Avoid These 10 Sculpey Mistakes (and other clays, too!)

When I started working with polymer clay, I made a lot of mistakes. (I still do, by the way.) But experience has taught me a few things and here are some mistakes that I no longer make. (These tips apply to all brands of polymer clay, not just Sculpey. Read on if you use any oven-bake clay brand!) Nobody likes to have their work break, burn, melt, get sticky, or fall apart. Ruined projects are disappointing, but it’s even worse when we’ve given things as gifts or sold them to customers only to realize they’re falling apart over time. So whether you’re new to the world of Sculpey, Fimo, and polymer clay or whether you’re an old pro, it doesn’t hurt to take a moment to check these out. Avoid these 10 Sculpey mistakes and spend more time enjoying your work with polymer clay.

1. Using Weak Polymer Clay for Thin Pieces

Underbaked polymer clay will crumble. How long to bake polymer clay? Read more at The Blue Bottle Tree.It is so sad to work hard creating something that breaks when it’s worn or used. It’s even more horrifying to realize that you’ve sold something that is made from weak clay and won’t be durable. Not all polymer clay brands are created equal and each has its uses and purposes. For making things that are thin or have areas that are thinner than 1/4″ (6mm), make sure that you’re using a strong clay such as Premo, Fimo, Pardo, Kato, Cernit, or Souffle. Sculpey III, Original Sculpey, Super Sculpey, and Bake Shop are all quite brittle after baking and should not be used, unsupported, in any area thinner than 1/4″ (6mm). These weaker brands do have their uses, however, so save them for other projects. Here’s more about choosing the best brand of polymer clay for your project.

The stronger brands of polymer clay are durable enough that you cannot break them with your hands, even when used as thin as 1/16″ (1.5 mm). Of course to have this kind of durability the clay must be properly baked, which leads us to the next point.

2. Underbaking Polymer Clay

Polymer clay is made from PVC powder, plasticizers, binders and fillers, lubricant, and pigments. As the temperature increases during curing, the powdered PVC softens in the plasticizer and the particles begin to absorb the plasticizer. Optimally, the particles will eventually fully fuse together and form a solid mass of plastic. If polymer clay is underbaked, the fusion will not be complete and the resulting clay mass will be weak. Underbaked clay is not only less flexible, it is susceptible to breaking and crumbling. Underbaked polymer clay can also have excess free plasticizer that can lead to cure inhibition in paints and glues, causing them to remain soft and/or sticky.

To properly bake polymer clay, you must consider both time and temperature. The temperature on the package is a guideline, and you do have some leeway. But you really do need to bake at a sufficient temperature for at least as long as the time stated on the package. Most ovens are inaccurate and it’s important to use a separate oven thermometer to know what temperature your oven actually is. (I like this inexpensive digital probe thermometer, but there are many others.) In the real world, even accurate ovens fluctuate during the baking cycle (and when you open the door). It’s therefore best to bake quite a bit longer than the label suggests to make up for this.

Use oven thermometers to verify the temperature of your oven when baking polymer clay. Most ovens lie.
I use two digital probe thermometers to verify exactly what temperature my oven is during baking. I’ve been quite surprised to see that my oven’s dial is often off by 40°F or more.

Polymer clay should be baked for at least 30 minutes for each 1/4″ of thickness. This means that a 1″ thick bead will need to be baked for two hours. Yes, this is correct. If your oven is truly baking at the correct temperature, your clay will not burn. Lighter colors may, however, discolor, so it is always better to do multiple bakings of thinner layers. Want to learn more? Here’s my series on baking polymer clay that gives more info about choosing an oven, baking temperatures, and knowing if you’ve baked your clay long enough.

Burned and blistered polymer clay is a result of using an oven that heats to the wrong temperature. Learn more Sculpey Mistakes to Avoid at The Blue Bottle Tree.

3. Burning Polymer Clay

Let me be very clear. Polymer clay does not burn unless it reaches temperatures near 350°F (176°C). (Fimo is a bit more sensitive.) If your project actually turns black and bubbles, then your oven is way too hot! As already state, ovens can be wildly inaccurate. When the oven’s heating element cycles on and off, the heat radiating from it can be tremendous. If your project is close to the element, your thermometer could be reading the correct temperature but your project could still bubble and blacken. If you have burned polymer clay, you need to address your oven, not your baking times.

Many people assume that baking longer times at lower temperature settings will solve this problem. It’s common to read recommendations in forums to set your oven to, for instance, 215°F (100°C) and bake for an hour or so. Will this work? Well, it might work for a specific person because they’re compensating for an incorrect oven. What they think is 215°F might actually be 275°F in their oven. But when others follow this temperature advice, they end up with fragile, brittle, underbaked clay.

