How Long to Bake Polymer Clay?

So you’ve made your polymer clay figures, beads, or charms and you’ve read the instructions for baking. You set your oven’s temperature and preheat the oven. You calculate how long to bake polymer clay. And you set the timer and wait. But…how can you tell if polymer clay is baked enough?

I asked my husband this question, and the cheeky sod answered back, “You know polymer clay is fully baked when the timer goes beep, beep, beep.”

Yeah well. That’s not the answer. But seriously, how can you tell?

It’s really common for new clayers to notice how flexible their baked polymer clay is and assume that it’s not fully cured. But actually, that has nothing to do with it. All baked polymer clay is flexible to a degree after baking, and some brands are downright bendy if they’re thin enough. (It’s not so noticeable if a piece is very thick.) This is because polymer clay is actually vinyl and just like an old vinyl record, it’s flexible. (How flexible SHOULD it be? And should it always be flexible? What if you can’t bend your clay? Read more here.)

Flexible polymer clay is not underbaked
Polymer clay should be flexible when it’s fully baked. But if it breaks, it’s not baked long enough.

Polymer clay is a moldable plastigel made of PVC particles suspended in a mixture of plasticizers, fillers, stabilizers, lubricants, and colorants. It becomes less viscous (runny) as the temperature increases. That’s why body heat and summer temperatures can make polymer clay too soft. But once the temperature increases to a certain point, the vinyl particles in the clay begin to fuse together and the clay mass begins to harden. The clay must stay at the right temperature long enough for the particles to fully fuse, making a strong final result. If you don’t bake your clay long enough, the fusion will not be complete and the clay will easily break and crumble.

How Long to Bake Polymer Clay?

But how long is long enough? Underbaked polymer clay looks just like fully baked polymer clay. You can’t really tell by feel if the fusion process is complete. The only way to tell is to actually attempt to break a piece. Fully baked polymer clay will bend before it breaks.*** Underbaked polymer clay will snap in two or crumble when you try to break a piece in your hands. Now obviously that’s not the best way to check because you run the risk of breaking your clay creation. Not a good strategy!

Underbaked polymer clay will easily break, crumble, snap in two, or chip when carved or drilled.

***(Note: Sculpey Original and Sculpey III are both brittle and will often break easily with your hands, even when fully baked. I nearly always recommend using stronger clay brands such as Premo, Souffle, Fimo, Kato, Cernit, Pardo, and PVClay when you need a strong, durable clay or if you’re having breakage issues.)

Know Your Oven

The best strategy is to know how your oven works and know how the clay behaves in it for various temperatures, times, and thicknesses of clay. First off, make sure you have a good baking setup including an adjustable oven, baking pans, and a separate oven thermometer. Experiment with your oven to see what setting needs to be used to get the temperature that your clay requires for curing, this could be from 230°F (110°C) to 300°F (149°C). Watch the thermometer through the door and see what happens to the temperature throughout the baking cycle. Be aware that the temperature dial on most ovens is wildly inaccurate. Adjust your oven accordingly to get the desired temperature.

Then do some tests. Make bits of clay in various thicknesses and bake them for varying amounts of time. Keep track of it on paper (you won’t remember…trust me). And then once they’re cooled try breaking the pieces. You’ll see right away what baking times work best for varying thicknesses of clay. You’ll also notice that the strength of clay keeps going up with bake time, too, and baking a really long time will give you much stronger clay. This is a good thing to know when you need extreme strength for a specific project.

Many people with dedicated claying ovens just adjust it to bake at one temperature and they never touch the dial after that. Others have marked where the “Fimo, Premo, and Kato” settings are on their particular oven. The bottom line, though, is to know your own particular oven.

Bake Longer “Just in Case”

Of course, if you don’t want to mess with running tests, just bake “longer”. If you ask most polymer clay pros they’ll say they bake everything for an hour. Or longer. And for thicker and larger pieces they might bake for several hours. Longer baking will NOT burn your clay. Longer baking will also lead to stronger clay projects.

If your clay is burning, the temperature of your oven is too high. Address your temperature, not your bake times!

