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. |