Light colored or translucent polymer clay will commonly discolor and darken during baking. This is not the same thing as burning. To prevent this, first make sure that your oven truly is baking at the correct temperature. Then cover your pieces to prevent the oven’s element from toasting your polymer clay project. For more info on covering clay and preventing browning, see my article on Tips and Tricks for Baking Polymer Clay.

4. Using Nail Polish as a Polymer Clay Glaze

Are you making these 10 Sculpey Mistakes? Learn more at The Blue Bottle Tree.It’s very common to see polymer clay projects, especially on craft blogs, that recommend using nail polish as a glaze or gloss finish on polymer clay. It’s convenient, it’s simple, and seems like such a good idea. Except that it’s not. As many, many people have found out, nail polish on polymer clay will very often turn sticky and goopy over time. Not all nail polishes are bad. Some work just fine. But there are thousands of brands of nail polish around the world and there is really no way of knowing which ones will work on which brands of polymer clay. Don’t risk it. Use a proper polymer clay sealer. If you need to use one at all. Yes, that’s right. You don’t actually NEED to seal polymer clay. Read more and learn which sealers are the best to use when you do want to use one.

5. Using a Spray Varnish on Polymer Clay

Do not use Krylon Crystal Clear Glaze on polymer clay because it will turn sticky over time.

It also seems like such a good idea to buy a can of spray varnish and give all your newly made Sculpey creatures a nice glossy coat of spray varnish. So simple and so easy. Except that the varnish never dries. There are very few spray varnishes that are compatible with polymer clay. And what works with one brand of clay won’t work with another. I tested many brands of spray sealer on polymer clay and only found two brands that consistently works with all brands of clay.

What if you’ve used a spray sealer and now your charms are sticky? Can they be saved? In some cases, yes. I found that 91% isopropyl alcohol removed most sticky spray sealers. It’s worth a try.

6. Storing Polymer Clay Open to the Air

Store polymer clay in airtight, protected containers for best protection and longest life.Years ago, one of the best things about polymer clay was its shelf-life. You could stock up and as long as you stored it away from heat, the clay would be ready for you to use anytime you wished. It never dried out and would stay fresh and workable for years. Decades even. I have 15-year-old packages of clay that are as workable as the day I bought them. But in 2008, everything changed as the manufacturers changed the formula used in polymer clay. Nowadays, we find that clay will get stiffer over time as it “ages” on the shelf. Some brands and some colors within a brand seem to be particularly susceptible to this issue, namely translucent and metallic colors within the Premo and Fimo lines.

Because of this, it really does seem that clay stores better when kept air tight. I keep opened bricks in a Ziploc sandwich bag and then store those and the unopened bricks in one of those plastic shoeboxes with a lid. I also make sure that I use my clay as soon as possible and don’t buy more than I can use up in a reasonable time. Polymer clay changes consistency over time and a bar of clay that is almost “wet” and mushy-soft when you buy it can be dry and crumbly a year later.

Polymer clay stored open to the air, or loosely thrown into a bin will collect dust, airborne dirt and fur, and fibers from your clothing and environment. Here’s more info about dealing with lint, dust, and dirt in your clay.

7. Not Washing Your Hands Before Working With Clay

Dirty hands make working with light colored polymer clay difficult.Related to the dust issue is the one of making sure that your hands are clean before working with polymer clay. Even when you think your hands are clean…they’re not. And when working light colors such as white or yellow, or translucent, dirt that’s invisible on your hands can end up in your clay, giving your work dirty streaks. Even the blue residue from wearing blue jeans will coat your hands and show up on light-colored clay. So before working with polymer clay, wash your hands well, and don’t forget to clean under your fingernails.

Another trick is to have a ball of scrap translucent clay at your work desk. Roll this clay between your hands before working. It will pick up any loose skin bits, fiber, dirt, and dust. It’s also a great trick to do when switching from working with a dark color to a light one. When the clay gets too junk-filled, just toss it and make a new one.

8. Buying Too Many Tools…At First

It’s all too common for a newbie to find out about polymer clay and buy everything in the clay aisle at the craft store, assuming that it’s all required for working with polymer clay. Not only can this be very expensive, but you really don’t need most of the tools you’ll see for sale there. Start with some basics, then add more as your experience grows and you have a better idea of what you like to make.