That being said, longer bake times can cause some colors of polymer clay to darken. White and translucent can turn slightly amber or brown. Red, yellow, and fuchsia can darken. This does not mean the clay is burned. To prevent, or at least reduce this tendency, make sure you always cover your polymer clay projects while baking. This can be as simple as a piece of aluminum foil over the top or as complicated as a set of dedicated roasting pans. Covering your clay will shield it from the oven’s heat and dramatically reduce color shifts that happen during baking.

Package Recommendations

So why do the package recommendations tell you to never bake longer? Keep in mind that manufacturers have to write instructions for ALL types of consumers. And most ovens are wildly inaccurate. So they have to give instructions that give a balance between adequate curing and the very real and frustrating reality that many ovens will be too hot and could cause the clay to burn. The instructions on the package are what is going to give adequate results for most consumers. They are not designed to give the optimal results for perfect and controlled conditions. Feel free to do your best to create the best possible baking conditions for your polymer clay so that you can get the best results possible.

Fixing Underbaked Polymer Clay Projects

What if you realize that you have some underbaked polymer clay. What then? Luckily, you can bake your polymer clay again, this time at the correct time and temperature. I’ve heard that this won’t give as strong of results as if it was baked long enough the first time. But go ahead and try. It might help. Also, polymer clay can be rebaked an indefinite number of times. You can even rebake it if you’ve already added paint or sealer, in most cases.

Still Have Baking Questions?


Protect your polymer clay during baking. Learn more newbie tips at The Blue Bottle Tree.

End the confusion about baking

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Baking and Curing Polymer Clay

Learn about the right temperature, times, ovens, and baking setups to ensure optimal results. No more broken or scorched projects!

Protect your polymer clay during baking. Learn more newbie tips at The Blue Bottle Tree.

End the confusion 

Need baking help?

Baking and Curing Polymer Clay

Learn about the right temperature, times, ovens, and baking setups to ensure optimal results. No more broken or scorched projects!

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77 thoughts on “How Long to Bake Polymer Clay?”

  1. Boa tarde , vou cozinha-la minha peça Deus permita que der certo, já seguir seus conselhos em tudo que eu queria nesse bate papo, Obrigado!!!

  2. Could you please tell me what would be the best solution to bake polymer clay dolls with combination of Super Sculpy Living doll recommended temperature 130 degrees maximum 15 minutes baking time with Fimo recommended temperature 110 degrees not less than 30 minutes? Super sculpy is for the head legs and arms, and Fimo for clothes and hair. What baking time and temperature do you recommend for this combination? Thanks in advance!

    1. Fimo can easily be baked at 130 degrees. Bake the whole thing at 130°C for 30 minutes (or more). But do make sure that you are sure of the temp inside your oven (most of them are incorrect, so get an oven thermometer to be sure). And also make sure to cover the item with some foil, a lid, or some cardstock…just to protect it from the direct heat of the oven’s element. Polymer is a lot more temperature tolerant than you’d think. Longer, and to an extent hotter, bakes mean a stronger finished result. The manufacturers give recommendations for lower times/temps because they know that most ovens are incorrect. But if you know what yours is doing, you have more leeway. Polymer may darken, but it doesn’t actually burn til close to 175°C.

  3. This is wonderful information! I want to make the fimo decorations up the stems and onto the goblets of stemware. Please explain the details of how to bake them. Thanks!

    1. Well, that could take up an entire tutorial! But essentially you would just bake them like you’d bake anything else. People often fear baking glass, but breakage is rare. Don’t plunge it into ice water after baking, though!

      1. Sorry, just a few more questions about the details. Do I need to put them in a cold oven and then turn it on or can the glasses go in a preheated oven? When the baking is done, do I then turn the oven off and leave the glasses in until completely cooled before removing them from the oven?

  4. Hi Ginger
    I’m making a wedding cake topper with the bride and groom , they have large ( golf ball size heads) but small body’s and arms ect . What is the best way of cooking this project , I’m using fimo , not my usual sculpting material as I normally use fondant icing lol. Many thanks Andy ( Custom Cake Art)

    1. Hey there Ben. There are two main reasons for white discoloring with baking. One, it’s getting too hot. In that case Fimo turns a bit pinkish and of course any white clay can singe. And second, you can get discoloration occasionally when there’s something on the clay, such as lotion from your hands, that darkens in the oven.

