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Minnesota Clay Co. USA Technical Info - Using Commercial Stains

Mason and Drakenfeld Colors
Click here for Stain Color Sheet

Minnesota Clay USA gets this question almost daily: "Can you tell me how to use Mason or Drakenfeld Stains? Well, there is a lot of confusion about these colors and we think a little background will help.

First, if you've ever used any of the common oxides (iron, cobalt, copper, etc.), either as the pigment part of a recipe, or as an oxide wash, you've probably noticed that these colors have a fair amount of color variation. Speckling, shade and hue changes are part of the charm of oxides and carbonates. Unfortunately, most of these materials also bring toxic solubility problems to the equation-especially in the raw state.

Mason and Drakenfeld colors use oxides in their compositions, but these colors are calcined and ground to a fine particle size. I visited a color plant in 1987 (neither Mason or Drakenfeld) and their process was as follows: first the oxides would be blended following a recipe, the materials would be loaded into saggars and fired to a prescribed temperature (@ 1800 F. is my guess). The cooled mixture would then be placed into large grinding mills to obtain a particle size range.

The firing of these colors makes the oxides in the mixture less soluble than they are in the raw state. That does not mean that they are absolutely safe to handle however; you should handle these materials with equal care as oxides. Be sure to wear protective equipment including but not absolutely limited to gloves and masks.

The result is a fine-particled color that is extremely stable in most formulations fired up to cone 8. Some people use Ceramic Stains like oxide washes, but my experience is that this is often results in a rough, refectory surface when used under glazes. Ceramic colors function best as the pigment portion of: glazes at 3-12% levels, underglazes at 3-20% levels and colored clays at 3-20% levels.

The following colors are ones that have unique qualities and perform well in particular recipes.

Manganese-Alumina colors like Mason 6020 Pink and 6319 Lavender are extremely stable (yet somewhat refractory) at temperatures above cone 5. These colors work especially well in slip and clay bases. Chrome-Tin pinks (Mason 6001-6006, Drakenfeld 4144) generally don't do as well above cone 5, except in glaze recipes that are low in boric oxide and zinc.

Chrome-Tin Pinks (marked Cr Sn Mason 6001-6009, 6023, Drakenfeld 4144 and 41188) seem to be the most problematic for users of ceramic stains. Generally these colors benefit from a formulation that is: high in Calcia, has some sources of Soda and Potash, has low levels of Boric Oxide, Magnesia and contains no Zinc. Also Chrome-Tin pinks will fade when exposed to a reduction atmosphere.

Use 1-10% Mason or Drakenfeld color in a glaze formulation, 3-20% in a clay or slip formulation. Some potters use these materials mixed simply with water, however these products are not designed to work in this way and usually this sort of technique will result in a rough covering glaze surface, color that will crawl, or decoration that will crack off.

While ceramic stains are more stable, predictable and generally less hazardous than metallic oxides and carbonates, personal protection measures must be taken to ensure safe use. Be sure to read and understand the product's Material Safety Data Sheet before using it.

Drakenfeld 51358: This Chrome-Iron Black often times performs as well of better in a recipe than more expensive black stains that contain cobalt.

Drakenfeld 41509 (Mason 6390) Turquoise and 41545 Yellow: Both colors are extremely stable at any temperature. If anything, these colors can be a little stark when used on their own in a glaze, clay or underglaze recipe. But they can be great for fine-tuning a color towards a particular hue.

Zircopax and Superpax: Neither of which is a ceramic stain, but can be essential as a source of opacity (whiteness) in a glaze, under-glaze or slip formulation.


Mason Color Works Ceramic Stain FAQ

Q. Why do I not get good pinks or crimsons at Cone 06/2/5/10, etc.?
A. Mason’s chrome-tin pink series, #6000 to #6006, are stable from Cone 06 (normal "low" temperature) to Cone 12 (normal "high" temperature). This type of pigment requires the correct glaze chemistry in all temperature ranges, in order to maximize the "color value". High calcium content is most important, and zinc & magnesia must be low to zero. Boron should not be too high. A major complication is that these rules do not necessarily apply when "fast firing" techniques are used. Second, these pigments need an oxidizing atmosphere throughout the firing cycle.

Q. When I use black stains to make gray shades they turn green/brown/blue/pink, etc. Why are they not simply gray?
A. Do not use black stains to make gray shades by using small amounts in the glaze. Blacks are made of combinations of cobalt, iron, nickel, chromium, manganese, etc., and if low percentages are used the resulting color is often that of the predominant oxide in any particular black pigment. Again, care should be taken to use the correct glaze chemistry to avoid combinations that create color problems. It is better to use the gray pigments that we offer.

Q. Why does my green glaze turn brown or has brown edges? A. This is usually due to the presence of zinc. Remove any zinc from the formula, because it turns chromium brown in most situations. Additional calcium may help.

Q. Why does my glaze appear "milky"?
A. Too much boron in the frit or glaze formula, under-firing, or the presence of opacifier in amounts greater than 2%.

Q. Why is my purple/lilac/violet glaze turning blue?
A. Some of these pigments are made of chrome-tin pink and cobalt. (See Q. #1). Sufficient calcium is needed to support the "red" side of the mixture.

Q. How do I make a nice red-brown using your regular brown pigments?
A. The base glaze should contain from 3-5% zinc. This supports the red side of the stain.

Q. My blue under-glaze runs, creating a "fuzzy" appearance. How can I prevent this?
A. Cobalt silicate is very soluble in the glaze, so it is better to use cobalt aluminate, or a combination of both. Too high a temperature can also cause this effect.

Q. Can I mix pigments to make my own color palette?
A. Yes, in most instances. However, some stains are incompatible with others, so if you do not achieve the result you want you should phone the Mason laboratory for further information.

Q. Do your pigments contain lead compounds?
A. No. Lead compounds are not used in Mason pigments.

Q. What are "encapsulated" pigments? A. Encapsulation is a special, patented, manufacturing process designed to incorporate certain metallic oxides into the crystals of zirconium oxide. They are also referred to as "inclusion" pigments. They are safe to use, and are now widely used in ceramic manufacture around the world. Obviously, as with all finely dispersed powders, care should be taken to keep operations as dust-free as possible.

Q. Can you help me with technical problems, glaze formulas, etc?
A. Yes, most certainly. Our technical support staff will offer advice on all ceramic manufacturing problems, and will be happy to supply body, glaze and engobe formulas on request. Obviously, no guarantees or warranties are expressed with such information since all ceramic operations differ in crucial ways, but we will try to help you with your difficult problems.

Q. Where can I find Material Saftey Data Sheets for the products you offer?
A. We now offer all of our MSDSs online for download. You can find them here.

Didn't find an answer here? Contact Technical Support Here.

Click here for Mason Color Works Ceramic Stain FAQ