Baking Polymer Clay Safety Tips – Fumes From Burning Not So Good

Baking Polymer Clay

Vid #006: Safety Tips for Baking Polymer Clay:

Yes even a soft, squishy and colorful compound like polymer clay has it’s own list of warnings and label cautions. But I think most people would agree that spending quality time with your clay is probably a heck of a lot safer than the morning or afternoon commute in rush hour traffic. Wouldn’t you agree? :)

Of course with polymer clay there’s the standard safety information about sensible use when it comes to working with sharp cutting blades and pointy tools. That’s the obvious stuff.

For today though, I’d like to talk about how to prevent your clay from burning during the baking process. Burned clay will create fumes that you really should not be breathing.

The very upper temperature limit for baking polymer clay is 350 degrees Fahrenheit but this varies from brand to brand (see further discussion about this in comments section below). I usually stay at around 265 degrees to be on the safe side.

And another polymer clay baking tip… It’s usually best not to rely on the temperature gauge or settings dial on your oven’s control panel. The heating elements in the oven wear out over time and that can cause inaccurate temperature readings. Use a separate oven thermometer instead. You can get them at pretty much any big box retail store these days.

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The full version of the “Polymer Clay Safety” preview video shown above, is included in my Polymer Clay Bead Making Fundamentals Course[SEE Video #6 of 39]. Besides information about how to bake polymer properly, I also discuss:

  • Using dust masks when sanding your beads.
  • Breathing metallic powders not so good.
  • Microwaving clay… Not!
  • Safety glasses and rotary tools… my “close call” story.
  • Baby wipes not just for babies bottoms.
  • Polymer clay safe for schools and children (certified non-toxic).
  • Clay really doesn’t taste good. So don’t let your kids eat it!


  1. Cindy Lietz, 28 March, 2008

    Although polymer clay is certified non-toxic, make sure to always follow the safety tips and guidelines listed on the packages of the products you purchase. Just be sensible and you’ll be fine.

    Cindy Lietz’s last blog post..Focal Beads – Handmade by You!

  2. Shateal, 13 April, 2008

    Hi there!

    Found your blog tonight
    and wanted to compliment it!

    Very cool site with a lot of information!
    I think I will put your link on my website.

    However – there is one mistake…
    regarding the UPPER temperature limit
    of Polymer clay…

    It is NOT 350 degrees….
    polymer clay starts to burn right away when the
    temperature hits 300 degrees.

    Some doll artists do bake their sculptures
    (the very last bake) using 300 degrees heat but ONLY a minute or two, and always covered with some protective material.

    Kind regards,

  3. Cindy Lietz, 13 April, 2008

    Shateal, Thank you so much for your comment! You are very right when it comes to certain clays.

    Polymer clays burn or darken at a variety of different temperatures depending on a few different variables. Different brands of clays are made with different formulations of plasticizers and therefore have different baking temperature ranges. They range from 230 degrees (Fimo soft translucent) to 325 degrees (Kato Polyclay).

    This variable in baking temps also translate to the burning temps. Another variable is color and translucence. The lighter the color or the more translucent it is, the lower the temperature it will burn or darken at. Except with Kato Polyclay and especially Kato Liquid Polyclay Clear Medium, which becomes more translucent with higher temperatures.

    The flesh colored clays with a lot of translucency that doll makers use is especially susceptible to darkening, therefore they must bake at a lower temperature than someone baking a dark colored bead made of Premo or Kato Polyclay.

    So what I’m trying to say here is read the package. The baking temperature for each clay is different and may even vary depending on the color within a brand. Use a thermometer, bake on a tile to help evenly distribute the heat and tent your beads with a folded piece of parchment paper… And never let it go above 350 degrees!

    Cindy’s last blog post..Pirate Crossbones Jewelry Pillaged in Broad Daylight

  4. Cindy Lietz, 24 July, 2008

    This question just came to me via email form Elaine: "Hi, I can’t seem to remember what temp. to bake my projects of beads, or small things. Could you please let me know? Thanks"

    Hi Elaine – The article on this page along with the dialog between myself and Shateal should help you out.

