How to Bake Polymer Clay: Part 3 – Tips and Tricks


Polymer clay, also called polyclay or fimo, is a modeling material that you can cure or bake at home in your regular oven. Today is a focus on Tips and Tricks for getting the best results when curing (baking) your projects. Check out the other articles, too. Part 1 was on Choosing your Oven and Part 2 was about Temperature.

Polymer Clay Baking Tips and Tricks

  • Polymer clay must be baked long enough and hot enough to get complete fusion.
  • Delicate structures need to be supported during baking, so use a bed of cornstarch or polyester fiber for this. Toilet paper or paper towels also work well.
  • When baking on tile, to keep the back of your item from being shiny, bake on a piece of copy paper or cardstock.
  • The oven’s element can be fiercely hot, causing browning even when the temperature setting is correct. Always cover your work.
  • Preheating is best as many ovens spike during the preheat cycle.
  • Boiling does not give a complete cure of polymer clay.
  • Ceramic tiles can help an oven maintain a stable temperature.
  • Make sure to read the articles on polymer clay ovenschoosing a temperature, and baking time.


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

End the confusion about baking

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!

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!


How Long Should I Bake Polymer Clay?

It’s no wonder that people are confused about this one. Here’s what various packages of polymer clay tell you about baking duration:

These are the absolute minimum times that you should use, and the recommended 10 minutes for Kato is just plain erroneous. Polymer clay becomes much stronger when it is baked longer than these minimum times. You cannot burn or damage polymer clay by baking it for a very long time, even hours, as long as the temperature is correct. Unlike food, which will burn if left too long in the oven, polymer clay will not burn if baked at the correct temperature. The limiting factor, though, is that light colors of polymer clay will darken and brown with longer times in the oven. It does not damage them, but it will easily ruin your effect, especially if you’re working with light or translucent polymer clay.

I always recommend baking at least 45 minutes per 1/4″ of thickness and even longer for thicker pieces. For optimal results, do what works for you, not what a package says.

Not sure you’ve baked your piece long enough? Read about how you can tell if your polymer clay is baked by testing the flexibility here.

Position in the Oven

When you put your polymer clay in the oven, try to center it as far from any heating element as possible. You want good air circulation around your items so that the heat can distribute evenly inside the oven. Put it on the center rack, equidistant from the elements, and keep it away from the oven’s walls. This is obviously more difficult in a toaster oven as the baking chamber is so small. But if parts of your project are too close to the heating element, it will burn.

Protecting your work from the heat

As anyone who has ever held their hand above a stove’s heating element can attest, it gets awfully toasty! Even if the overall temperature in the oven stays where you set it, every time that heating element cycles on, it glows red hot and can singe your polymer clay pieces if they’re too close. Some ovens don’t regulate this very well and the element will scorch things, quite badly at times. The best way to protect your beautiful artwork from baking disasters is to protect it and shield it from the heat by keeping it covered up.

Aluminum foil pans protect polymer clay from the heat during baking. The Blue Bottle Tree.

I use an aluminum foil cake pan, most often the 8″ x 8″ size because my 6″ ceramic tiles fit perfectly in the bottom. (Those of you outside the US will need to find the sizes that work for the materials you have where you are. In the UK, I know you can get 150mm tiles and 240mm square pans.) For larger projects I use larger pans and tiles. You could use a sheet of aluminum foil. Or a covered roasting pan. Or an upside down pan. Covering your work protects it from the heating element and it also helps keep the heat contained at a steady level inside the pan, leading to a more complete and reliable cure.

Another fantastic bonus of using a cover is that the chemical smells that come from baking polymer clay will be greatly contained. The few times that I have baked uncovered, my husband has come to me, worried, because he could smell the clay and thought it was burning! (It wasn’t.)

One other nice bonus that comes from using the foil pans is that I have a cover for my unbaked pieces in the studio. Sometimes I’ll have the pan sitting there for days until I’ve made enough pieces to bake. The cover keeps the dust and curious kitties from ruining my clay.

