Skip to Content

Can You Bake Polymer Clay on Glass? (And is It Toxic?)

Can You Bake Polymer Clay on Glass? (And is It Toxic?)

Perhaps you have an old bottle of Jack Daniels that you don’t want to throw away. Or maybe you found a beautiful glass vase at a garage sale and want to give it a new life. Whatever the case, you’re wondering if you can add some unique flair to these glass items by baking polymer clay on them.

You already have some experience with polymer clay and know you can use it to create all sorts of fun and exciting objects. But still, you aren’t sure whether or not it’s safe to bake polymer clay on glass. After all, we’ve all heard stories here and there that glass and oven don’t mix. So, can you bake polymer clay on glass?

Well, I guess that’s the question running through your mind. And in this article, we will be unveiling every iota of detail that you need to know about baking polymer clay on glass. So, without doing much ado, let’s get started!

Can You Put Polymer Clay on Glass?

Yes, you can put polymer clay on glass. Glass has a high enough heat tolerance to withstand the oven temperatures necessary to bake polymer clay. However, there’s a catch – the piece of polymer clay won’t remain stuck to the glass after baked. So, if you want the polymer clay to stay on the glass surface, keep some adhesive within your reach.

If you enjoy creating something beautiful and extraordinary from what seems ordinary, then you know that polymer clay is one indispensable tool for your crafty projects.

This material allows you to invent all sorts of exciting things, and stick them onto your select surfaces, often leaving anyone who sees your work in awe. Even so, it makes sense to first find out if the material you want to bake your polymer clay on fits the bill.

And yes, for the glass surfaces, it surely does! You see, glass has adequate heat tolerance and can withstand the baking temperature for polymer clay. However, there is one tiny problem that you need to know.

When you bake polymer clay on glass and take it out of the oven, do not be surprised when the polymer clay pops right off. That’s because the two materials have different coefficients of thermal expansion. So, they expand and contract at different rates when heated or cooled. As a result, the polymer clay will not remain adhered to the glass after being baked.

So, if you want the polymer clay to stick onto the glass even after being put in the oven, you will need to use an appropriate adhesive.

And as usual, always avoid exposing glass to sudden and drastic changes in temperature to prevent it from breaking. That includes heating it up too quickly or cooling it down too abruptly. It’s best to place the glass into the oven before heating and then turn on the oven to the required temperature.

Is Polymer Clay Toxic After Baking?

No, polymer clay is not toxic after baking. Polymer clay is of PVC (polyvinyl chloride) and will break down to hydrogen chloride gas when heated. Fortunately, for the most part, this gas is non-toxic and dissipates quickly. But again, always take safety precautions seriously if you love using polymer clay for your projects.

Polymer clay won’t become toxic once it comes out of that oven. However, stick to the standard ground safety rules when dealing with this material, whether baking or after baking.

They include but are not limited to;

  • Avoid cooking in the same oven when baking polymer clay.
  • Work in a well-ventilated area
  • Avoid putting food on polymer clay surfaces.
  • Don’t place the unbaked clay near the brim of the glass or any other part that goes into the mouth when using it.
  • If possible, don’t mix your baking items with other utensils.

Can You Bake Polymer Clay With Aluminum Foil Inside?

Yes, you can bake polymer clay with aluminum foil inside. In fact, some people are already doing it. However, unlike glass, aluminum foil may leave some shiny spots on the clay, which may somewhat affect the final look of your work. But if that isn’t a significant issue for you, then go ahead and give it a try.

One thing we must acknowledge about aluminum foil is that it’s one invention that has significantly impacted the kitchen. Whether you’re throwing a BBQ party and want to keep your food warm or trying to bake a cake or some other type of pastry, this material always comes in handy.

The same goes for when you want to bake polymer clay. Because aluminum foil is an excellent conductor of heat, it will help to evenly distribute the heat throughout the clay, allowing it to bake perfectly.

Even so, one thing to expect is tiny shiny spots on the clay where the aluminum foil was in contact with it. Of course, that creates a great significance in the underneath side of the clay. But if that’s okay with you, that ceases to be a concern and makes aluminum foil a viable option for baking your polymer clay.

How Do You Keep Polymer Clay From Sticking to Glass?

