How to Condition Polymer Clay Until It Is Ready to Use

Clay straight from the wrapper is rarely ready to shape. To condition polymer clay you work it by slicing, squeezing, rolling and folding until it is evenly soft, stretchy and free of crumbly spots. It is the first step of every project and the one beginners are most tempted to rush.

Conditioning does more than warm the clay. Over time in storage the ingredients settle unevenly, so a block can be stiff in one area and soft in another. Working the clay redistributes them. Evenly conditioned clay bends without cracking, joins to itself cleanly, and is generally stronger after curing than clay that was shaped stiff.

What you need

• Polymer clay, about half a small block to practice with
• A tissue blade
• An acrylic roller
• A smooth ceramic tile or other clean work surface
• Clean, dry hands

A pasta machine speeds things up but is optional. If you do not own one, the list in polymer clay tools: what you need and what can wait explains when it becomes worth having.

How to condition polymer clay by hand

1. Slice the block. With the tissue blade, cut thin slices, roughly the thickness of a coin. Thin slices warm through quickly. A whole block squeezed in your fist warms only on the outside and tends to crumble.
2. Press and roll a log. Stack a few slices, squeeze them together, and roll the lump between your palms or on the tile into a log about as thick as a finger. If it cracks apart, press it back together and keep rolling. Early crumbling is normal with firm clay.
3. Fold and roll again. Fold the log in half, twist it once, and roll it back out. Repeat. Each cycle stretches and blends the clay. You will feel it change from stiff and resistant to smooth and pliable.
4. Flatten and test. Roll the clay into a sheet with the acrylic roller and fold it over on itself. Look closely at the outside of the fold. A smooth fold with no cracks means the clay is ready. Small splits or a ragged edge mean it needs more work.

How to tell when the clay is ready

Rely on what the clay does, not on how long you have been at it. Firm clay needs many more folds than soft clay, and the same block behaves differently in a cold room than in a warm one. Look for all of these together:

• A folded sheet shows no cracks along the bend.
• A thin log can be curved into a U shape without splitting on the outer side.
• The color and sheen are even, with no dry, pale or crumbly patches.
• Two pieces pressed together join without a visible seam.

Clay can also be overworked into a sticky, floppy state that will not hold a shape. If that happens, set it down and let it rest and cool before continuing.

Fixing clay that is too hard or too soft

What you notice	Likely cause	What to try
Crumbles and will not hold together	Cold, old or very firm clay	Warm thin slices in your closed hands, then press and roll small amounts at a time
Still crumbly after long kneading	Clay has dried out or partly firmed in storage	Knead in a small amount of softer clay from the same product line, or a drop of liquid polymer clay or clay softener
Sticky, limp, smears on the tile	Very soft clay or a warm room	Rest it, cool your hands, or press it between sheets of plain paper to draw out excess plasticizer
Streaks or marbling you did not want	Not blended enough	Keep folding and rolling until the color is uniform

Add softeners sparingly. Too much turns clay gummy, and it cannot be taken back out. Softening products vary, so check the label and try a small amount on a scrap first.

When using paper to firm up soft clay, press a sheet of clay between two pieces of plain copy paper and leave it under a book. An oily mark appears on the paper as plasticizer moves out. Check often, because clay left too long becomes stiff and prone to cracking.

Avoiding air bubbles while you condition

Folding traps air if you are careless about it, and trapped air shows up later as raised blisters. Two habits prevent most of it. When you fold a sheet, press from the fold outward toward the open edges so air has a way to escape. When you feed a folded sheet through a pasta machine, put the fold in first or to the side, never last.

If you spot a bubble, pierce it with a needle tool at a low angle and press the air out. The guide to troubleshooting cracks, bubbles, fingerprints and lint shows the fix in more detail.

Conditioning with a pasta machine

Roll a hand-softened slab thin enough to enter the widest setting without forcing it. Pass it through, fold it in half, and pass it through again fold first. Repeat until the sheet comes out smooth with even edges. Forcing thick or cold clay through strains the machine and shreds the sheet, so always warm the clay in your hands first.

The same folding and rolling is how two colors are blended into a new one. If you want to mix your own shades, polymer clay color mixing explains how to measure parts and record recipes.

What to do with conditioned clay

Use conditioned clay in the same session if you can. Left to sit, it stiffens again and needs a brief rework before shaping, though far less than the first time. Wrap leftovers in wax paper and store them away from heat and sunlight.

With a ball of ready clay in hand, the natural next step is practicing the basic shapes: ball, log, teardrop and sheet, which nearly every project is built from.