If you use a toaster oven and have a tiny space, you could use the tiny aluminum foil pie pans the same way that I use the larger pans.  Any pan with a lid that is oven safe could be used to protect your clay while baking. Keep your eye open for a small unpainted metal box, or even a tin. Run it through the oven by itself first to make sure it will handle the heat, though, just to make sure.

Maintaining a Constant Temperature

Convection ovens are much better at keeping a consistent temperature, but conventional and toaster ovens use a hot element, cycling on and off, to keep the space heated. The radiant heat from the element can burn your clay, as I’ve already stated, but there’s also the problem that curing of your items can be inhibited if the temperature doesn’t stay high the whole time. If your oven is one of those that gets fairly cold before the element kicks back on, it might be helpful to place ceramic tiles on the rack in the middle of the oven. This will act as what’s called a “heat sink” to help hold and evenly distribute the heat. You could also use an old pizza stone if your oven is large enough.

This is why I use a ceramic tile in the bottom of my foil pan baking system. It helps keep the temperature constant. I also use my ceramic tiles as work surfaces, if this is a new idea for you, you might want to read about how ceramic tiles are one of my most indispensable tools.

Support and Protective Material

When you place raw clay on a glazed ceramic tile and then bake it, the places where the clay touched the tile will be shiny. To prevent this, merely place your item on a piece of scrap copy paper, an index card, or a piece of card stock. Don’t worry, the paper will not burn. But make sure that it doesn’t have any printing or writing on it as the inks could transfer to your clay.

If you’re baking round beads, setting them on a flat surface is a recipe for frustration! To keep them from rolling all over the place, merely accordion fold a piece of blank copy paper and set your beads in the folds. They’ll stay in one place and they won’t have shiny spots.

baking polymer clay beads

Another method is to use a piece of polyester quilt batting. Again, it won’t burn in the oven, and it keeps your pieces from getting a shiny spot. Batting is a great tool, too, if you work with sculpture and need to support parts of your pieces during baking. Just use lots of polyester fiber fill to prop it all up.

One thing to note about using paper, though. Don’t leave your art piece on paper for very long before you bake it. You might notice an oily spot on the paper…that’s the liquid plasticizer that’s leached out of your clay. A small amount won’t hurt your clay (make sure to discard the paper afterward, though). But if excessive amounts of plasticizer are leached out, it might weaken your piece.

How to prevent browning of your clay projects

Translucent and light colors of polymer clay are very susceptible to turning brown during baking. This is not an indication of burning and is not dangerous, but it is frustrating. It’s just one of those things you have to work around and there are some things you can do to prevent, or at least minimize the problem. Before we get to those, though, make sure that you are baking at the right temperature and are covering your pieces during baking to prevent the heating element from damaging your work. Here are a few other things you can try.

Bury your Beads

Another strategy to protect your polymer clay from the heat of the oven is to bury them in baking soda (bicarbonate of soda) during baking. Other people use cornstarch or salt. To do this, just pour an oven-safe bowl of your favorite powder, dig a hole, and put your beads inside. Put the whole thing in the oven to bake. After baking, you will need to rinse the powder off the beads. Some people report that cornstarch is harder to rinse off and leaves a white residue, so you might prefer to use baking soda if that’s the case. Regardless, don’t leave the beads sitting around unbaked in the powder for very long, though, for the same reason as with the paper above. The plasticizer can possibly leache out of the beads, leaving them brittle.

If you bury polymer clay beads in cornstarch during baking, it will help protect them from browning. Article at The Blue Bottle Tree.

Experiment with Time and Temperature

Higher temperatures and longer bake times lead to more browning. So reducing the temperature or the duration of baking can solve the problem of browning. But, as I’ve discussed previously, that can also lead to weakened and underbaked projects. I suggest carefully experimenting with minimizing the baking time and temperature while at the same time monitoring the project’s strength. You need to bake long and hot enough to be fully cured and strong. Try the other strategies first, and if you still have unacceptable browning, then try experimenting with the time and temperature of baking.

