How To Keep Bubbles Out Of Your Polymer Clay

Avoiding Bubbles Polymer ClayVideo #371: Tricks of the trade to help make your polymer clay projects look more professional.

Topics Covered In This Video:

  • Trapping air in your polymer clay as you work with it can cause disappointing bubbles to rise to the surface of your finished pieces.
  • Avoid using squishy clay as a way to avoid trapping air in your polymer clay.
  • Use a thicker setting on your pasta machine.
  • Don’t trap air in the folds of the clay, make sure it has a way to escape.
  • Gently pull sheets in both lengthwise and width wise to help release trapped air from clay.
  • Bake flat polymer pieces in a tile sandwich (smooth tile on bottom – paper layer – clay in middle – another paper layer – smooth tile on top).
  • Bake pieces upside down to let the air rise to the back of the piece rather than the front.
  • In a future video I will show you how to fix or minimize the look of bubbles should they still appear after taking these precautions.

Question of the Day:

Do you have problems trapping bubbles in your polymer clay pieces? And what have you done about them in the past?

By the way, if you have a polymer clay question or challenge you’d like me to address in an upcoming video vlog, do post it in the comments below. I’d love to help you find quicker and easier ways to bring up the professionalism in your polymer clay art.

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Looking forward to hearing from you!

Cindy Lietz SignaturePolymer Clay Tutor
  1. Shye K, 11 April, 2013

    sigh.. i just had this problem yesterday! probably didn’t put folded side down in the pasta machine…

  2. Marcela S, 11 April, 2013

    Thank you Cindy!!

  3. Carrie C, 11 April, 2013

    Preaching to the choir! Tried to cover a project the other day and >thought< I got all the bubbles out between the layers :(

  4. Ella M, 11 April, 2013

    Great tut again!!!

  5. Nettonya R, 11 April, 2013

    Funny, that you couldn’t find any bubbles at first! I noticed that when you put the bunched pc in the machine, you put it in with an opening pointing upward! Lots of years of “automatic” practice!

  6. Cindy Lietz, 11 April, 2013

    Nettonya, yeah I saw that too. Had to force myself to do it wrong and still let the good habit slip through! lol

  7. Sue F, 12 April, 2013

    Excellent information as always, Cindy!

    One suggestion I have for dealing with air bubbles is to use a sharp blade, holding it at an angle where it’s almost flat rather than straight up and down, and slice into the air bubble at one of its sides before pressing the air out and re-sealing the sliced part. That will be almost invisible, and much less noticeable than the mark you’d get if you cut into the bubble with a near-vertical blade or if you just poked a hole into it with a skewer or other sharp point. That can be important when the air bubble happens when you decorative sheet is ready or almost ready for use!

    Also, deal with air bubbles when you notice them. If you keep conditioning air-bubbled clay the bubbles might appear to go away, but sometimes the trapped air simply becomes distributed so finely that it no longer makes noticeable bubbles when the clay is uncured. These can still cause dimpling or uneven surfaces when the clay is cured as the air expands, and they can also create visible imperfections in translucent clay.

    Finally, I don’t quite agree with the recommendation to condition clay at a thicker setting, at least for Kato Polyclay.

    Kato is more easily and more quickly conditioned at a medium to medium-thick setting than at a thick setting, and because it’s firmer and less sticky than many other brands this doesn’t seem to increase the likelihood of air bubbles being trapped. On my latest pasta machine I do most of my conditioning at the third and fourth thickest settings, which are 2.1mm (roughly 6 playing cards thick) and 1.5mm (roughly 4 playing cards thick) respectively.

    Additionally, if you have any Kato of the previous formulation that tended to crumble, it’s almost impossible to condition at a thick setting! You’ll just get handfuls of crumbs and small pieces which you’ll have to try to squish together to feed through the machine, which is extremely frustrating. You’re also fairly likely to have some air trapped between those collected squished bits, so using a thick setting is counterproductive with that type of clay. For that Kato formulation, I start by working my way down to a medium thin setting before I do any folding, and I do much of the conditioning at medium thin before backing off to my normal medium setting once it’s behaving fairly nicely.

  8. Jocelyn C, 12 April, 2013

    Thank you Sue!

    Love the stretching technique Cindy. Find that works really well. Weird that Kato responds so differently, but I agree, it does. Wonder why.

    Also, I weight stuff, lots of tiles after I turn it right side down. Think it smooshes the air out.

  9. Lyn Tremblay, 12 April, 2013

    Hi Cindy: new to your blog and am enjoying all of your great tips. In regard to fingertips I find texturizing my pieces does prevent them from showing up as much so I do that whenever possible. I use sheets of paper canvas a lot because they give a subtle texture and are easy to put through the pasta machine with the clay. I also use pieces of them exclusively when finger-pressing pieces (I.e. if producing petals or thin discs) – cut pieces of canvas about 1″x2″ and fold in half so that you end up with a piece that you can press the clay with between your thumb and index finger. This way both back and front of the piece gets textured at the same time as well.

  10. Jan G, 17 April, 2013

    I use wallpaper samples to texture clay. They come in all sorts of nice textures – like linen or leather or carving. The “dryness”of the paper stops it sticking to the clay, or you can use mica powders or cornflour as a release. Also, you get them free from wallpaper shops.

  11. Sharon A, 12 April, 2013

    You are such a doll, Cindy! Love your lessons!