    And here’s a tip for everyone on how to best use my blog as a resource to find quick answers to your questions. At the top of each page right under the photo of me in the header section, is a small box called ‘Search’. Just type any keyword into this box and you will see a list of articles, one of which may be exactly what you are looking for.

    @Elaine: You could try the ‘Search’ technique after you review the information on this page, to find even more articles. Use ‘baking’ and/or ‘temperature’ for your keywords.

    @Everyone: If you don’t find what you are looking for using the search box, feel free to use the ‘Contact Cindy’ form like Elaine did. Or better yet, just post a question in the comments section of an article that seems to be a close topic match for your question.

    Last post..Mokume Gane Polymer Clay Canes for Pendant and Bead Jewelry Making

  5. Corinne, 18 January, 2009

    Hello Cindy :-)

    I’ve read some article on the net a while ago that someone cooked the fimo beads in the microwave, with about 5 cm water above the beads, for 15 minutes. I love trying out new things, so I gave it a try. The beads came out hard, the colour is a bit lighter than the original, but I think it’s a great way – and a shorter one – to “cook” the beads.

    Wish you the best and thank you for being such a great teacher.

    Corinne Langshtad

  6. Cindy Lietz, 18 January, 2009

    Hi Corinne! I know a few people bake their beads in water in the microwave but I don’t recommend it, because of the potential for burning and toxic fumes. If you like the way the boiled beads turn out, I would recommend boiling them in water on top of the stove instead. It safer. Make sure not to let the water boil dry though or you will have the same problem.

    I love it that you like to experiment… so do I! I just want you to be safe. Thank you so much for that comment!

  7. Cindy Lietz, 24 January, 2009

    INFORMATION UPDATE… about the fumes that can happen when you burn your polymer clay in the oven. I just posted about this important polymer clay safety topic in another thread. So rather than re-posting the info here, simply follow the link by my name above to go to the original post.

  8. lemondrop, 21 March, 2009

    i would like to ask if its still safe to bake food in the same oven where you bake your clay?


  9. Cindy Lietz, 22 March, 2009

    Good question lemondrop. On the packaging the clay says nontoxic and that can be cured in your home oven. It says nothing about whether or not food can be baked in the same oven or not.

    I think the safest thing to do is to keep all food and clay items separated. For me this includes baking my beads in a toaster oven that is dedicated to ‘clay only’.

  10. Kristin, 11 September, 2009

    Is it safe to bake the Pledge with Future Shine product that you use? I looked at the product and couldn’t find an ingredients list so I couldn’t even look it up myself. Thanks!

  11. Cindy Lietz, 13 September, 2009

    I know a lot of people that bake Future Floor Finish on their beads with excellent results. I haven’t noticed any fumes coming from the oven when baking Future myself but how safe it is I have no idea. Sorry not to be of better help.

    I do know you can safely bake Studio by Sculpey Glaze. If you want more info, click the link by my name.

  12. Eunice, 14 September, 2009

    My electric Oven is getting on my nerves .
    you see , there is this heated setting , divided to the top , bottom and both sides . Which one should i tune to ? Or should i just off it ?
    Will the oven bake my clay without the heater ?
    Because i tuned to both sides for approx. 10 mins and WOW , fumes and very very toxic smell !
    Advice asap! thank you !

  13. Cindy Lietz, 14 September, 2009

    Hi Eunice,

    Welcome to the site. You are experiencing a problem that many other beginners face. The short answers is that you need to get a “reliable” oven thermometer. Your oven is heat spiking high enough to burn your clay and cause fumes. You should never trust oven dial settings for your temperature readings.

    This topic has been discussed many times here at the blog. If you use keywords like ‘baking’, ‘bake’, ‘burn’ or ‘burnt’ in the search box at the top of the page, you’ll get a long list of helpful articles. Be sure to read all of the comments following the articles too.