Preventing Plaques and Cracks

Plaques are whitish areas that appear in the middle of a piece of polymer clay after curing. They look like they’re air bubbles but seem to happen when there was no obvious air trapped in the raw clay before baking. It’s more obvious in translucent and light colored clay. It’s been suggested that they are caused by water vapor or air collecting in the clay during curing and that they are caused by or exacerbated by sharp contrasts in temperature during baking or cooling. You will see more plaques when you’re baking too close to the heating element.

Can you bake polymer clay more than once?

A common question for those new to polymer clay is “Can you bake polymer clay more than once?” The answer is YES! There is no reason you can’t bake a piece of clay as many times as you need to. In fact, for complex pieces, it’s common to bake parts of the piece separately and then assemble and attach them after baking. It’s also perfectly fine to attach raw clay to baked clay and bake that. Sometimes it’s the only way you can get certain effects.

High Altitude Baking of Polymer Clay

If you live at a high altitude, then you already know that the laws of physics can do some strange things to your baking times and temperatures. Because baking times for food needs to be adjusted at high altitudes, many people assume this is the same for polymer clay. It is not. There is no water in polymer clay, so the air pressure differences of altitude are irrelevant.

Alternate Methods of Curing


Do not use a microwave to cure polymer clay. It’s the wrong kind of heating process. It’s not going to cause sparks or anything like that, but it will cause smoke when it burns! Read more about it in my article about it here.


For some reason, there is a controversy about using boiling water to cure polymer clay. Some people say that it works, but that just isn’t realistic. Water boils at 212°F (100°C), which is a temperature too low to cure polymer clay. You’d think that adding more heat would raise the temperature of the water, but in reality, it doesn’t. Blame physics. Now some people will say that boiling for a long time does give a complete cure for polymer clay. I am very, very skeptical of this.

However, I can conceive of why you might want to boil a polymer clay sculpture, for instance, to allow the water to support the item long enough to partially cure. This might be helpful with complex thin projections or pieces that would ordinarily be too floppy to bake without the support of the water. You would then fully bake the item at a proper temperatures in the oven. But that’s not something most of us are going to be dealing with.

Heat Gun

A heat gun is a valuable tool for working with polymer clay. You can spot cure polymer clay with a heat gun but you have to be very, very careful to keep the gun moving at all times and not get too close to the clay. Heat guns produce enough heat to scorch and burn polymer clay causing it to blister and turn black (and produce irritating fumes). Yes, I hang my head in shame here. I have done this. But as long as you’re super careful to avoid burning, you can sort of “soft cure” clay to get it to solidify. You might use this technique if using liquid clay to assemble a sculpture, for instance. But it’s not a complete cure and you would still need to fully cure your project in the oven.

Cynthia Tinapple does use a heat gun to cure her polymer in place in the wooden bowls she creates with her husband Blair Davis. But she also uses a digital thermometer to make sure the clay is actually reaching curing temperature. For most of us, this isn’t a generally reliable way of curing polymer clay.

Well that’s all I can think of. You should have a pretty good idea of how to bake polymer clay. Now go make something beautiful!

This article was Part 3 of a series on Baking Polymer Clay. Part 1 was about Choosing the Right Oven and Part 2 was about Using the Right Temperature. Next is Part 4, How Long to Bake Polymer Clay.

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191 thoughts on “How to Bake Polymer Clay: Part 3 – Tips and Tricks”

  1. Hi Ginger, thanks a lot for providing all this advice. I have a recurring issue with shiny spots on the back of my flat pieces despite using your method: ceramic tile+ blank copy paper + polymer clay piece (+ paper + ceramic tile on top to prevent bubbles – my other biggest problem). And yet every flat item has this issue. Only tiny pieces come out fine.
    I use the regular copy paper and it’s the same paper on which I work: this way I don’t risk leaving fingerprints transporting the piece from one piece of paper to another. I bake right after creating the piece. If that’s of importance, I don’t use pasta machine, so the flat pieces may be of uneven thickness. What do you think is happening? Thanks!

      1. Anna Nikolaeva

        Thanks for your reaction! I thought they must be flat on the back because of the rolling process (they lie on a flat surface when I use ). Does this mean that using pasta machine is a must to ensure the perfect flatness?
        If a piece is supposed to be flat on both sides, then using tile “sandwich” during the baking should help, but I often have a pattern on the upper side, and that’s where I get in trouble. Just wondering if I must buy the machine to resolve the issue.
        Thank you.

