You may be perfectly happy with clay right out of the package; Fimo in particular comes in some beautiful colors. However, sometimes you can't find just the right color in the clay brand you want to use. Here are some tips for mixing colors:

To make intermediate (secondary) colors, add together two primaries that tend toward the color you want. For example, to make orange, combine a warm red (one with no tinge of purple) and a warm yellow (one that's a little orange, rather than a little greenish). Adding a cool (greenish) yellow to a greenish blue will make a bright green; but adding a warm yellow to a cool (slightly purple) blue will make a dull green. Adding red and blue will make purple: a deep bright purple if you choose a slightly purplish red and blue, a dull brownish-purple if you choose an orangey red and a greenish blue.

To make a color less bright without changing its value, add translucent. You can also add white, but adding too much white will lighten the color as well as making it less bright, an effect you may not want. Add up to a third of translucent clay for this effect.

To make a semi-transparent wash of color, add colored clay to translucent. Start with a pea-sized ball of colored clay to a golfball-sized ball of translucent clay.

To brighten a color and give it more "punch", add a small amount of fluorescent clay in a similar color. For example, to make pink brighter, try adding a little bit of fluorescent orange.

Remember to start with the main color and mix in small amounts, gradually, to avoid going too far - for example, to make a translucent red, start with a lot of translucent and mix in small amounts of your red until you get the effect you want.

When two colors of clay are thoroughly mixed, the distinction between them disappears. However, if you stop the mixing partway, you'll get a streaked effect similar to marble. (Make sure not to stop mixing in time to preserve the marbled grain you want; continued handling of the clay will mix it further.)

Different color combinations can give you the effect of various semi-precious stones: for example, marbling several shades of green with white produces a clay that looks like malachite. Marbling earth tones and translucent gives the effect of agate. Pearl white with small amounts of dark gray and translucent makes a good marble.

You can vary the marble effect by mixing the clay in different ways. Roll the partially-mixed clay out into a thin snake, or pull it, to obtain narrow streaks. Running it through a pasta machine one or more times produces a different sort of streaking. Repeatedly twisting and folding the partially-mixed clay strands can make an effect like natural amber. Once you learn how to marble the clay, try different techniques at different points in the mixing for subtly different effects.

You can roll out the marbled clay and use it to make (or cover) flat items such as boxes and frames, or roll small bits of the clay to use as beads. Large marbled beads are especially effective. You can also use marbled clay as part of a cane design.

How can I make a color gradient?

Many clay artists use continuous shades of a single color, from light to dark; the work of City Zen Cane in particular makes much use of this technique. One method of obtaining such a gradient is simply to mix seven or eight shades by combining the base color with different amounts of white, then flatten each shade into a sheet and stack the sheets in order from dark to light.

An easier method for mixing a gradient has been described by Judith Skinner: you make a triangle of white and a triangle of the color you want to blend, put the long sides together to make a rectangle, and run this sheet repeatedly through the pasta machine, folding it in half each time, until the colors are blended together. You can use this same technique to blend two colors, or even use several tall triangles (instead of just two) to create a multi-color blend.

Conditioning is the process that makes polymer clay ready to work with. Most conditioning is done simply by working the clay with your hands until it reaches a good working consistency. The warmth of your hands combined with the physical process of stretching and compressing the clay changes its texture, making it softer and more pliable.

Why should I condition clay?

Conditioning clay softens it, making it easy to work with, mold, and roll into canes. It also makes the clay stickier and less brittle, letting you roll thin sheets and reduce canes without causing the clay to crack and break.

(There are a few techniques that don't require clay to be conditioned beforehand. These are mostly techniques where the brittleness of unconditioned clay is desired.)

Some clay brands are so soft out of the package that you'll be tempted not to bother with conditioning, but you will find that taking the time will improve both the workability of the clay and the strength of your fired pieces.

How do I condition my clay?

The simplest way to condition polymer clay is to work it with your hands for several minutes. Take a chunk of clay of a size you feel comfortable working with, half an ounce to an ounce or so, and begin squidging it between your fingers. As the clay warms and softens, start rolling it between your palms into a snake shape. Then move your hands against each other in a circular motion to compress the snake back into a ball. Repeat this process several times.