There are plenty of polymer clay tools out there, and you want to leave enough money (and space) so that you can buy the things that will bring you the most enjoyment. So, what are the essentials? Here’s what I recommend to buy for your Polymer Clay Starter Kit. And when you do start buying tools, you can often find them quite cheaply when you start looking in creative places. Here’s more about finding cheap polymer clay tools.

9. Embedding Eyepins Without a Kink

When you make polymer clay pendants and charms, you’ll want to include a hanging loop. A lot of clayers take a commonly available jewelry eyepin, cut it to length, and insert it into the raw clay. But after baking, the straight wire of the eyepin readily pulls out of the clay. Some people glue the pin and push it back into the baked clay. That will often hold, but not always.

A better way is to create a small kink in the end of the eyepin, before you embed it into the raw clay. This way it cannot pull out after baking. Here’s an example of what I mean:

Always put a kink or bend in your eyepin before inserting it into polymer clay. Avoid these 10 Sculpey Mistakes.

10. Using the Wrong Glue with Polymer Clay

Superglue is magical and it can be an incredible glue in the right circumstance. But it’s not the best glue for polymer clay. At least not the usual inexpensive superglue that we all know and love/hate because the cap gets glued on (so frustrating). It is a very brittle glue and polymer clay is flexible, so when the clay flexes, the hardened glue will pop right off and the bond fails. It’s better to use a gel version such as Loctite Gel Contol or a higher end version such as Lisa Pavelka’s PolyBonder.

Cheap super glue is one of several popular glues that don't work well for polymer clay. Avoid these 10 Sculpey Mistakes, read more at The Blue Bottle Tree.

Another often recommended glue, especially for jewelry use, is E6000. While it can be a very good glue for some uses, it does tend to remain gummy never and fully harden on polymer clay. Many people DO have good results, but many others do not. I suspect the issue lies with the brand of polymer clay or perhaps the age of the E6000. But don’t be surprised if you find that this glue fails for you.

It’s always better to use a physical bond or a baked bond to glue polymer clay to itself or to glue metal to polymer. For more specific recommendation and glue strategies, visit my article What’s The Best Glue for Polymer Clay.

81 thoughts on “Avoid These 10 Sculpey Mistakes (and other clays, too!)”

  1. Great article, Ginger! I need to save this one. BTW, I am number 8 on the list! And thanks for explaining why my clay doesn’t seem to last as long. I will have to buy in smaller quantities now. I’m interested in this Liquid Fusion that can double as resin, too.

    1. I did learn this one the hard way. I had a couple of pounds of hard, crumbly Premo white trans to deal with. I eventually used it all up, but it wasn’t fun.

  2. I work with kiln fired clay and do pottery sculpture and clay pictures. I have found that polymer clay is much better at small detail and would like to do a polymer clay picture(about A4 size) of a steam engine but what would be the best thing to use as a base, it would cost far too much to make it of the polymer clay. I’m assuming I would have to make the details of the picture,bake it and then glue on to the base. I would be grateful for any help you can give.
    Thank you Doris.

    1. You could do it that way. Or you could create it on a solid base of another sort. Some people use wood or MDF. Or glass or ceramic tile. Or you could create it in a mosaic form by glueing baked bits onto a substrate. There are many ways to go with this. I would suggest to try things on a small-scale basis and experiment to see what gives you the best effect you want. Making large spans of pure polymer is impractical, btw, because it will bend and bow. Baked polymer clay is vinyl, so it’s not terribly rigid. Good luck!

  3. Ginger, as always love your articles, but I have a question on baking time and temperature. I heard this year at a retreat, and I can’t remember from who, that you must bake your clay 1/4″ per half hour the first time you put it in the oven. The person said that if the plasticizers and polymer powders don’t get fully formed into polymer chains the first time the clay bakes that baking it for shorter times a number of times does not make it stronger and that the fusing that needs to happen between the ingredients will never be completed. Since you seem to have many sources of knowledge, do you have any knowledge if this is true or not? The reason I ask, is that at our guild meetings we do demos and bake the clay items we get done just enough to harden them so we can get them home safely, under the above scenario, this would mean our pieces would be ruined and not fine if we put them in the oven and “finish” baking them later. Thank you.

    1. I have heard that as well, likely from the same source. I agree and disagree with it. One thing, polymer clay doesn’t “polymerize into chains” when it cures, so that part is suspect. but I do think that the fusion isn’t going to be as strong if it’s partly cured and then finished later. That does make sense to me. But it doesn’t mean your clay is ruined. Doing a partial bake and then finishing later DOES result in stronger results than just the pre-bake would, so obviously there is more fusion going on with a second bake. Until both situations are tested, I’m just going on my gut feelings and assumptions. I would think that a full, long bake is always preferable to two bakes. However, just to make things more confusing, when clay is baked many, many times (like for complex sculptures) it does get stronger and stronger.