  5. Hi there! I’m rather new to baking and was hoping one of you lovely people could help me out! I’m making a little figurine with a larger head but smaller body. I plan on using a foil core for the head and covering it in clay – simple enough 🙂 however the body will be pure clay – when i eventually add them all together to bake, would i have to bake it for longer to ensure the body bakes thoroughly? If so, will this then burn the jead which has a thinner amount of clay on top of the foil? I’m using fimo professional and i want to bake the head first and then bake it again with the body 🙂

    Thank you!!


  6. would love to make long thin ‘noodles’ out of polymer clay to use in micromosaics, about 3mm in diameter snakes basically. Do I need to shorten the baking time or still bake for 30 minutes? Thanks

  7. Can you please tell me if the fairy door I made from polymer clay is safe in an outdoor environment??

    1. Hi Colleen, yes, polymer clay is vinyl plastic and once cured is waterproof and weatherproof. Heat, freezing and thawing, and rain will not harm the cured clay itself. Any surface treatments such as paint, sealers, mica powders, glitter, etc. are likely to peel off eventually, however. Also, some colors of polymer clay may fade in direct sunlight. Also, mildew growing on clay creations can often stain them, just as it will stain decks or lawn furniture.

  8. hey! this was very interesting to read, thank you.
    i have not yet begun making any polymer clay charms yet as not all of my supplies have been delivered and I’ve never tried this before. I’ve been watching many videos and reading a lot of articles that will help me when I’m getting started. in a few tutorials and such, they say to “prebake” parts of the charms they are making, may i ask how does prebaking help and does it mean to partially bake or fully bake that part?
    thank you

    1. Pre-baking is really a misleading term. You don’t even want to partially bake polymer clay as it won’t bake stronger the second time. But you can bake multiple times, with each bake being a full length bake. You do this when later steps will mess up the work you did earlier. So you make the first part, bake that, then add more clay or use the baked pieces in a new design. You would then bake that. Clay can be baked as many times as necessary.

  9. I still don’t understand how to bake dolls without one side flattening. When I used baking soda the dolls just conformed to the lumpy soda. I actually hung one doll from the wire racks in the oven. It got toasted. lol. Mostly it works out ok but I need them to stand up in the oven so nothing gets crushed. thanks for your time.

    1. To use cornstarch to support a figure during baking, you’ll need to embed the doll into the clay rather than setting it on top of the cornstarch. Hold the doll in place, then pour cornstarch in so that it falls around the doll and supports it. Keep in mind that you will need to increase baking times to account for the insulating factor of the cornstarch. If your doll got toasted hanging from the rack in your oven, then your oven is getting too hot. Also, consider baking your doll at several stages during its construction rather than waiting until it’s fully sculpted. You can bake clay as many times as you need. A lot of sculptors bake after every work session and may ultimately make a doll 50+ times before it’s done. This way you never risk damaging more than you’re working on at the time.

      1. Thank you very much. Very helpful. I did not know you could bake it in stages. lol. That makes it much more manageable. Also I switched to Premo and covered the whole thing with aluminum foil and turned the temp down by about 25% to adjust for my hot oven and now it works great. Thanx!

        1. Excellent! Just make sure that you didn’t turn the temp down to far. Underbaking is just as much of a worry as overbaking. And if it’s underbaked you can be cracking, crumbling, breaking, and other unsavory stuff.

  10. Thanks so much for sharing your tips and tricks. I’m sure hoping that what I have learned here will help, I was ready to give up. I love covering items like altoid tins, etc, but every single one I have done has cracked and I was really losing heart for the clay. I’ve got my list all ready for when I get to town next and hopefully I will have some success. I used to be a bead maniac but my eyesight has made it tough to thread the needles so the clay came along at a good time for me and when things started cracking I felt very discouraged. I have much more hope now that I can continue on….thanks so very much!

  11. Thank you SO much for this information! I have been so bummed lately that my Premo bangles and flat beads or pendants are just crumbling! I bake 45min to 1 hr at 275 in a convection toaster oven, but didn’t have a thermometer. I’m going to the store this minute to buy one and I hope that fixes my issue! I don’t know if rebaking will give the same strength as if it had been correct the first time, but hopefully I can save some of my other detailed pieces before they crumble to bits! I’m so glad you mentioned that as an option. Thanks again for sharing your wisdom!!!