How long do I need to condition the clay?

As a rule of thumb, you should condition clay for the amount of time it takes to thoroughly blend two colors. (Take a bit of clay of each of two colors and condition them together, timing the process; when you can't see the separate colors any more in the blended lump of clay, the clay is conditioned.) This time can vary depending on the type of clay you're using, your style of conditioning, the amount of clay, and the temperature, but usually it takes something between three and ten minutes.

The clay's texture changes during the conditioning process. As you get more experienced, you'll be able to see and feel this change to tell when your clay is completely conditioned.

How can I speed up the conditioning process?

Conditioning large amounts of clay can take enough time and effort to be annoying, particularly if you have arthritis in the hands, or are using a stiff clay. There are a number of ways to make conditioning faster and less hard on the hands:

Pre-warming the clay

You can start the conditioning process by putting the clay in a warm place for fifteen or twenty minutes; for example, you can stick the packages you'll be working with in your clothes (some people sit on the clay packages), or use a hot-water bottle. Warning: Excessive heat or ultraviolet light will cause the clay to start curing, making it unusable except as scrap. Don't put the clay in the sun. If you're using a heat source such as a lamp or heating pad, make sure the clay does not get much warmer than your body temperature.

Chopping the clay

Many clayworkers use a food processor to chop up the clay. The small chopped bits are easier to work with than large chunks, and the friction of the blade warms the clay. After chopping the clay, you dump out the chopped bits, press them together with your fingers, and continue the conditioning as described above.

There are a number of things you can add to polymer clay to make it softer:

Eberhard-Faber (makers of Fimo) make an item called "Mix-Quick", which is a solid block of extra plasticizer; you can add Mix-Quick to your clay up to a third of the total.

Sculpey Diluent is a liquid that does essentially the same thing, softening clay when you add a few drops.

If you're using a stiff clay, you can add as much as a third of Sculpey transparent to soften the clay without changing the color.

You can also mix a few drops of mineral oil or a dab of petroleum jelly into polymer clay. (Add only a small amount; it's easy to overestimate how much you need.)

Using a pasta machine

Another method of conditioning is to press soft clay into a sheet and put it through a pasta machine, on the widest setting. Fold the sheet in half and put it through, fold-first, and repeat this process ten or fifteen times. (This method can only be used with soft brands of clay, or clay that's already partly conditioned; putting stiff clay through a pasta machine will only shred it.)

Whichever method you use, make sure your clay is well-conditioned before you use it, since under-conditioned clay can cause you problems in workability and reduce the strength of your finished items.

Is there such a thing as too much conditioning?

There's no way for clay to be "too well-conditioned", but some clays (particularly Sculpey) get softer and softer the longer they're worked and the warmer they get. If your clay is getting too soft for the technique you want to use, you can let it rest overnight, or chill it for an hour or so, to firm it up. (Chilling or resting will not make the clay lose its conditioning, so you don't need to re-condition after this.)

If you've added too much Diluent or mineral oil and have over-softened the clay, try flattening it into a sheet and leaving it between sheets of blank newsprint overnight. The newsprint will absorb some of the plasticizer, making the clay firmer. (Don't use printed newsprint; the clay will pick up the ink.)

Why won't my clay soften?

If clay has gotten partially cured, it will be crumbly and refuse to condition no matter what you do to it. This can happen if the clay has been exposed to excessive heat or ultraviolet light - it's as though it had been partly fired, and the process can't be undone. You may be able to use it for special effects (such as embedding the hardened chunks in other clay for an interesting texture). But you can't use it the way you'd use fresh clay.

Some clay brands are just naturally stiff, however, even when fully conditioned. If you're using a stiff clay and find you don't like the texture, try using a softer clay, or mixing a soft and a stiff clay together to get an intermediate degree of softness.

Look for more details in Part 3.

Building with Polymer Clay - Part 2

Hi Jeanne...I like your 2nd installment of 'Building with Polymer Clay' I have printed the article out for future reference when it comes time to include some finer detail on my railroad. Well done on an informative article. Regards.....Dave

Dave Clarke - 09/03/2007 - 05:31

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