    The “Burnt Polymer Clay Color Blends” link by my name above will take you to one comment thread in particular, that should be helpful for you.

    Also, this topic of how to bake polymer clay properly, is covered at length in my 39-part polymer clay basics video course, if you want to check that out.

    Hope this helps.

  14. Eunice, 15 September, 2009

    Thank you so much ! =)

  15. Julie, 02 October, 2009

    Hi, I’m thinking of taking up polymer clay sculpting. I live with my parents & I don’t have room for a toaster oven. I am aware of the fume issue & I don’t want to have to clean the oven all the time (since we cook with it often). I thought of the idea of buying a lidded roast pan just for this purpose alone (not for cooking…ever!). I can put my sculpture in the pan (lined with terracotta tiles on the bottom) & bake it (with the pan as my ‘kiln’, so to speak). What do you feel about this idea? Can it be done & materials (type of pan) would you recomend?

  16. Cindy Lietz, 02 October, 2009

    @Julie: Sure that will work. An even better solution is to use a clay dutch oven (a clay version of the roaster pan). They hold the heat more evenly than a tin foil roasting pan. You can sometimes find them in a second hand store. But the tin will work if it’s lined with tiles and your pieces don’t come too close to the lid.

  17. sam, 06 January, 2010

    I am using clay for the first time. I have young children (ages 3 and 4) and was wondering if the clay is safe to handle for children once is has been cured (I used sculpey III clay)? Or would the safety precautions (i.e. washing your hands thoroughly) that apply to the handling of clay prior to baking still apply?
    Thank you,

  18. Cindy Lietz, 06 January, 2010

    Sam, once the piece is baked, your kids can play with the items like they would any toy. Of course they can’t chew on the baked clay. But you wouldn’t want them to do that anyways. :-)

  19. sam, 07 January, 2010

    Thanks so much for your help with my question about baking polymer clay safely. I also really appreciate your promptness! Have a good day! Sam

  20. Jocelyn, 07 January, 2010

    Also remembering that some folks use aluminum foil to seal up the polymer clay prior to baking so that they can use their regular ovens without cleaning. Just take the package of finished beads outside to unwrap the foil, and you have successfully eliminated any fumes or contamination. Probably could even re-use the foil wrap if you are careful.

    Won’t work for me, I need to see the baking process. Use a lot of translucent, which darkens quickly, and need to keep an eye on progress.

  21. James Peacock, 06 June, 2010

    You usually state to bake for one hour. Yet, the package instructions indicate baking for 30 minutes (unless I’m mistaken). Have you found the Hour Baking the best?


  22. Phaedrakat, 07 June, 2010

    @James Peacock: Absolutely! Cindy explains it best in this comment — why you should bake polymer for an hour.

    The directions are for 30 minutes at the perfect temperature. Unless you have a perfect oven (and who does?) the temperature fluctuates, spiking up, then lowering, again & again. By baking for an hour, you ensure that the clay gets that 30 minutes at the perfect temp, without burning. If you only bake for 30 minutes and the clay does not completely cure, you might even be able to tell. But some time later, the uncured plasticizers will start to eat into the cured parts, and your piece can be ruined.

    Baking for an hour will make your beads nice and strong, much harder and easier to sand. Be sure to use an oven thermometer to monitor the temperature, and bake on a ceramic tile, or in a bed of cornstarch for pieces that need support. You can also bake beads on a bead rack, (which you can set on a ceramic tile to help the oven temperature stay more even.) For additional tips and baking tricks, check out this article, called Instructions For Baking PC Beads Properly.

    It has links to quite a few of the best baking articles here at the site. The first one on the list is called “It’s OK to Break the Rules When Baking Beads,” and talks about the very subject you’re asking about (baking longer than the pkg. directions say to.) These are great articles to read up on, as they have tips and information, and lead to great discussions (which are in the comments below them.) Be sure to read the comments, since there’s often more info there than in the article itself.