    1. Yes, it really does make a difference. And sometimes the thermometer is wrong. Also the temp doesn’t always stay stable, so still do cover so that you don’t get browning.

  12. New to polymer clay ( except using it years ago with children when conditioning by hand was a rea drawback) but with a pasta maker, guidance from your amazingly generous site and some great local tutors, having a great time now! Thanks for taking the time to research and share your findings so clearly.

  13. Hi Ginger! I’m having a little trouble measuring my creations. If I’m baking a 3D object, how do I measure it? Do I measure it vertically or horizontally, from end to end, or just the thickest part, from the middle to the edge or from edge to edge? Currently, I’ve just been guessing and baking it at a low heat for a long time, which I feel isnt very efficient. I’d love if you could help me. Thank you SO MUCH!

    1. In general, you’d want to measure the thickest part. For something that’s 2-3″ thick that seems weird though…that might mean 3 hours. But for things that thick, it’s best that they not be made from solid clay anyway. Use a foil core or an armature to reduce the amount of clay you’d use. Long, low bakes are the best for larger pieces, though. Also, you can bake in stages. Bake the core, then add more clay, and then bake that. And you only need to worry about curing the outermost layer in this case.

  14. Pingback: Cernit Doll-Making Clay — Conditioning and More | karenascofield

  15. Hi Ginger. I have found your tips so incredibly helpful. I have just sent off for a small package of clays and can’t wait to start. Looks like lots of experimenting at first! I am wondering, how long can you leave your clay before you bake/prove it – e.g. what if I need to go away for a few weeks mid-make? Jo

    1. Thanks Jo! Yes, experimenting is the best way to learn. You can leave things alone indefinitely before you bake them. The clay doesn’t get old or anything. Do make sure you cover it from dust, and don’t leave it in contact with anything absorbent. But it should be just fine when you’re ready to bake it.

  16. Thanks for this posting, Ginger!
    A few years ago, I was working in Bulgaria for several months. Yes, I had lugged clay and pasta machine across the Atlantic. In my spare time, I crafted in my hotel room, but needed to find a way to cure the pieces.
    On one fatal occasion, the hotel chef agreed to bake my pendants in his oven at 275 and did so…at 275 Centigrade. I don’t know how many hotel guests died as a result.
    On to Plan B. I then bought an electric hot water thingie from a street vendor and boiled my pieces. It make them strong enough to survive the return trip till I could get them home and into my oven for a full curing. For our art, we do what we must!

    1. What a great story! Oh yes, I’m sure that many people have run afowl of the °F/°C difference. But so frustrating to lose your work like that! Yes, we do what we must for our art. Oh yes we do.

  17. Layte Bowden Dopp

    YOU are a gift to all of us out here struggling to do better work. It is such a wonderful
    medium and It was years ago that I was into it and with all the new products associated
    with polymer now – it’s a whole new world for me.
    I thank you for every email you send. Have a wonderful Christmas….Layte

  18. Hi Ginger 🙂
    Well last week Dad and I went to the city for the day 🙂 3 hours there and back but worth the trip 🙂 I decided on impulse to buy me a toaster oven just for my clays I picked out one and Dad decided I needed the next size up cost more but I like it 🙂 now I can work on my pieces and just pop them into the oven next to me and bake while working on something else 🙂 it’s nice not having to get up and walk into the next room to bake my pieces now 🙂
    I learned it was always best to cook my pieces for longer I did this off my own bat when I first started because I did not trust the cooking times 🙂 I just went with my instincts and now after reading your article I am so glad that I did 🙂
    I had noticed some colours came out darker when baked for longer and so I have started to add white to some of them just a little and this has helped on some of my colours but not all of them 🙂 but I am learning to work my way around this problem 🙂 as for whites these I knew and have only give them an extra 10 minutes as you have pointed out too much baking changes their colour but again I found adding some white paint to the White has helped a little to retard the colour shift a little.
    Unfortunately my doves I made for the Christmas tree did not want to play and so rather than being white they are a mid-cream colour 🙂 oh well can not win them all 🙂
    Thank you for sharing your thoughts with us I know for one it has been a great help 🙂
    Have a great day 🙂