      I didn’t really add much clarity, did I? Sorry!

      1. If you ever do experiments on this, I would be very interested in the results. I make little sneakers in multiple steps. So I also like to bake just long enough to make it easier to add the next layer of clay and then bake longer once everything is put together.

  4. Another great blog, Ginger. Hadn’t realized the clay composition change affected the shelf life – good to know! AMR

  5. Flo :::Talismans

    Thank you Ginger ! Essential for beginners and for advanced your answer to Jeanne about baking is very interesting !

  6. Hi Ginger, As always, a great post! I wanted to ask about item 2 and the digital probe thermometer. I was under the impression that you have to have the probe inserted in the item. I think I tested mine and it did not work just lying in the oven. Can you clarify how you use this type of thermometer. Thanks!

    1. I had the same observation at first. I tried just putting one probe in the oven on the rack and it fluctuated so wildly that I assumed being in the air was the trouble. So I made a clay sleeve for it. Same thing happened, only with more delay. Only when I used a tile on the bottom rack, then used a tray, then covered the whole setup and used the convection feature did it finally stabilize and stay the same temperature. And both thermometers read the same now. (They don’t if I turn off the convection.) And I also verified with a separate infrared thermometer gun, too. I’ll write this all up someday. It took me quite a while to get a setup that worked. But no, the air vs contact didn’t seem to matter. It fluctuated in air because the air really was changing temp rapidly. Ovens really do fluctuate like mad if you don’t cover it and make a little “cocoon”. Luckily, small fluctuations don’t matter much as clay can handle a fair bit of higher temps. But it also explains why some people have so much trouble with burning if their overs really are going that wild.

      1. Thanks for the info Ginger. I look forward to your more detailed write-up on this. I had heard about using a probe thermometer from someone else and bought the thermometer, but without these details you get a disappointing result!

      2. O my, i am glad to have found your information!
        i am new to the polymer scene, an idea born due to my hobby of fairy gardening.
        Bought the sculpty… shaped my minis, popped them in my clay oven set the timer, and in 3.6 seconds… ON FIRE!
        LOL. 2nd attempt soon to follow.

  7. As usual, Ginger, a remarkable post! Thank you! I didn’t learn anything new this time, but refreshers on what I’ve learned previously are always a pleasure and necessity, since I forget so much! 🙂

  8. Thanks for all the tips, although I had read most of these from your other more extensive posts, it is a great reminder of all things I must NOT do now that I am trying out my new polymer clay kits that finally arrived. I have however found myself guilty of committing sin number 8, like I guess others have, ah well, I will do my best to get around to use everything I bought and not feel too bad about it.

    Ginger, I wanted to ask you something I have not been able to find. I am fascinated by tutorials that show wrapping polymer clay around another object and baking them together to fuse them in one artistic piece. I have seen that you can do this with glass and with wood objects and they should not burn. However I am afraid to do so since I do have an experience of one of my friends putting a glass container in the oven to make a lasagna and the thing cracking all the way down the middle. May I suggest that it would be a great post if you could explain to us newbies exactly what materials can we join to our polymer clay creations and which ones should we not use because they can melt? I find loads of tutorials about cooking polymer clay in the oven but I can’t find one that explains what I ask. Also a bit confused about what jewels can you put in the polymer clay and bake and which ones can melt. I have seen a lot of artists using aluminum drink cans to make bangles, seems that can’t melt either but can we integrate it into a jewellery polymer clay piece?. Thank you so much.

    1. You make a good point in that it’s not automatic for people to know what can be baked and what can’t. In general, all glass, metal, paper, wood, stone, gemstones, and ceramic can be baked in polymer clay. None of those will melt, burn, or become ruined by the low temperatures that polymer clay bakes at. Your memory of a lasagna dish breaking was due to thermal stresses within the dish itself and was a manufacturing defect. While it can happen, especially if a pyrex dish has been damaged, it’s not common and not something you should generally be worried about when working with polymer. The only thing that can’t be baked is some plastic. (Not all…some plastic bakes just fine.) Many plastic beads and “stones” can melt or warp when baked inside of clay, so it’s usually best to avoid those or at least run some experiments. I’ll put it on my list of things to write about, though. It’s a good thing to share. Thanks!