If you are wondering how to keep polymer clay from sticking to glass, then you’re simply getting worried for nothing. The thing is, polymer clay won’t stick to glass in the first place. After baking, polymer clay ceases to be sticky to glass, so you don’t have to worry about it getting stuck.

Polymer clay sticks on anything – including you – when unbaked. So, it makes sense to worry about how you can keep it from sticking to a glassy surface. But the good news is, there’s really no need to worry about that because, as we said, it won’t stick to glass even when baked.

Now, the only time you might worry about polymer clay sticking to glass is when you’re using it for a project that needs two-part epoxy. But even then, it’s not the clay sticking to the glass but the epoxy. So, all you need to do is use a non-stick release agent on the glass before you start working with the epoxy.


Can You Bake Polymer Clay in a Glass Jar?

You indeed can bake polymer clay in a glass jar. In fact, if you intend to use the polymer clay you are baking on a glass jar, the surefire way to have the final baked product conform to the shape of the glass jar is by baking it on the said container.

One property of polymer clay is that it takes the shape of anything before you bake it. So, if you intend to stick it to your glass jar after baking, make sure to bake it first on the glass jar itself. Doing so ensures that your final product will indeed have the same shape as your glass jar.

Alternatively, you can use an identical jar, say a set member, to bake your polymer clay. That’s especially helpful if you have several jars and don’t want to risk passing each of them through the oven.

What Can You Bake Polymer Clay on?

You can bake polymer clay on anything that can withstand high temperatures, including glass, ceramic, metal, and even stone. However, you must remember that specific projects only call for some surfaces and not just any.

As aforementioned, polymer clay sticks to just about anything. So, any surface here should work just fine. Some of the commonly used ones for this assignment include;

  • Glass
  • Wood
  • Metal
  • Bead making rack
  • Baking sheets

So, provided that you have any of these in your list of supplies, you’re good to go. But again, some projects call for the use of some surfaces and not others. For instance, you’ll need to use bead-making racks and not any other surface for projects involving beads.

Can You Bake Polymer Clay With Metal in It?

Sure, you can bake polymer clay with metal in it. Most metals have a softening point above the recommended baking temperature range of 210 to 300 degrees Fahrenheit. But again, like glass, the baked clay may not stick to the metal, especially if the material has a smooth surface.

You see, baked polymer clay doesn’t work well with non-porous surfaces. That’s because, much like glue, the clay needs to adhere or grip on something for it to work. So, if you’re working with an utterly non-porous metal surface, you will need to bring in a reliable adhesive to re-stick the clay to the metal after baking.

Thankfully, the market offers a wide variety of adhesives that should work just fine for your project. Some of the standard adhesives include;

  • Super glue
  • PVA glues
  • E6000
  • Urethane glues
  • GS Hypo cement

Does Polymer Clay Harden as it Cools?

Yes, polymer clay hardens as it cools. But for that to happen, you must first bake the clay at the ideal temperature range and for the correct amount of time. After the clay has fully baked, it cools gradually as it hardens. Baking it and leaving it to cool is the only way to harden clay polymer.

You see, it’s natural to think that leaving polymer clay in the open will mark it dry. But that’s not the case. You can harden this clay by heating it within the ideal temperature range and for the recommended time.

As for the temperature, it can range anywhere between 210 and 300 degrees Fahrenheit. It depends on your specific clay, so read the product label carefully.

Now on time, it’s all about the thickness of the clay. The thicker your sculptures, the longer it needs for them to bake fully. However, the general rule is that every 1/4-inch thickness needs 15 minutes.

So, ensure that you get the ideal time by dividing the maximum thickness of your piece (in inches) by 1/4 and multiplying it by 15 to get the time in minutes. For instance, if the thickest part of your piece is 1/2 inch, you’ll need to bake it for 30 minutes (15 minutes x 2).

Final Verdict

You can bake polymer clay on glass as it works just fine. However, ensure that you follow precautions when doing so. For instance, the heat increment needs to be gradual and not sudden. Any sudden temperature change can cause significant stress to the glass and make it shatter. Also, use an oven thermometer to monitor the temperature inside the oven to avoid overcooking your clay.