The best temperature and time to bake Fimo polymer clay

Oven thermometer showing best temperature for Fimo clay.One of the most important things to know when baking Fimo is the perfect time and temperature to get the best results.

Here are my recommendations and tips for baking Fimo polymer clay projects.

The correct temperature for Fimo polymer clay

First, let’s talk about the temperature.

Different clays have different temperatures but the optimal baking temperature for Fimo polymer clay is 265 degrees Fahrenheit (120 degrees Celsius). It’s important not to exceed this temperature, and going above 170c causes your clay to burn, darken or discolour. Conversely, using too low a temperature could cause it to become brittle or crumble.

And keep an eye on the temperature, regardless of whether you use a normal oven or an air-fryer for polymer clay.

Domestic oven heat settings are wildly inaccurate. I had no idea how far off the standard oven was until I used an oven thermometer (this is my preferred choice at the moment). Now I use for the air fryer in my home studio/shed where I do most of my crafting/making but also now use use it even when cooking food!

I also preheat my oven with the clay inside it before increasing the temperature to the baking temperature. This can help to prevent sudden temperature changes that can cause the clay to warp.

And speaking of baking time…

How long to bake Fimo polymer clay

The general rule of thumb is to bake Fimo clay for 15 minutes per 1/4 inch (6mm) thickness. If your piece is 1 inch (25mm) thick, you’ll want to bake it for an hour. If I want hard-finished results, I add 5 to 10 minutes to these timings. This doesn’t hurt my humble creations but it does harden them up just a fraction more.

It’s also a good idea to keep an eye on your clay as it bakes, just in case.

Extra tips for baking Fimo polymer clay

Aside from baking for the right duration at the right temperature, you can also reduce the risk of clay cooking accidents with the following tips:

Cornstarch: Apply a thin coat of cornstarch to the surface of your clay before baking. This can help prevent cracking and warping.

Cook on a sheet: Place your creations on a non-stick baking surface – tin foil, a sheet of non-stick baking paper, or a reusable silicone baking mat such as these. This makes it easier to transfer in and out of the oven, easy to clean and allows for more consistent baking.

Cover your clay: Putting a cover over your clay while it cures in the oven can help reduce the chances of unwanted colour changes.

Position: Place the clay in the centre of the oven, away from the heating elements and sides. If it’s too close, it may get too hot or cook unevenly.

Cool down: The clay takes a while to cool down after removing from the oven. It can be surprisingly hot, so don’t touch it for at least 15 minutes after baking.

Following these simple tips and you’ll be able to bake your Fimo polymer clay creations to perfection every time! Add a comment with how you get on below.




Founder of ModelRailwayEngineer, Andy Leaning

Andy is a lifelong modeler, writer, and founder of He has been building model railways, dioramas, and miniatures for over 20 years. His passion for model making and railways began when he was a child, building his first layout at the age of seven.
Andy’s particular passion is making scenery and structures in 4mm scale, which he sells commercially. He is particularly interested in modelling the railways of South West England during the late Victorian/early Edwardian era, although he also enjoys making sci-fi and fantasy figures and dioramas. His website has won several awards, and he is a member of MERG (Model Railway Electronics Group) and the 009 Society.
When not making models, Andy lives in Surrey with his wife and teenage son. Other interests include history, science fiction, photography, and programming. Read more about Andy.

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