        1. No, you don’t need a pasta machine. But you should roll the sheet flat with a roller to make it flat. After that, place the sheet on some parchment paper, put another sheet on top, then burnish the sheet (using a fair bit of pressure) with something flat like a meat presser thingy or an espresso tamper. That will flatten the back. Peel the paper off and you’re good to go.

          Also, there’s no need to bake with a tile sandwich. It smashes your design. Avoid bubbles by carefully conditioning. Make sure you never trap air.

  2. Hi Ginger,

    I love reading your blog and really appreciate all of your helpful advice!

    I have a dilemma I was hoping you might know the answer to! I worked for hours on a thin slab (less than 1/4 inch) and baked it at 230 for 30 minutes because I use Fimo professional. Well, I’m a dummy and forgot I used premo white for a majority of the light pastel colors so it’s definitely underbaked since that requires 275. Will a second bake at the right temperature save my pieces from being brittle, or is it too late? 🙁

    1. It’s probably okay, but I don’t know for sure. As long as the background is Fimo, it should be fine. If the Premo is the decorative part, it should be well supported.

  3. Hi Ginger,

    I really want to try your technique, but I get worried about putting all these items (printer paper, binder clips, and ceramic tile) in my oven that I also cook food in. Do you also cook food in the oven you cook your clay in or should I try and keep these separate?

  4. Hi there,
    I am trying to bake a wine size bottle covered in polymer clay. My question is – as I will need to lay the bottle down to bake (because of size), if I lay it on something (cotton wool etc.) will this stick to the bottle? If I don’t lay it on something then won’t the shape alter during baking (giving a flat area where the bottle is laying on a baking tray?
    Thank you,

    1. Yes, you need to lay something down, preferably something curved to match the bottle so that the weight of the bottle doesn’t make a flat spot. Yes, what your using might stick (or worse, leave a texture). Lots of people use cornstarch. Or baking soda. Or cotton quilt batting.

  5. I am new to working with polymer clay. I need to create a base/frame, and then create pieces that fit into it. (Imagine a 1/4-inch thick map with an indentation for a riverbed, then add the river that must fit the riverbed exactly, and be removable.) If I create and bake the base/frame, then (after it cools) press clay into the “riverbed” and bake the whole thing again, will the “river” fuse to the “riverbed”, or will it be removable? (I am afraid I will alter the shape if I remove it to bake it separately, and then it will not fit.)
    Thank you!

  6. Great information Ginger, can you make a “tent” from foil to bake it instead of baking pans?

  7. I used to work with polymer clay back in the 90’s and I’m thinking about getting back into it. I’d never heard of boiling the clay before, but it got me thinking: If temperature is the important aspect for curing the clay, then what about using a pressure cooker? Those can hit 250 degrees and can hold that sort of temperature without fluctuation for quite a while. Not all of the clays can cure at that temperature, but a few can.

  8. Hello Ginger! I am new to polymer clay, and was wondering if, when baking a sculpture larger than 1/4″ thick(I have made an owl about 2″ thick, but I fear hollowing it out and giving it a aluminum foil core will damage the sculpture), how the best way to bake it would be without cracking it. Thanks for your help!

    1. Oh no, don’t hollow it out. You really need to start with a foil core, not add one later. The only thing to do with this one is to just go ahead and bake it. It might crack, yes, but hopefully if it does, you can fill in the cracks and bake again.

  9. My polymer clay pieces puff up or curl under. What am I doing wrong I heat oven to 275 and am using premo clay on parchment paper on cookie sheet I covered with an aluminum pie pan but then it all burned!!

  10. Hi Ginger. Thankyou for this amazing information. I am currently having issues with a rough surface on the bottom of my baked polymer clay. I use 2 tiles with baking paper in between and really focus on smoothing my pieces out before curing however the underside of my work looks like the surface of the moon. Any advice?

  11. I’m making a couple of dinosaurs for a cake top, with long necks. Will they slump/fall down during the baking process? Should I support them so they stay upright, and if so, with what?