  12. Dixie Ann, 12 April, 2013

    Good information here, I do have periodic problems with bubbles from time to time, I think everyone does. I like Lyn’s suggestion of using paper canvas too. My question is how much is too much weight to put on a flat piece of clay while baking it? I normally sandwich my flat pieces between 2 tiles like Cindy shows in her video. Jocelyn says she adds a lot of weight. So if I am baking a flat pendant and I have turned it upside down, is one tile enough or should I use more and if so how many? I did notice when baking my last piece which had a slightly domed top, it flattened it out more just using the one tile. I thought it looked better with the slightly domed top but it did come out bubble free.

  13. Cindy Lietz, 16 April, 2013

    I generally don’t weight mine with anything more than a tile but if you are having problems, then definitely try it. If I am pretty sure my clay went in bubble free, then sometimes I don’t worry about even placing the top tile on (like in the case of a domed piece like you were mentioning) but I do try to at least turn it upside down. I can still end up missing some though (like in the Butterfly Barrette I showed in the tutorial the other day.) I was able to pretty much fix that though with the re-heat method. So all is good… Phew!

  14. Peggy R, 13 April, 2013

    I just found you, Cindy and it is so refreshing to see that you are “real” on your videos! Great tips and will be back to see more. Thank you!

  15. Cindy Lietz, 16 April, 2013

    So nice to have you here Peggy! I am so glad you found us. Welcome to our little clay family. make sure to ‘take a swim’ in the sea of information around here! I think you are going to love what you learn!

    Thanks for leaving such a kind comment! I really appreciate what you said. Hope to see more of you around here!

  16. Basti A, 28 July, 2014

    Hi Cindy! (: I tried dping them but bubbles keep on showing. Now, thing is that Im currently using Du-kit for my projects and I accept orders. I’ve only just begun and I dont have a budget for an oven. Instead of using an oven, I use an oven toaster. I have my thermometer to check the heat. I alsohppen to have a pasta machine and usually knead using it. Bubbles just keep showing up even if I try those… please help…. ):

  17. Cindy Lietz, 29 July, 2014

    Hi Basti, I am not familiar with that clay, but if it is quite sticky you may find it traps air easily. Use the search box to find info on leaching the clay to make it firmer. And when you roll it through your machine make sure to put the fold side in first so that you aren’t trapping air in. Plus when the sheet comes out of the rollers, give it a tug to stretch the clay and release the air. For anymore info, try the search box. Good luck!

  18. Carole C, 17 April, 2013

    Hi Cindy:
    My issues with bubbles always shows up when I’m trying to cover clay with a decorated sheet, I’ve tried adding the sheet to raw clay and I’ve tried adding it to baked clay to try to solve the problem. I suppose that part of the issue is that I’m not seeing the bubbles before baking.

  19. Jocelyn C, 23 April, 2013

    One tip that might prove useful is to apply a thin layer of polymer clay glue on both pieces, then slowly but surely ease the fabric on in one direction, carefully smoothing as you go. Using a bright concentrated light source and a magnifier can help spot those bubbles the second they crop up. Working in one direction at a time helps guides the bubbles out to a seam, where they escape. Always try to work outward, never inward, since inward seams to trap more air. Hope that helps. Also would use the search facility for links, there are a ton of suggestions here on this site that will prove useful. All best.

  20. Erza G, 17 April, 2017

    hello Cindy, ,i’m pretty new learning and making some polymer clay jewelry ,, these day, i make character charm with translucent clay, it’s not flat but round shape like a bead,, i’m using translucent fimo and premo, after bake its seems there are cracks inside my charm, i’m pretty sure already roll it many times and bake it on top ceramic tile with some paper layers also cover it with some layers,, but it always crack inside.. how to avoid that bubble trap on my translucent charm beads?

  21. Cindy Lietz, 20 April, 2017

    Hi Erza, those little cracks in your translucent are what we call plaquing. It is caused when a little bit of air or moisture gets trapped in the clay and causes a little split. Some brands do this more than others, but they all pretty much do it. When working with translucent, try to keep your hands dry and don’t overwork it. Be careful not to trap air. Pop any bubbles and give flat sheets a tug to help release the air. Just know that it is normal to have some plaquing and embrace it if you can. :)

  22. Emma D, 02 June, 2017

    Hi Cindy,
    I make fantasy art dolls and I’ve been sculpting with polymer clay for years on and off. I condition the clay by hand but air bubbles have always been a bit of a problem in flesh coloured clay. I recently got the Atlas pasta machine you recommended with hopes of finally eliminating the problem. However I seem to get more bubbles than ever now, I put the fold through first like everyone advises but this doesn’t seem to help. I think also what happens is when the edges have that torn look they seem to trap air in here when they’re folded. It’s very frustrating I wondered if you can help? Also the one thing that seems to be missing off anyone’s tutorial is once you have all these flat sheets of clay how do you get them back into a thick block again without trapping any air? many thanks, Emma

    Ps love the you tube vids

  23. Cindy Lietz, 02 June, 2017

    Thank you Emma! The issue is not the machine or the torn edges. Super soft clay can trap bubbles. You may need to leach some of the plasticizers out to make it firmer. There are some videos on how to do that. Also try pulling the sheets to release the air. That will help. As far as getting back to a thick block, you can fold it back and forth like an accordion to shape it into a block. If the clay is a little firmer you won’t have the same issues with the bubbles. Hope that helps!

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