Polymer Clay Q & A

by Holly Klaus


Polymer Clay Q & A’s


1) What are the differences between different polymer clay brands?

I have personally tried Sculpey Souffle, Sculpey Premo, Cernit, Fimo Soft, Fimo Professional, and Kato Polyclay. My thoughts and a basic comparison on each brand are below.

Cernit: Soft and easy to condition. Similar in texture to Fimo Soft. Not ideal for caning or rigid work. Best translucent options on the market. Full range of colors and finishes available.

Sculpey Souffle: A good all-purpose polymer clay. Firm but not overly so. Matte finish. Not at all sticky. Suede texture. Trendy colors, limited palette. Light and airy feel.

Sculpey Premo: A good all-purpose polymer clay. Firm but not overly so. Semi-gloss finish. Available in a wide range of colors and finishes.

Fimo Soft: Soft in texture, similar feel to Cernit. Conditions rapidly. Not ideal for caning or rigid work. Becomes sticky when over-conditioned. Full range of colors and finishes available. 

Fimo Professional: Firm in texture. Takes some time to condition. Otherwise, similar to Sculpey Premo. 

Kato Polyclay: Very firm, ideal for intricate detail and caning. Takes a long time to condition. Starts crumbly. Colors darken somewhat when cured.

Non-professional polymer clay brands, such as Sculpey Original and Sculpey III are not suitable for intricate and artisan level work.

I personally love to work with a blend of 2/3 Sculpey Souffle or Premo mixed with 1/3 Cernit clay. The Cernit softens up the Sculpey clay just a bit making it easier to work with.

2) What kind of glue should I use to adhere earring post backs to polymer clay earrings?

There are many conflicting answers on this topic online. Personally, I believe the answer lies more in the type of earring post used than in the type of glue used. I’ll go into full detail below.

I have tested E6000 glue, super glue, embedding posts directly in polymer clay, and Liquid Sculpey.

E6000 is a type of flexible glue that fully cures in 72 hours. However, it does begin to dry much sooner than that. To use this type of glue, you simply apply a thin layer of glue from the nozzle directly onto your earring post and apply it to your clay piece. This method is very easy and quick, but you’ll need to read on about surface area to ensure you create a lasting hold.

Super glue is a much firmer glue that does not flex at all. It is quite strong, but not a flexible hold. It is much runnier to apply, but solidifies within mere seconds. This method is also very fast and easy, but requires careful earring post selection as well, so read on about that.

Between these two glue options, E6000 is similar to an ultra-strong putty or extreme strength chewing gum in texture and hold, whereas Super glue is more similar to a concrete bond- firm and strong, but also shatter-able and inflexible.

The third option, embedding your earring post in polymer clay, requires that you create two identical earring tops out of clay. You then place the earring post between the two pieces, poking it through one of the pieces. Then, you gently press together and pinch edges together, making the two clay pieces one solid piece with only a stud piece sticking out. It leaves a beautiful, polished finish and looks very professional. The downside of this method is that it is very time consuming and doesn’t work very well with detail work- the sandwiching method can mush and distort intricate details. 

Finally, Liquid Sculpey is an option to hold earring posts to polymer clay. This option is extremely strong and fairly easy, making it a great option for lasting work. The downsides of this method is that it requires a double-bake, as Liquid Sculpey will not “dry out” or cure on its own, and that it can become messy. Oftentimes, makers will apply Liquid Sculpey both to the post itself and covering the entire back of the earring including the back of the post. 

Ultimately, I believe ALL of these methods can be viable options to connect your earring posts to polymer clay, with one KEY CONSIDERATION: Your earring post’s surface area! The larger your post is, the more surface area is holding it to your earring design! I find that 8mm earring posts work best, as they are large enough to provide amply hold without being too large to accommodate most designs.  

3) How long should I be baking my clay in the oven? Why?

Most polymer clay brands cure at 275 degrees Fahrenheit in a home oven. The minimum time required to cure your clay is 15 minutes per ¼” thickness of clay. However, you’ll want to let your clay cure for much longer than this if you plan on creating durable pieces such as jewelry. An hour is ideal for maximizing durability and avoiding discoloration. White , light colors, and translucent clay are most prone to discoloration if cured for too long.  

If you do burn your polymer clay, it is much more likely a temperature-related issue than a bake time issue. Polymer clay is very heat sensitive, and can burn if baked even 15 degrees higher than the recommended temperature. Conversely, you’d have to keep the clay in the oven for several hours at 275 degrees before it would even begin to discolor or burn. 

If your oven is set to 275 degrees Fahrenheit and your clay still burns, there are two potential culprits. First, your oven itself. Is it maintaining a consistent temperature over time, or is the temperature fluctuating? If your oven is not consistent, you’ll need to use a different oven. Second, the distribution. Is your tray of clay work taking up all of your oven rack? If so, the heat wave pattern inside your oven will become disrupted, causing heat to become “stuck” at the bottom of your oven, where it will heat up and cause burning. To avoid this issue, make sure you don’t overcrowd your oven.

4) How can I use translucent polymer clay in my work?

There are many different brands of polymer clay that offer translucent options. Let’s go over Sculpey Premo & Cernit brands, both of which are offered at Sun Sprinkles.