  12. Linda chiasson

    I have not been able to find an oven thermometer locally. Will a cooking thermometer work? Ty

    1. I had to order mine online. You need to be able to leave the thermometer in the oven and read it through the door (or with a cable and remote sensor). The probe style for measuring meat also works.

  13. Hi! I would like to ask. What if I make an earrings this evening but plan to bake it tomorrow? Will there be a difference on the clay’s texture or the clay itself? Thank you!

  14. Hi, Ginger …so glad I found you! I just recently got back into sculpting. Im loving it. I made a sitting, straddled elf for my mom. It sits 8″ tall 8″ deep and legs about 10″ wide apart. Ive spent a good two or three weeks on it. I want to use my new pizza stone with parchment paper, thats where he sits at the moment. I wish I wouldve used an armature so his middle werent as thick. But too late now! Ive forgotten such things after all these years. Anyway, should I slip him into the oven (already on the stone with parchment paper) while it preheats? Preheating the stone is reccomended by manufacturer to prevent breakage/shock which may also prevent the same for my sculpture, yes?
    This probably going to need a couple hours his center is 2.5 ” around and head is 2″
    Thanks in advance for your help.
    God bless you.
    Love, Joy

  15. Would parchment paper work just as well as copy paper? I am new to polymer clay and just trying to figure out different options. This has been a wonderful help and is an awesome article. Thank you so much for all of the information.

      1. Wonderful! Thank you. I got a big box of parchment paper years ago that my mother and I have been using for baking over the years. I still have a ton of it so that was why I was asking. Thank you for all of your helpful articles. It is making this new hobby of mine a whole lot less stressful.

          1. It can, but because it’s unglazed ceramic the stone will absorb plasticizer and oils from the polymer clay. Also, it’s quite large and it will take a long time to heat up after putting it in the oven. Make sure to begin timing only after the temperature has returned to the correct level.

  16. Hi Ginger

    I’m just playing around with polymer clay and this post is very helpful.
    I was and wondering what kind of clay tile you put in your pan?
    Is it like a floor tile a backsplash tile or something for a grill or something specific for clay drying? Sorry I tend to overthink things but I want to get it right.

    Again thank you for this helpful post.

  17. Best clay for small pendants? Will Fimo soft work? If we create small holes with end of a paintbrush or straw, will the holes stay open.
    We are doing a library program – making small pendants to be used as essential oil diffusers (once baked, they will add a ribbon and a bead or two, then take home to put a drop or two of essential oil for a wearable diffuser).
    Appreciate your very clear instructions on baking!

    1. Polymer clay will not absorb the oil, so it would just run out. A better way is to embed a small glass vial inside the clay, then stuff a cotton ball inside the glass. Apply the oil to the cotton.

    2. We are planning to make earrings with polymer clay. We are going to add a lava stone bead to the earring which we can add the essential oils to. if you have any other tips about this, I would love to hear them.

  18. I need help. I’m just starting and the experimenting is driving me crazy. Using my oven thermometer, I can get to 275 degrees accurately. But just for my own info, I put the thermometer inside my two pans (metal foil, with one covering) and the temp inside was much lower. Do I get the oven temp to register much higher to get it right inside the pans?

    1. No, that would cause the temp inside to (eventually) get too hot. The problem is that heat takes a long time to get up to the correct temperature inside the pans. So the solution is to bake longer.

  19. I would honestly test the various methods before blindly dismissing them as ineffective or ‘wrong’. It doesn’t sound like you’ve actually tested any other method of curing the clay to see (for yourself) how it stands up to the method of oven baking you use.

    Preferring a method is wonderful, championing it is wonderful. The amount of experience you have with using an oven (presumably an electric?) has given you the ability to share a lot of wonderful tips and hints. However, blindly cutting down the other methods with no prior experience with them is… foolish.

    1. Yes, thankfully my own experience, understanding of physics and polymer chemistry, personal consultation with polymer clay company chemists and representatives, discussion with seasoned experts in the clay community, and experimentation back up my position. There are many ways to cure polymer clay, but ultimately they all come down to baking the clay hot enough and long enough to allow for complete fusion of the clay mass while also avoiding scorching and color change. Any method which achieves this goal is a valid method. Microwaving and boiling do not achieve this goal.

