy Lietz, 28 September, 2012

    Sorry Dixie to not have gotten back to you earlier. I am a little confused… what is the problem exactly? It doesn’t really matter if it takes longer to heat up or cool down. It just means it is holding the temp more stable. And if you can just adjust the dial a bit to get the temp you want, then why is that a problem? Sounds to me like everything would bake properly in your oven with or without the tiles, so it really is up to you as to which method works best for you. Sounds like a nice oven, if it is not spiking without the tiles. What brand is it?

  27. Dixie Ann, 28 September, 2012

    Sorry to confuse you Cindy, I have an Oster Convection Toaster Oven and it only heats up in 25 degree increments. By using the tile like you suggested in the video it spiked to 305 degrees so I started removing one tile at a time to get to my 275 degrees. The oven did cool down a few degrees but by using the tiles I could not get the oven to heat evenly as I cannot adjust the temp.knob within a 25 degree setting. I finally took out all the tiles except one and set the oven to 225 degrees. It heated up to 275 degrees and stayed there. If I use no tiles and set the temp to 250 degrees, it heats to 275 and stays there. I just didn’t know which way was the best way to go but you answered my question. Either way will work. Now I am going to dig out my old oven and use your neat idea on it. Thanks so much.

  28. Genie Keating, 12 January, 2013

    Hi Cindy

    I discovered some information about microwaving polymer clay. What do you think about it?

  29. Cindy Lietz, 12 January, 2013

    Hi Genie, Yes I am aware of the information about microwaving. However, I do have concerns about baking polymer clay in a water bath in the microwave. Water boils at 212F which is essentially what is happening when you are cooking in water in the microwave. Premo clay needs to be cured at 265F-275F… 212F is just not hot enough. Plus if the water runs dry it can burn in the microwave very quickly and very badly. So I have an issue with recommending it.

  30. Jocelyn C, 10 April, 2013

    Thinking about this Oster Convection Oven model, soon? Does anyone have any helpful comments or feedback? Sure appreciated if you do. Worried that cannot see where you can set an exact temperature (see pic at link), but, hope the digital jellie makes it possible. It’s bigger, convention, and still fits where it needs to go, lol.

    Item Description

    The Oster Designed For Life Extra-Large Convection Countertop Oven is an ideal oven for large families. With its conventional cooking technology, it spreads heat evenly all around the cooking area thereby retaining the true flavor of your food. This countertop oven provides an extra-large interior that can accommodate a frozen pizza, a whole chicken or even a 13-by-9-inch pan. The brushed stainless finishing of this Oster countertop oven gives it an elegant look to complement your kitchen decor. The interiors are easy to clean. The easy-to-use digitized menus of this countertop oven offers easy selection from the wide range of options such as baking, broiling, pizza, toasting, and defrosting. This Oster countertop oven comes with an user-friendly digital control panel for convenient operation.
    Oster Designed For Life Extra-Large Convection Countertop Oven :

    Accommodates family sized frozen pizza, a whole chicken, roasts or casseroles
    90-minute timer with automatic shut-off
    Removable crumb tray
    Cooking functions include Bake, Broil, Toast, Pizza and Defrost
    2 rack positions allow for customizing, helpful when cooking a tall roast
    User-friendly digital control panel for convenient operation
    See-through door for checking on food at a glance
    Durable baking pan included
    Model: TSSTTVXLDG-001

  31. Dixie Ann, 10 April, 2013

    Hi Doll, that is exactly the same model as mine. I really love this oven except for one thing. The oven temperature setting. You can only set your temp in 25 degree units. It starts at 200, 225, 250, 275, 300 etc;
    If you want to set the temp at 295 you can’t. It is made this way and I don’t know of any other model on the market that will allow you to set it by the minute in these small convection ovens. Mine works out nice because I only use Premo clay and I bake it at 275 degrees which it does a really nice job. When I used Pardo clay translucent with my premo I baked it at the same temp and it also came out fine even though Pardo says to bake at 248 degrees. Thats a really good price also.

  32. Bev Kennedy, 21 November, 2014

    I have learned a LOT from your videos, Cindy — the one about putting tiles on top of the oven is a great idea. I use two toaster ovens in the class I teach (at a senior citizen center), and one of them heats hotter than the other, so I have to watch it carefully as I have scorched some of the projects. Not a good thing. We use ceramic tiles to work on, and I do have one ceramic tile in each oven, but never thought of putting them on top.

    Thank you! I’m glad I joined your group. I have been doing polymer clay for many, many years, and you come up with some things I have never thought of.


  33. Cindy Lietz, 25 November, 2014

    Thank you for your kind words Bev! I am pleased that you are learning so much from the videos. Make sure to click around and read some of the old post as well… there is ‘so much good stuff’ buried in the posts, that you might just miss it, if you don’t look around. Thanks for commenting!

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