    You can also use the search box at the top left of each page if you’re looking for info on another subject. Type in a word or phrase like “baking for an hour” or “ceramic tiles” or “using cornstarch” etc. to find articles, comments, or Q & A on any topic you like. If you can’t find the info you need, leave a comment, and someone will be happy to help! Have fun!


  23. James Peacock, 07 June, 2010

    That was a very well done explanation of your theory. You made me an instant believer and I’m changing my baking approach immediately. Thank you so much for taking the time to — no only answer my question – -but to answer it so completely and with the scientific bent. That truly helped me.

    Again thanks

  24. madison, 13 August, 2010

    Hi, is it safe it inhale the burning of the clay after it has been cured?

  25. Linda K., 14 August, 2010

    @madison: If the clay is burning at any time and giving off fumes, you don’t want to be breathing it.

  26. patricia, 24 September, 2010

    I have to thank you so much for posting this – the information is amazingly thorough.

    I have a question, however: we’re about to buy a new toaster oven, but for now we’re sharing the current oven between food and clay. I don’t think they sell oven cleaners where I come from, so I’m wondering if soap and baking soda on the oven’s walls are good enough to clean it after every curing.

    Thank you so much!

  27. Phaedrakat, 26 September, 2010

    @patricia: Hi Patricia…Cindy’s site is filled with tons of info, isn’t it! Her videos are amazing, as well…in case you haven’t seen them yet, you can get 3 free just for signing up for her newsletter. You also get free color recipes each week. The sign-up link is at the top of the page.

    Your question…yes, soap & soda should certainly do the job. However, you can avoid most or all of the cleaning if you cover your baking pan, or use a dutch oven (or similar.) Use caution opening the lid…you’ll want to avoid inhaling the fumes! Jocelyn has a tip about that in her comment above. If you use foil to cover the pan, be sure that it doesn’t rest on the clay. Instead, cover loosely…sealing the edges tight to hold any fumes inside. Avoid letting any metal touch your clay if you can…it gets hot very quickly, and can burn your beads.

    I wanted to draw attention to the directions above…the part about using a separate oven thermometer. Most oven dials are way off the mark…& the curing temp for clay is critical. Be sure to monitor the temperature throughout the curing cycle, so the oven doesn’t get too hot. As long as you do this, you can bake your clay (pretty much) as long as you like. Cindy recommends baking for at least an hour, so you get a complete cure — and nice strong, hard beads. (Bake even longer for thicker pieces.) There are lots of other baking tips/tricks all over the blog — use the search feature to find them, or try the links next to Cindy’s name in the comments above. They lead to even more great baking articles, as well as additional info and Q&A in the comments below the posts. Hope this helps!

    Good luck & happy claying…hope to see you around~ ;·)
    Oh, & have fun! ~Kat, Riverside, CA USA *Where are you from?

  28. Patricia P, 27 September, 2010

    @Phaedrakat: Thank you so much for the response! :) I’m not so sure about our availability of materials as far as the dutch oven, because I live (don’t wanna put anything in specifics… :)) in the Philippines. Claying is a growing but already popular way of earning around here (there are a number of inspiring stories to learn about clay business), but I’ve only started around 2008, and even then cheap Sculpey was difficult to find.

    And yes, unfortunately, I’ve learned NEVER EVER to leave clay unattended firsthand, a lesson I’ve kept to mind (although traumatically) every time I cure anything.

    Again, thank you so much for the response! This certainly won’t be the last time I’m coming around here. :)

  29. Neg, 24 May, 2011

    Hi Cindy! I was wondering how long I should bake my clay if I put it in at 265 degrees and about what to put the clay on since our clay didn’t come with accurate enough instructions. We don’t have a kiln or a tiled rack, so is it O.K to put it on a metal pan or can I put foil on the pan, too? Thanks a bunch!

  30. Cindy Lietz, 26 May, 2011

    @Neg: Hi Neg, welcome to our clay family! I like to bake my pieces for an hour in a toaster oven and prefer to use a ceramic tile to bake on rather than a metal pan. This avoids getting spikes in temperature that may cause your clay pieces to burn.