      1. Hi Ginger, I had a similar experience of oven cracking with Pyrex. I was told that the composition of the glass changed after circa 1987, resulting in a weaker structure. The old Pyrex from the 1960’s and 70’s works just fine and can take stress. There are all sorts of product advisories accompanying Pyrex today, like “cool the pan with a towel under it–don’t put it directly on a hard surface or a stove straight out of the oven, allow to come to room temp before baking.” I am fairly certain that all of these advisories are because of the change in composition.

        I do have a question about the pink Sculpy. I forget the exact name, but it allows for fine detail work. My instructor is advising me to coat it with Shellac after baking. I would like to know if that’s a good finish. I plan to paint on it with acrylics also and don’t know what coating would allow for this. Do you have advice? Can you email me? Thanks, Pat

        1. Many people seem to think that polymer needs to be sealed and “shellac” is a term that many people use for varnish. I wouldn’t use shellac, the real stuff. Polymer does not need a varnish at all. Just paint on the Super Sculpey after baking, it will be just fine. If you feel it needs to be shinier or you want to have a varnish over that, you can use most water-based varnishes. I like to use Varathane polyurethane.

  9. Hi Ginger,

    I’ve got a quick question and it might be a dumb one. Can I use an acrylic latex paint that I’ve used for painting the walls of my house on polymer clay? Will it deteriorate the clay, like you’ve discussed nail polish and spray paint does?

    Thanks,
    Catherine

    1. It won’t deteriorate the clay. But it might not be as durable as you’d like or it might remain sticky instead of curing completely. But most likely it will work just fine.

  10. Do you have any recommendations on glue that can bind resin onto polymer clay? Someone suggested Liquid Fusion. Do you have any experience with Liquid Fusion, and do you know if it’ll bond resin to clay? I plan to bake the clay first, and then try to bond the resin onto it, after it cools down. Would Liquid Fusion be okay, or could you recommend something else? I also need suggestions on a glue to bond polymer clay to a metal alloy, as well. And I’ve heard Liquid Fusion would be good for that… But what about about the resin and polymer clay? Please help 🙂

    1. Yes, I have used Liquid Fusion. It works nicely on polymer clay. Though, it don’t know how it works on resin. What kind of resin do you mean? Epoxy resin (such as Envirotex Lite) is often used directly on polymer clay as a sealer coating. There’s a fair bit to know about using glues with polymer clay. Have a look at my article on glues here.

      1. I’m really not sure what type of resin it is. They’re some type of resin charms that I bought off eBay, but they didn’t specify what type of resin was used to make them 🙁 I’ll give Liquid Fusion a go, and see how well it works. I normally use E6000 glue, for my projects, but many people have mentioned that it doesn’t work very well with polymer clay, so I’m trying to find other glues that might work. Thank you for your help 🙂

        – Stephanie

  11. I just joined your newsletters today and they are great! Oh, if I had only known about your blog years ago! 🙂 Anyhooo … I stopped claying (is that a word) years ago after turning to photography, then last month I was digging around in my piles of craft stuff, and found a drawer full of Sculpey and Femo clays I had since 2004!!! Most of the clay is very usable, but I have some white clay (Don’t know the brand) that is flaky and crumbly after putting it through a pasta machine. I was going to toss it, then an idea popped into my brain cell, and I made an animal shape out of the clay. It looks like fur. My question is … FINALLY … Can I still bake it? And should it be baked differently since it is crumbly and flacky?

    1. Welcome Shannon! Yes, you can bake it. Because it’s crumbly and flaky, there’s a chance that the flaky bits might be weaker than normal clay and will continue to flake off a bit after baking. Not a lot, but it’s a possibility. Regardless, it sounds like a great idea and a great way to use up the old clay. Welcome back to claying! (Yes, it’s a word in my book!)

  12. hi there! this is great 🙂 about the eyepin having a kink, how do we insert that eyepin without ruining the sculpted clay?? and I think it’s hard to work with your clay if it’s inserted before actually molding the clay 🙁 any tips on inserting the eyepin after sculpting? 🙂

    1. You’ll have some distortion. But you can usually insert it and then repair the damage right around the pin with sculpting tools. Also, instead of using a loop or large kink, you can just bend the wire into an L shape. Insert the wire end and then tilt your hand as the kink in the L goes in…you should only have a tiny hole right around the wire.

  13. Hello,
    I agree with every kind of mistakes that you’ve described . In the other hand I glaze my first polymer clay of nail polish, and I understand, why people doing this. I know that post is about “miskate”, but maybe you can help me. My problem is: I use Fimo liquide and soft pastel to create a topping for example: ice cream . I do not bake my work right away but few days later. After a few hours later the topping is run down, because is to smooth. When I add more soft pastel it still the some. Do you know what I can do whit this? I try many things, but i can found the solution. Lots of kisses.

