Why color your own clay?
FREEDOM & OPTIONS
You can purchase pre-colored clay but if you want more control over color and hues I would recommend mixing your own. You can use any clay body, but white clays firing at or above Cone 6 provide vibrant color results. I prefer to mix the stains into wet clay bodies. The Mason Stain Company has a very informative web site with colors recommended for clay bodies.
Though many other stains work very well with clay bodies, you do have to buy a small sample and test them first with each clay body.
Choosing the Right Mason Stains
The Mason website has listings of all the colors available with a guide showing which ones are suitable for using in clay bodies and which ingredients to avoid in your glazes.
Why does this matter? Every clay body has ingredients in it that can react to a colorant. Sometimes that lovely pink fires green or the green turns brown because of it. If your clear glaze has the wrong ingredient in it, it will change the colors or bleed them.
You can be reasonably safe if you stick with their guidelines, but safe is not always fun. I have tried dozens of other stains with great results. The trick is to test every single batch you blend in order to see what happens to the color with and without a glaze. Then you can decide whether to keep using it or not.
I had a pink stain and a bright yellow stain ... both fired to the most lovely pale green. I would not keep these since it is so easy to forget that the color is not correct.
I would encourage you to buy an ounce or so of different colors and give them a try. Some are incredibly beautiful and are colors you cannot achieve by simply mixing two primaries.
How much Stain to use?
This is a very common question and the answer goes against intuition. The dark colors require less stain while the light colors need more. For blacks, dark blues and greens I use about 5-8% stain. For yellows, pinks, mauves I use between 15-20% stain.
I like vibrant colors and use a lot more Mason Stain by % than most do. I can always lighten them up by adding white.
It’s also much easier to store 20 lbs of concentrated colored clay then 80 pounds of pastels.
My basic Mason Stains with percentages.
#6020 Pink @ 15 – 20 %
#6450 Yellow @ 15 – 20 %
#6300 Blue @ 6 – 8 %
#6242 Bermuda Green @ 12 – 15 %
#6600 Black @ 6 – 8%
How do you measure the stain?
Say you want 10% stain, then that would be 10 grams of stain to 100 grams of wet or dry clay. I really don’t think it is crucial to use one or the other type of clay. As long as you make tests of your colors you will be able to repeat the results.
How do you mix the stain into the clay?
Even though it is a messy job, it is also a very simple job to color clay.
In order to avoid the dust problem, mix the Mason stains in a sealed plastic bag with just enough water to create a creamy solution. Then create a well in your clay and pour in the mixture. Knead the clay until you like the color result.
I use a large commercial machine to mix the stain/clay solution until the color is even throughout the clay body. You want the finished clay to be soft as cookie dough. My mixer is a Hobart A120T and is 1/2 hp. I bought it used.
Usually you mix the clay until the color is even, but you can also stop mid way to get a nice speckled effect with the color.
Some people mix small batches of colored clay as slips in kitchen type blenders. (You cannot re-use this blender to mix food).They then dry them out to the consistency needed.
You could even totally dry the colored clay, store and re-hydrate when needed. Here are some images supplied by Yvonne Cooper, one of my students of he uses this process.
**Just remember that once you use a kitchen mixer in the studio, it should never go back in the kitchen.
I always make sample discs of each color for reference. You cannot count on each batch turning out exactly the same. I also make sample discs of the colors combined with white clay and with each other.
You can expect the color to darken as you fire at higher temperatures. If you like the color when it is wet, then it is way too dark and you should add at least 50% more white clay and look again. Sometimes you can barely see the color but it is there ... mark your storage bags so you don’t confuse it with white clay
I hear comments about how expensive stains are but consider that colors last a long time. I keep colors stored in plastic bags for years with no ill effects.
Yvonne stores hers in plastic food storage containers with a fired sample on top.
**Another area of concern is safety. You do have to be careful not to inhale the dry powder while mixing, so use a proper breathing mask. . Some people choose to wear latex gloves.
I have experienced fluxing with some blue stain colors when they are used in a very concentrated form so you do have to prevent them from sticking to the kiln shelf. I sprinkle some alumina hydrate under them or put some into the wax resist when firing these.
For more options and information on coloring clay, look at the WORKSHOP page of my site to find a class near you. If there isn't one, consider recommending my workshops to an Arts Center in your area.