    There are tons of articles and tutorials on this site that will help you. Just type ‘baking’ into the search box at the top of the page for a big list of information.

    If you are new to polymer clay, I also suggest you purchase the Polymer Clay Basics Course. There are 39 videos that will help you to avoid going through the mistakes that most of us make when just starting out. Click the link by my name for more info on that.

  31. Vicki Irvine, 22 November, 2019

    Hi. I want to ask a question. I am trying to make a frame for my mirror clocks and a friend of mine that works with polymer clay said that it might be my best bet to making a frame. However, I don’t know where to start with this. I’ve never used polymer clay, and am worried that I will wreck my parents oven or burn the clay, causing smoke to fill the house. What I think would be the best way to do this is to lie the clay next to the clock and flatten it to the clock and then remove it and bake it and then use glue to adhere it to the clock. Please help me with this in giving me the best way to try and attempt to do this. Thank you in advance. Have a wonderful day.

  32. Cindy Lietz, 29 November, 2019

    Hi Vicki, yeah you probably don’t want to put your clock in the oven. It could melt. Do the method you came up with. That’s your best bet. Good luck! (Oh btw, I have tons of baking videos that you can watch that will definitely help. Just do a search at the top of the page to find all the beginner info you need.)

  33. Darra I, 10 November, 2020

    Hi, can I ask if you know why my baked polymer clay smells so bad? Almost like burnt plastic. But it isn’t burn or underbaked. I have left it out to air for days but the smell is still there? I’ve googled but it seems to be happening to no one else? Why does this happen? How can I get rid of the bad smell? And how can I prevent this from happening again? Thanks a lot!

  34. Cindy Lietz, 10 November, 2020

    Hi Darra? What brand are you working with? Some brands smell much stronger than others.

  35. Darra I, 11 November, 2020

    Hi Cindy, unfortunately I’m unsure which brand is it because I got it off Shopee and it’s all in Mandarin Chinese. What brands smell less and is there any way to lessen the bad smell? It’s a pity because I still have quite a bit of polymer clay to use from this batch and don’t want to waste them:(

  36. Darra I, 12 November, 2020

    Hi Cindy, unfortunately I do not know the brand of the polymer clay as it was bought online and is Mandarin Chinese. Would you have suggestions of less smelling clay brands? Also, do you know how I can minimize the smell after being baked since there’s still quite a bit of clay from this batch and it’s such a pity to waste it! Many thanks!

  37. Cindy Lietz, 13 November, 2020

    If the clay still smells strongly after baking, I don’t think there is much you could do to minimize that except perhaps totally incasing it in resin or another brand of clay. If it seems to be a decent clay otherwise, you could use it to bulk up armatures in sculptures or use it as bead and pendant cores, that you cover in cane slices or veneers.

  38. Darra I, 15 November, 2020

    Hi Cindy, I see. Thanks for sharing your advice, I really appreciate it:)

  39. Jasmine D, 06 July, 2022

    Hi there. I dont know where else to ask and i have searched every where. Im new to polymer clay. I have read the directions on baking and have watched your videos. Well a few. That being said. Is polymer clay supposed to have a very strong melted plastic smell? I have searched and cant find an answer. My entire kitchen smells like ive been melting plastic all day. Am i doing something wrong? Please help!!!!

    Thank you

  40. Cindy Lietz, 07 July, 2022

    Hi Jasmine, polymer clay can have a strong melted plastic smell… especially certain brands. Kato Polyclay for example is such a strong smell, even when it is raw, that I can’t work with it. Premo and Souffle have a slight smell, and other clays like Cernit, Pardo and Cosclay have very little smell at all. If the brand you’re using bothers you, you can try another brand. If the smell still bothers you, you can bake inside a Dutch oven, turkey bag or a tinfoil cake pan with another pan flipped over on top to make a lid. Hope that helps.

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