    1. Hi Diane, I’m sorry you’ve had this happen. Very frustrating. It sounds like what you have is not actually polymer clay. Modeling clay (plastaline) looks very similar to polymer clay and since it’s sold in the same section in the store, it’s very easy to grab the wrong package. This can also happen when we inherit craft supplies from others. We see a block of un-labelled clay and we assume polymer, but often it’s not!

  14. Can you help? I’ve 6 completed sculptures, each about 6 inches high, very detailed, took me years… I’ve not baked any of them yet, they’re very hard now and covered in dust. I want to bake them but I’m worried some chemical changes have taken place which will cause them to crack or crumble. Any advice most welcome

    1. There are no chemical changes when polymer clay sits for a long time. It does, however, become “unconditioned”. That usually only matters when you need to re-work an area. To remove the dust on your unbaked sculptures, try wiping them with a q-tip dipped in alcohol. Depending on how detailed your sculptures are, this can be quite effective. Be careful, though, as the alcohol will dissolve the clay, and fine detail could be lost. In the future, bake the sculpture after each stage of sculpting. You can bake polymer clay over and over again. As long as your temp is correct, it won’t harm the clay.

  15. Hola! Will polymer (or oven-baked , however you say it ) clay break if you drill a hole into it ! Please reply asap!!!

    1. It would depend completely on the brand of clay you use, how thick it is, how big the drill bit is, and how well it’s cured. A 1/4″ thick piece of Sculpey (Original Sculpey, Super Sculpey, Sculpey III) would mostly likely crack if you drilled through it. But a well-cured piece of Fimo Professional, Cernit, or Kato would likely hold up quite well. Do make sure you cure a long time, though, and at the correct temperature.

    2. Any success with drilling? I’m interested in holes in some premo pieces for jewelry wiring to go through and have small drill bits, but would rather bake before making the holes. Would love to hear your experience with drilling if you tried it.

    1. You can’t make polymer clay at home. Those recipes are for an air-dry clay called “cold porcelain”. Like any modelling clay, there are some things that are similar. But it’s a very different material and you can’t use it to do most of the things you see people doing with polymer clay.

  16. Can anyone tell me why my clay breaks if I put an eye pin in it while baking? It ALWAYS breaks if I do this and ruins the piece. Normally I remember and add the eye pin after but sometimes I add a detail to my piece and forget about the eye pin which means my piece gets completely ruined. 🙁

    Also, lately my clay doesn’t seem to want to stick to itself. I make necklaces with tiny details and the details ALWAYS fall off and I don’t know why!! I am so nervous about selling my pieces anymore because of this. I have to glue the pieces back on after baking just to make sure the bonds are secure.

    1. During baking? Do you mean after? If you do this, you’ll have to drill a hole for the eye pin to go into. The clay shouldn’t break, but you do need to use a strong brand of clay (not Sculpey III and do bake hot enough and long enough (at least an hour at 275°F).

      It sounds like you need to be using a dab of liquid clay when you join the details to the main clay. Then bake. This way they won’t fall off. Underbaked clay will also tend to break apart more easily.

      1. Actually I meant before baking. I have seen SO many charm artists put eye pins in their pieces before baking so I figured it would be okay to bake the clay with the eye pin in but like I said when I do this the piece breaks. Anyway, it’s not a big deal since I usually add them after. I just had a couple instances where I accidentally forgot the eye pin was in the item and I added a detail or fixed a problem and rebaked the piece, forgetting to take the pin out.

        Also, I think I may have figured out the problem with the breaking clay and pieces not joining correctly. Thank you!

        One more thing… anyone ever have air bubbles between their piece and the armature (if you use a foil+tape armature)??? Another problem I have on occassion. It’s not a matter of conditioning the clay correctly either since the air pocket develops between the clay and the armature. Not sure if there’s a solution to this but figured I would ask the experts. 🙂

        1. Air bubbles are always an issue when creating with polymer clay. You just have to be diligent in preventing them. It’s also one of the reasons why people create and armature, cover it with clay, then bake it before adding the actual sculpture part. This way the air bubbles, if they pop up, can be smoothed back down without ruining your final piece. Multiple bakes are sculptor’s best friend.