  20. Thank you very much Ginger – very interesting and helpful information.
    I looked for instructions on the Staedtler website but didn’t find it of much use.

  21. Hi. Love all your detailed information. Thankyou

    I am baking peices about 2-3 mm think for 1hr. As they need to be flat i bake them between 2 tiles and in between 2x peices of paper. I use a thermometer and bake once pre heated at 130 celcius fan forced.

    1. Do i still need to cover my already sandwiched tiles with trays?

    2. I am mising brands of clays. Mostly premo and fimo and find vast colour shifts. Even in colours that normally wouldnt.

    3. I am confused about the breakability of clay fimo and premo. When cold yes they seem strong untill i actively try to break it. From what i have read i should be able to bend almost in half when cold?


    1. There are several things going on here. One…when you bake between tiles, it takes a long time for the temperature to get hot enough to cure the clay. So you’re effectively baking for a shorter time period than you think. Also, your oven may not be correct. Most ovens have no relationship between the dial and reality. Use a thermometer and adjust accordingly. You are correct that your clay should not break when bent. Your temp is not high enough and the clay is not staying at that temp long enough. No, you don’t need to add a tent to this. All tenting does is shield the clay from being browned by the oven’s element. In your case the ceramic tile is doing it already. As for color change…MANY colors get darker when baked. This is normal and just a characteristic of that color. It’s not a symptom of a baking issue.

  22. Hi Ginger,
    Thanks for the great information. I design dolls. The temperature in my oven is not constant. It can vary up and down 25-50 degrees during a bake. I’m using Fimo clay and can never get it to stay at 265 degrees for 30 minutes. Is it alright for the temperature to vary during the bake? Is there a safe range which will still cure the clay.
    Help! This is driving me crazy!

    1. I think this is perfectly normal. NO oven stays steady. This is why it’s so important to sort of average it (aim for 265°F) and baking longer, often an hour or more. And make sure to cover your work to help protect against the clay burning while the element gets hot. You’ll know you’ve baked long enough if you can bend the result without breaking. You should not be able to break a piece of Fimo Professional in your bare hands if it’s properly baked.

  23. Dear Ginger – I’m helping Haitian women launch a coffee bean jewelry business– so darkened beans or lighter beans are desirable (I’m not too worried about the baking part). I only need 2 clay colors: medium-dark brown and a dark brown. Any suggestions?

    Next, how long can I wait from making beads to baking beads? Is it ideal to bake the same day as beads are made? Or even shorter than that like within a couple of hours?

    One complication: we’re making the jewelry in Haiti to help employ impoverished women & it’s HOT there.

    1. You can make and bake the beads right away. There’s no waiting time necessary (and you can wait if you need to). I would use Premo or possibly Kato. You’ll most likely need to mix a custom color for each of the browns. The heat won’t be a problem. Many people fear that hot climates affect the clay, but Haiti’s not as hot as an oven (though I’m sure it feels like it at times!) If anything, the heat will make the clay easier to work with.

  24. When you rebake a polymer clay piece with a new layer, do you bake it for the same amount of time you did the first time/first bake? I’m a little new to polymer clay, so I’ve been trying to do some research on it.

    1. As long as the oven is set to the correct temperature (use a thermometer to make sure), you can’t overbake your clay. So don’t overthink the bake times. It needs to bake long enough for the entire mass to warm up enough so that the new clay will cure. To make things simple, I keep the layer of new clay less than 1/4″ and then bake about 45 minutes. (But then I bake everything for 45 minutes to an hour.)

  25. Are you able to bake polymer clay stuffed with aluminum foil? My students are making creatures and dolls that are similar to the size of an adult hand.

    1. Yes, in fact this is the most common way to create a base form for sculptures and larger items. It’s never a good idea to create anything with polymer clay much thicker than about 1/4″ in one baking cycle. Compressed aluminum foil is also a much cheaper way of filling up the bulk.

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