    1. That’s a very good tip about adding a touch of white to counteract the darkening of colors. It’s a tip a lot of the pros use. Thanks for reminding me about it. Enjoy your new oven. 🙂

      1. Thank you Ginger 🙂 and I am loving my new little oven I have been very busy at night watching TV and making things 🙂
        I am making two mobile phone holders for friends Christmas pressies at the moment 🙂 and with the constant mini bakes I need to do its so much faster now as I don’t have to spend 15 minutes getting out of my chair and walking to the kitchen to backe them for a few minutes so they are a little firmer to handle for the next step 🙂 (partly disabled that’s why it takes me for ever to get out of my chair 🙂 )
        All the changes in my corner of the living room is to make things easier for me 🙂 will have to take a photo after I have vacuumed first to show you my little craft corner heaven 🙂
        Thank you so much for all the handy tips you share with us all 🙂 oh and I just ordered my oven temp moninter from 2Wards Polymer Clay 🙂 I love their site and Over the Rainbow site two it’s nice to have two great web sites for clay here in the land of Oz 🙂
        Have a great Day 🙂

  19. I always find your work to be helpful, informative and well written. I really thank you for so many things – tips, etc. That my Thanksgiving – a little late!

  20. Thank you from me too. I followed your advice about the roasting pans and found some small bbq ones that fit nicely in my small oven. I always wondered how long to bake my pieces because 30 minutes never seemed enough. I have more confidence after reading this blog now, to bake longer as my pieces so far have not been baked enough. Love your blog too. I have been using PMC3 a lot lately but today have an urge to use some Souffle that I bought. So your post was quite timely. Thank you again.

    1. Yes, I’ve seen those small Weber ones for bbq’s and I’ve heard they fit perfectly in a toaster oven. No, 30 min is not enough. And lately I’m finding that Premo is needing longer than it used to. Could be my imagination. Hard to know. Have fun with your Souffle. Some day I’d like to play with metal clay…sounds like fun.

  21. Hi Ginger,
    Thanks for your great generosity of spirit in sharing all your knowledge.I have decided to purchase a toaster/convection oven(better control) with a digital temperature read out. Hopefully this will make it easier and I won’t have to constantly change the temp on my toaster oven.Thanks again.

  22. Gracias por los consejos, siempre vienen muy bien. Yo compré un horno pequeño para la arcilla y durante varias veces me coció a la misma temperatura (130º, enciendo y con el termómetro veo que llegue a esa temperatura, después cocino), lo extraño fue que después de varios meses, un día y nadie mas que yo lo toca,llegó a los 150º. Mi conclusión es de que SIEMPRE hay que estar atenta y no fiarse.. Saludos cordiales y otra vez muchas gracias.

    1. Sí, esta es una muy buena razón para cubrir la arcilla durante la cocción. Nunca se sabe cuando su horno va a funcionar mal. Sé que la gente que trabaja con arcilla todos los días y de repente su horno hace cosas extrañas, arruinando su trabajo. Me alegro de tu arcilla estaba a salvo!

  23. Hi Ginger! Thanks for this, it was very interesting.

    In your “Know your Oven” section, you said, “Be aware that the temperature dial on most ovens is wildly inaccurate”. Oh SO true! I bought an oven specially for my Polymer Clay and it took a few MONTHS in trials to get the oven temperature and my thermometer to agree with each other. I would have to turn it up a millimeter here, a millimeter there and then suddenly it would be way too high and I would have to start all over again. I don’t know if this is because all new ovens have a filament heat adjustment time, but my oven certainly did. And then it happened – suddenly the temperature stayed the same and I haven’t had to touch it for some months now.

    While some people use their cooking household ovens for Polymer Clay, I would advise buying one specially for the task because this way you don’t have to readjust the oven temperature each time.

    I bought a grill/oven on Amazon UK and of course they are available anywhere. It’s hard and laborious getting it right but worth the effort in the end.

    Happy creating to one and all :o)

    1. I wonder about the filament adjusting…that does make sense. And I agree with you about not having to adjust the temp each time. My oven is digital so I don’t worry too much. I’m glad you finally got yours “settled in” and working well. Life’s too short to have burned clay, eh?

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