          1. This is an interesting idea. I always found it hard to cover baked clay with unbaked but I will try this with my next piece because it’s getting so frustrating and I have an art show coming up soon. I don’t know why it just started in the last year when I have been working with clay for 5 years. 🙁

  17. Hi Ginger
    Thank you so much for listing the do’s and don’t’ when using polymer clay. I’m very interested in starting to sculpt detailed models/dolls and wanted to ask what is probably a silly question. When working on a sculpture/ doll that could take weeks to eventually finish, what would be the best way to store the sculpture/doll when not working on it? I’m worried that if I start a model and maybe go back to it in a couple of days time, that I won’t be able to work some more on that particular area.
    Thank you for listening to my rambling!

    1. Not a silly question at all. The best thing is to set it aside and make sure that it’s covered to protect it from dust. Sometimes you can get cracking if you let something sit for too long and then try to work on it again, but that is more like months than days. If you are working on something very large you may prefer to bake in stages. Some sculptors bake at the end of every sculpting session, adding more clay the next time. You can bake as many times as you want. It’s a way of preventing damage to previous areas.

  18. Doreen Neilley

    Thank you, Ginger.

    So, when you say not to use nail polish as a glaze, I assume that would apply to using it like a paint, to colour the surface of areas of the clay? RATS! I have some gorgeous colours of polish, and I never do my nails lol! I bought it all for playing with my polymer clays. Oh well, I want to try resin pouring paintings, and I may be able to incorporate the polishes into that.

    1. Oh no! Well, nail polish isn’t always a bad thing. Some polishes work with some clays. So if you have them already, go ahead and give it a try. I don’t generally recommend using them because it’s pretty hit-or-miss. But since you have nothing to lose, give it a try.

  19. Thanks Ginger, With your MeasurePro thermometer, can you leave the probe and cord on the oven the whole time youre baking or are you testing at certain times only ? Im looking at a similar one here in Australia

  20. Pingback: KatersAcres 15 Common Polymer Clay Mistakes You Need to Know - KatersAcres

  21. Great Article! Thank you. You approach poly clay problems as a scientist! I will keep this article, and reread it. Thanks for helping me avoid some of the same mistakes.

  22. Rebecca Doremus

    Hello Ginger and thank you for this terrific article on surface treatments and sealers. I was wondering if you have ever tried using Kiwi Neutral Shoe Polish, Magic Shine for shoes, wax or Renaissance Wax for the same purpose? I have used all of these on small pieces in a very thin layer and then buffed. Each is a little different than the other and I primarily use it on Sculpey III and Premo (all versions). I have had great results and a little goes a very long way.

  23. Hi Ginger! Thank you for all your great tips! I have a question regarding sealers/glazes. I found a cute video on polymer clay earrings and have made some encased in brass. The light coloured clay ones have faded or discoloured after applying a sealer. I used Mod Podge Dimensional Magic after my items cooled. The video had suggested using this but the light coloured clay has totally faded!
    Any suggestions?

    1. I’ve never had polymer clay fade after applying any varnish or “sealer”. I’m not sure what’s going on. Are you sure the Dimensional Magic isn’t cloudy and it appears that the clay has faded? It’s quite common for dimensional glazes to turn cloudy. You can read more about the various types of clearcoats and why dimensional glazes aren’t the best thing to put on clay in my article on Understanding Glazes, Sealers and Varnishes.

  24. Ginger, my daughter made a bunch of covered pen barrels for Christmas gifts and we followed directions in her sculpey book for baking. The pen barrels all melted and the sculpey split all over. It was so heartbreaking and she had put so many hours in to these. What went wrong???

    1. Oh no! That’s awful! The problem was that the wrong kind of pen was used. Some pens will expand in the oven, causing the clay to split and fall off. The best beginner pens to use are Bic Stic pens. Don’t use generic ones from the dollar store…many are the wrong kind of plastic. I’m surprised that the Sculpey book didn’t tell you what kind of pens to buy. If they didn’t, I’d contact them and tell them your experience. Please have another go at it. It’s hard to start over, but setbacks are a lesson for kids to learn, too. She’ll be even more experienced the second time. 🙂

  25. Thank you for all the information. I have a question about the digital thermometer for checking the oven temperature. Because they have a probe that is designed to be inserted into food, where do you place the probe? Just lay it on the oven rack? Thanks in advance for the answer.

    1. Yes, just lay it on the rack in the oven. It will fluctuate more than a dial thermometer will because it’s sensing minute changes in the temperature as the oven cycles. But in my experience it will generally show the correct temperature.

