Plastic Types That Are Compatible With Polymer Clay

Safe Plastics - Polymer Clay TutorVideo #765: And how to test for polymer compatibility when the plastics are not marked with any of the known recycling symbols.

When storing unbaked polymer clay, don’t just throw it into any old plastic container, because when you come back at a later date, the clay may no longer be usable.

Polymer clay is basically a plastic clay made of plasticizers, fillers, pigments, oils, binders and whatever else they put in there. When it is in it’s raw state, the plasticizers are ‘wet’ so to speak, and are available to leach out and react with whatever material they are in contact with. Some polymer clays react quite badly with some plastics, by eating into the surface and actually changing the properties of the clay.

What makes things complicated, is that there are many different types of plastics made with different materials, as well as many different formulations of polymer clay… each one reacting or not reacting in different ways.

In today’s video I talk about the different types of plastics, which ones are polymer clay safe, which ones are not, and what do when you don’t know what type of plastic you have.

In a nutshell:

The plastics with the following recycling numbers are SAFE:

#1 – PET or PETE Polyethylene Terephthalate
#2 – HDPE High Density Polyethylene
#4 – LDPE Low Density Polyethylene
#5 – PP Polypropylene

The plastics with the following recycling numbers are NOT SAFE:

#3 – PVC Poly Vinyl Chloride
#6 – PS and EPS Poly Styrene and Expanded Poly Styrene

And then there is #7 – Other… which includes a bunch of different plastics like Acrylics, Teflon, Nylon, Polycarbonate and others. This category is iffy due to the fact that some are safe, like acrylics, and others are not. So anything with a #7 symbol must be tested to be sure.

Watch the video, you’ll see what it looks like when a plastic is not polymer clay safe.

Do you have any suggestions for videos on tips, techniques or products you would like to learn more about? Let me know in the comments section below!

My goal is to help you to learn quicker and easier ways to bring up the professionalism in your polymer clay art.

Oh and don’t forget to give these videos a Thumbs Up click at YouTube if you are enjoying them. The more Likes a video gets, the higher it rises in the searches. And that means even more people will be able to join in on this polymer clay journey of a lifetime.

Also, by subscribing to our YouTube Channel directly, you will receive notifications as soon as new videos are uploaded. To subscribe, click here… How To Test Which Plastics are Safe with Polymer Clay … the Subscribe Button is right near the top of that YouTube page.

Looking forward to hearing from you!

Cindy Lietz SignaturePolymer Clay Tutor
  1. Tracey Jones, 24 January, 2017

    Hi Cindy,

    I just wanted to let you know that I recently purchased a Carpe Diem A5 Planner after watching your video on your Favourite Tools and Supplies 2016, I have to say I love it, still waiting for a few inserts to arrive but it is going to be so useful, thank you for the recommendation.

    I would also like to ask please, you have an Atlas 180 I believe and I just wondered what you thoughts were between this and the 150?

    Many thanks

  2. Cindy Lietz, 24 January, 2017

    Hi Tracy I actually have the 150. The 180 is the same only a little wider (I believe it is millimeters. SO the 150 would have rollers 150mm wide and the 180 would have 180mm wide.) The 150 are more common and is the size that most clayers have. I still love my machine, btw.

  3. Lesley Kuhn, 27 January, 2017

    Hi Cindy!
    I just got a food saver and I thought that I might used it with clay scraps and canes for storage. I can’t find anything on the website or in their literature about the plastic rating of their bags. Do you know if their bags are compatible? If not, how long should I test it for?


  4. Cindy Lietz, 30 January, 2017

    Hi Lesley, I have no idea whether those vacuum bags are polymer clay safe or not. You can usually tell if the plastic is going to be a problem or not, if it sets for just a day, but leave it for a week or more to be sure. I like to test for really long times for most chemicals, but it seems with the plastics, you’ll know pretty quickly.

  5. Tina Haskins, 04 February, 2017


    I am subscribed to your newsletter, color palettes and your YouTube channel and have been for a few years now! I love your videos and color palettes and find them very informative.

    I was telling a friend about the following product, but could not remember the name of it. You did a video once on this product that was sort of a moldable adhesive, that looked like similar in texture as the polymer clay, but it was an adhesive agent that set up after a certain period of time, and could fix things (bond things together). I remember you put some on your bead baking rack to make the slots skinnier. Can you share that video number and the product name with me?

  6. Cindy Lietz, 04 February, 2017

    Hi Tina – Glad to hear that you are enjoying the videos and color palettes. That product you are thinking of is called Sugru. Here is the link to my video post about it…

    A Sugru Hack To Keep Amaco Bead Rack Pins in Place

    Btw… the quickest way to find info on your own is to use the search box at the top of every page of this site. Even when you can’t remember the name of a product (like Sugru for example), you can still type in associated words… like “Baking Rack” in this case :)

  7. Nancy Vleurinck, 04 February, 2017

    Hi Cindy
    What about plastic examination gloves used to prevent fingerprints?
    I cant find any number on the box.
    My experience is that they tear apart at the palm.if y put them on again the next day.
    Then I cut off the fingers and can use these one more day. By then my pieces are ready to be cured and I take new gloves for the next time.

  8. Cindy Lietz, 05 February, 2017

    That I can not answer for you Nancy. Perhaps there is a recycling number on the box of gloves. That would be the only way to tell, other than doing your own testing.

  9. Marilyn Loperfido, 07 July, 2017

    Hi Cindy!
    I’m posting this as a test. I just posted a comment but I received a message that it was received as spam. So I’m just testing this to see if it goes through.

  10. Marilyn Loperfido, 07 July, 2017

    Hi Cindy!
    Maybe my first comment was too long. Here’s my question:
    I do a weekly art and craft show your around on Sundays. I have a canopy over my pieces, but at some point I will look over and see that a piece has cracked, we’re a few minutes ago it had been fine. Most of my pieces are at least a quarter of an inch thick, and I believe that I baked them at the correct temperature and time.
    I am open to your suggestions and thoughts as to why this might be happening, as well as anyone else’s input.
    Thanks so much, Marilyn

  11. Cindy Lietz, 01 August, 2017

    Hi Marilyn, great question! I have added your question to the list for a future LIVE Q&A Broadcast. Join us every Wednesday at 11AM Pacific Time on our Facebook Page to hear me answer questions just like this LIVE. If you can’t be there at that time, the replay will be available here on the blog as well. Hope to see you there!

  12. Marilyn Loperfido, 07 July, 2017

    Hi Cindy!
    I left out the part where at least at some point during the day my pieces are in direct sunlight as much as I tried to keep them covered. That part is probably important as well. Thanks again, Marilyn

  13. Ai C, 14 August, 2017

    I watched this video about Compatible Plastics With Polymer Clay
    And I have a question.
    After baked polymer clay properly, we can store every kind of containers?
    or still need to avoid such plastics for storage?

    Thank you,

  14. Cindy Lietz, 15 August, 2017

    Hi Ai, yes after the piece is baked you can pretty much store it anywhere. :)

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