 In my opinion, Cernit offers the BEST translucent polymer clay. It is the clearest, most colorless option on the market. Meaning, the clay does not have a yellow cast once cured. It has a beautiful finish. Even better, Cernit offers a full line of colored translucent clays that can be mixed with the plain white translucent to create tinted translucent colors!

Sculpey Premo offers two types of translucent clay: Translucent and White Translucent. The difference is that their white translucent includes optical brighteners, which their regular translucent does not. However, both of these translucent clays do yellow a bit after curing. White translucent does yellow a bit less, though. Keep this in mind when deciding how to use this clay.

There are many wonderful ways to use translucent polymer clay in projects! Generally speaking, you’ll want to choose a project that is very thin, as translucent doesn’t appear see-through when too thick. It can be used to create stained glass effects, translucent designs, faux gemstones, geodes, and faux stones. It is great for layering and experimenting!

5) How do I make holes in my earring pieces to attach them together? How do I connect them together?

Many artists struggle to know whether they should drill holes in their clay earring components before or after curing them in the oven. Using a handheld drill or Dremel after curing creates much cleaner results and results in less breakage. I like to use a pen to mark where to drill if it’s a complicated piece or needs to be balanced perfectly. Any excess marks can be easily wiped off with acetone afterwards.

Connect your work using jump rings. I recommend the 10mm size, because it is easy to work with and large enough to hold bigger clay pieces together.

6) How can I clean polymer clay pieces if they get dirty?

Polymer clay can be easily cleaned by wiping it with acetone. You can clean raw or cured clay. It is often easier to clean cured pieces so that you don’t accidentally ruin your design. If you applied a surface application to your clay, do not use acetone as it will wipe your design off.

7) Can I decorate polymer clay? What can and can’t be used with polymer clay? 

There are a lot of mediums that work well with polymer clay and can enrich your making experience. Here are just a few:

-Pepper: Can be mixed into raw clay to give it a speckled or granite effect.

-Mica Powder: Can be applied onto raw clay for a very shiny finish, or mixed into raw clay for a semi-shiny finish.

-Acrylic Paint: Most acrylic paints work well on polymer clay. If you are testing a new brand, be sure to do a test swatch to make sure the paint adheres well and that it doesn’t stay tacky.

-Copic Markers/ Prismacolor pens: These pens can add detail to polymer clay as well

-Sealers: You do have to be very careful about choosing a sealant for polymer clay, as most will not dry fully and will leave the surface of your clay sticky and tacky, ruining all of your hard work. Sculpey makes a satin and gloss glaze that fully dry, so that lint and dust do not stick to your finish piece. 

-Resin: Be sure to use proper safety equipment when around or using resin. Resin can be used to add depth and shine to polymer clay after it is cured.

8) How do I store polymer clay?

Remember, polymer clay is a plastic-based clay. It can react with and liquify other plastics if they are not compatible. Regular ziplock bags work well to hold polymer clay. Plastic numbers 1, 2, 4 and 5 should all work for storage. If you are unsure, you can place a small amount of polymer clay on a surface for a few minutes and see whether it becomes sticky or not.

9) How can I firm up a piece of polymer clay that is too sticky?

To firm up polymer clay, you’ll need to leach it.  To leach clay, roll it out using an acrylic roller or a pasta/clay machine.Then, stick your clay slab between a few pieces of paper and apply some pressure. Ideally, you should leave your clay like this overnight, but you can press firmly several times in a pinch.

Another way to firm up polymer clay is to cool it down. It is completely safe for your clay to be refrigerated or frozen, and it will not ruin your clay. I often put my finished polymer clay canes in the freezer the night before I plan to put them up to avoid distortion.

10) How can I soften clay that is too hard and crumbly?

To soften up polymer clay that is too hard to work with, add a few drops of oil to the clay and mix thoroughly. Mineral oil and baby oil work best, but oils such as coconut oil and even vegetable oil can work in a pinch. If your clay is too crumbly to mix, toss the crumbles of the clay with a small amount of oil in a resealable plastic bag and leave it overnight. It should be easier to work with the next day.

It should be noted that there is no way to soften polymer clay that has already cured. If your clay has been exposed to excess heat or sunlight for an extended period of time, it is likely unsalvageable.

11) Why are there bubbles and lumps in my clay after I baked it?

We’ve all had the frustrating experience of making a gorgeous clay piece, only for it to come out of the oven lumpy and bumpy. What happened?!

Air pockets in your clay lay flat while your clay is raw, and heat from curing your clay in the oven causes the trapped air to expand. There is no way to revert this process, so prevention is key 

To prevent bubbling, condition your polymer clay carefully. Always use outward motions when rolling a piece of clay, similar to how you’d apply a sticker to avoid bubbles underneath. When you fold a piece of polymer clay, stick the folded side into the pasta/clay machine first, so that you aren’t trapping any air in the fold.

When conditioning a lump of clay in your hands, use stretching motions to help break bubbles.

12) How can I avoid a flat spot on a 3-D clay design?

Lay your object in a pile of baking soda rather than lay it flat on a pan and cure as usual. You may need to clean up any excess residue from the baking soda with some acetone or sanding afterwards.

13) Can I mix different polymer clay brands?

You can mix any professional polymer clay brand without issue, as long as you accommodate any differences in baking temperature. For example, if one brand cures at 275 Fahrenheit and the other at 265 Fahrenheit, cure your mixed clay at 270 Fahrenheit.

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