  26. Great tips, especially your tips on baking. I recently completed a piece that was very thick…probably 1.5 inches in the body. I baked for about 23 minutes at 275 (or so my oven claimed anyway). To my dismay, after taking it out, I noticed several hairline cracks. It took days to create the sculpture, so I tried using liquid polymer clay cured with a heat gun (I use genesis heat set paints). This covered the cracks, but as I added and cured paint, more cracks just endlessly sprung up. It was a real disappointment. So I’m guessing 23 minutes for 1.5 inches is not nearly enough time, and I need to check the temp on my oven. I was pretty confident my build up and preparation of the clay was ok (the clay is the Sculpey Firm, and I buy 3 boxes at a time from Amazon, which is usually dry and crumbly until I add clay softener throughout). Hopefully the baking process is my issue :-). Thanks!

    1. There’s more than one thing going on here. Underbaking is an issue, certainly. But also, baking anything thicker than 1/4″ at a time runs a huge risk of cracks being formed. Always bake a center first, then add more clay on top of that, making each layer no thicker than about 1/4″ thick with each baking. You can also use a compressed foil core instead of baked clay. The point here is that thick pieces cure on the outside while the inside is still being cured. This causes cracks on the outside.

  27. Hi Ginger, I am a middle school art teacher and I stumbled across your site looking for answers on crumbling clay. I was wondering if you could give me advice on keeping Sculptey clay from crumbling on foil armatures before they are baked. I have to bake 130 sculptures with foil armatures over several days, so during that time ( even though they are in Ziplock bags) some of the clay begins to crumbling off the foil ( I have added masking tape to the foil-mummy style and that helps some). I tell the students to work the clay first, then to apply thin ( no more than 1/4 inch layer), and then to smooth over seams and cracks, but still I seem to spend hours fixing cracks of sculptures I can’t get to for a day or two. Thanks

    1. Polymer clay won’t dry in the air, so it shouldn’t be crumbling and falling off the armature on its own. Is someone disturbing them? Polymer clay will sometimes crack when re-worked after a long period of time, and sometimes cracks can appear, but not usually in a few days. This makes me think you might be using an air dry clay instead of polymer clay? Which brand are you using?

  28. can anyone tell me if i can use a metal bowl as mold for cooking polymer clay in the oven or should i use a glass bowl?

  29. Hi Ginger,

    Thank you for sharing all of this helpful information!

    I really want to try using liquid clay on some of my charms. Is it okay to use sculpey liquid clay on fimo clay? I always worry about baking too long and leaking chemicals into my oven.

    Thanks for your help!

  30. Benjamin Stevens

    I have watched several you tubes from Giovy Hobby. Does anyone know the type of polymer clay the use. When it comes to carving details like he shows my clays just don’t hold up. I use mostly Sculpey

  31. Jennie Rasmussen

    Hi.
    I hope you can help me with my problem. I do not make jewelry from polymer clay, instead I make things for dollhouse 1:12. I have made a lot of beet root canes (3 to 6 millimeters thick), that I firstly baked for 30 minutes. When finished they were extremely bendy yet brittle, so I baked them for another 20 minutes. Normally I would be able to cut very fine slices without a problem, but no matter how I cut and no matter how sharp the knife, it just crumbles into tiny pieces. My theory is that I have baked them so long, they became too dry. Is there any way I can save them? For example soak them in oil?
    Thanks.

    1. Generally, polymer clay only becomes tougher and less brittle the longer you bake it. It does not “dry out”. Your 30 minute bake was likely not hot enough and the second bake of only 20 minutes was not long enough to allow complete fusion of the clay mass, especially if your oven is not hot enough. Get an oven thermometer and adjust your oven to the correct temperature (most dials are wildly inaccurate). Then bake your can for an hour. That should solve the problem.

      However, slicing baked clay is always tricky. Not all brands are “elastic” after baking and will be susceptible to breakage. Make sure you’re not using Sculpey III for this as the clay is quite brittle after baking. I’d use a brand like Fimo Professional or Cernit to be flexible enough to allow easy slicing after baking. Also, you’ll likely want to heat the cane before slicing.

  32. This was such a fun read! I have one little detail to add to point 6, referring to storage and buying a limited amount of polymer clay. Sometimes it is best to buy the extra clay while still fresh and store it in air tight containers to preserve them, because I do notice some stores still have the same batch from my last purchase after months. In other words, the clay they are selling becomes hard to the touch, but it’s still on sale either way. And when buying online, you can’t ‘feel’ the clay you are buying, sometimes ending with an old hardened block instead of the fresh and soft ones.

    1. Yes, stores often keep their stock for a long time. Online sources typically have a much greater turnover and the clay is usually very, very fresh. The problem with stocking up is that some clay brands get harder over time, regardless of how they’re stored.

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