Mason stains in the G2926B base glaze at cone 6

This glaze, G2926B, is our main glossy base recipe. Stains are a much better choice for coloring it than raw metal oxides. Other than the great colors they produce here, there are a number of things worth noticing. Stains are potent colorants, the percentages needed are normally much less than metal oxides. Staining a transparent glaze produces a transparent color, it is more intense where the glaze layer is thicker, this is often desirable in highlighting contours and designs. If you add an opacifier, like Zircopax, the color will be less intense, producing a pastel shade the more you add. The chrome-tin maroon 6006 does not develop well in this base (alternatives are G2916F or G1214M). The 6020 manganese alumina pink is also not developing here (it is a body stain). Caution is required with inclusion stains (like #6021), the micro-bubbling here is not likely because it is overfired (it is rated to cone 8), adding 1-2% Zircopax normally fixes this issue.

Related Pictures

Souvenir mugs that demonstrate incredible workmanship, glaze recipes, use of decals

These porcelain mugs are sold at many tourist shops on the Alaskan cruize circuit. Made in China of course. But their quality is astounding. And they teach multiple lessons to potters - great skill in the use of decals (even inside), meeting different glazes at the rims, evenness of application, layering, the use of wax resist, etc. They likely have a glossy and matte base glaze and add stains (to get the black, blue, red, white, green). Notice they have an iron red (lower right) that is stable enough not to run and host an even more fluid melt second layer. They also have a stoney yet functional matte white (bottom left). You can make dipping glaze versions of all of these:
Black glossy: G3914A and G2926BL
Black matte: G2934BL
Iron Red: G3948A
White stoney matte: G2934Y2
Glossy colors: Add stains to G2926B
Matte colors: Add stains to G2934

When using stains, customize the percentage, host glaze and firing schedule

These are G2926B clear glazes with stains added and fired at cone 6. The one on the left has 11% Mason 6021 encapsulated red. It is pebbling the surface (even with 2% zircon), it may be at the upper end of its firing range. Possible solutions are faster firing up and down to give the stain less chance to decompose. Or firing at cone 5 instead. Or a drop-and-hold firing schedule. Or a lower percentage, that could impart a bit of variation where it is thicker and thinner (like the purple one). A different host glaze, perhaps one with less boron. The purple one has 10% Mason 6304, it is not affecting the glossy glaze surface. But the percentage needs to be higher to prevent the wash-out of color where it is applied thinner.

G2926B cone 6 transparent liner glaze: Proven, reliable, durable

A hand made pottery mug with clear liner glaze

While colorful and layered glazes on the outsides of pieces get lots of praise and glory transparent or white glazes providing the functional surface on the insides of pieces often get little attention from potters. Really, what good is an attractive piece if the food surface is crazing, blistering, leaching or cutlery marking? Or if it converts the piece into a time bomb? This cone 6 liner glaze, G2926B, is an example of how I found a glaze, recognized its potential and then adjusted the recipe to resist crazing on our clay bodies, fire durable and leach resistant act as a base to host colorants, opacifiers and variegators. I get the best fired results using the C6DHSC firing schedule and very good performance as a dipping glaze when the slurry is thixotropic. One of the reasons this recipe is so widely used is that it is well-documented having a code number that Google indexes. Drinking from a mug having a quality and fitted functional surface and a nice crisp line dividing the outside and inside glazes instills pride in me as the maker. What is the outside glaze? It is the G2934Y matte base recipe plus 8% Mason 6027 stain. The clay is MNP which I make myself.

Mason stains in the G2934 matte base glaze at cone 6

Stains can work surprisingly well in matte base glazes like G2934. But they perform differently in a matte host glaze. The glass is less transparent and so varying thicknesses do not produce as much variation in tint. Notice how low many of the stain percentages are here, yet most of the colors are still bright. A good reason to minimize stain concentration is to avoid leaching. We tested 6600, 6350, 6300, 6021 and 6404 overnight in lemon juice, they passed without any visible changes. It is known that MgO mattes, like this one, are less prone to acid attack that CaO mattes. A down-side to the MgO-matte-mechanism is that chrome-tin stains do not work (e.g. 6006), high CaO content is needed in the host glaze to develop the color. The inclusion stains 6021 and 6027 work very well in this base. As do the 6450 yellow and 6364 blue. And the 6600 produces an incredible gunmetal black. The 6385 is an error, it should be purple (that being said, do not use it, it is ugly in this base). The degree-of-matteness can be tuned by blending in some G2926B glossy base.

Links

Materials	Stains Mason
Materials	Mason 6600 Black Stain A cobalt-containing stain useful in bodies, engobes and glazes at a wide range of temperatures.
Materials	Stain 6666
Materials	Stain 6006
Materials	Stain 6500
Materials	Stain 6134
Materials	Stain 6201
Materials	Frit VO 6134
Materials	Stain 6100
Materials	Stain 6300
Materials	Stain 6364
Materials	Stain 6385
Materials	Stain 6404
Materials	Stain 6450
Materials	Mason 6027 Stain
Materials	Mason 6021 Red Stain An encapsulated red stain, it has proven better than any other red we have ever tried for glazes. And it works in bodies.
Articles	Concentrate on One Good Glaze It is better to understand and have control of one good base glaze than be at the mercy of dozens of imported recipes that do not work. There is a lot more to being a good glaze than fired appearance.
Glossary	Cone 6 Also called "middle temperature" by potters, cone 6 (~2200F/1200C) refers to the temperature at which most hobby and pottery stonewares and porcelains are fired.
Glossary	Ceramic Stain Ceramic stains are manufactured powders. They are used as an alternative to employing metal oxide powders and have many advantages.
Glossary	Medium Temperature Glaze These are stoneware glazes that fire in the range of 1200C (2200F). They often contain boron to assist with melting.
Glossary	Base Glaze Understand your a glaze and learn how to adjust and improve it. Build others from that. We have bases for low, medium and high fire.
Glossary	Colorant In ceramics and pottery, colorants are added to glazes as metal oxides, metal-oxide-containing raw materials or as manufactured stains.
Recipes	G2926B - Cone 6 Whiteware/Porcelain transparent glaze A base transparent glaze recipe created by Tony Hansen for Plainsman Clays, it fires high gloss and ultra clear with low melt mobility.

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