Mason stains in the G2934 matte base glaze at cone 6

Stains can work surprisingly well in matte base glazes like the DIY G2934 recipe. The glass is less transparent and so varying thicknesses do not produce as much variation in tint as glossy bases do. Notice how low many of the stain percentages are here, yet most of the colors are bright. We tested 6600, 6350, 6300, 6021 and 6404 overnight in lemon juice, they all passed leach-free. The 6385 is an error, it should be purple (that being said, do not use it, it is ugly in this base). And chrome-tin pink and maroon stains do not develop the color (e.g. 6006). But our G1214Z1 CaO-matte comes to the rescue, it both works better with some stains and has a more crystal matte surface. The degree-of-matteness of both can be tuned by cooling speed and blending in some G2926B glossy base. And it’s easy to turn any of these into brushing or dipping glazes.

Related Pictures

5% titanium dioxide in G2934Y matte, G1214Z1 matte, G2926B glossy

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The body is Plainsman M390. The firing schedule is Plainsman PLC6DS.

Mason stains in the G2926B base glaze at cone 6

19 glazed porcelain tiles showcasing Mason stain colors

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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; the percentages needed are normally much less than for metal oxides. Staining a transparent glaze produces a transparent color, it is more intense where the laydown is thicker - this is often desirable in highlighting contours and designs. For pastel shades, add an opacifier (e.g. 5-10% Zircopax, more stain might be needed to maintain the color intensity). 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). Bubbling, as is happening here, is common - this can be mitigated by adding 1-2% Zircopax.

G2934 cone 6 DIY MgO matte glaze: Reliable, durable, adjustable, stainable

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These pieces were made from Plainsman Polar Ice and fired to cone 6 using variations on the PLC6DS and C6DHSC schedules. The dipping glaze is G2934Y, a recipe variant of G2934 having a finer micro-surface texture (it has the same chemistry but the MgO is sourced from a frit and talc instead of dolomite). These mugs display how well the recipe works with stains and the varying degrees of matteness we can achieve by varying the cooling rate and the percentage of glossy G2926B base blended in. As an MgO matte, this glaze can have a surface pleasant to the touch. It fires durable, can be quite matte without cutlery marking and it has very good slurry and application properties (as a dipping glaze). It has a very low thermal expansion (won’t craze). It works really well with stains (except purples). It melts even better than the glossy!

Here is my setup to make brushing glazes and underglazes by-the-jar

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Let's make a low SG version of G2934BL, totally DIY. Weigh out a 340g batch of dipping glaze powder. Include 5g Veegum (to gel the slurry to enable more than normal water) and 5g CMC gum (to slow drying and impart brushing properties). Measure 440g of water initially (adjusting later if needed). Shake-mix all the powder in a plastic bag. Pour it into the water, which is blender mixing on low speed, and finish with 20 seconds on high speed. This just fills a 500ml jar. In subsequent batches, I adjust the Veegum for more or less gel, the CMC for slower or faster drying and the water amount for thicker or thinner painted layers. Later I also assess whether the CMC gum is being degraded by microbial attack - often evident if the slurry thins and loses its gel. Dipping glaze recipes can and do respond differently to the gums. Those having little clay content work well (e.g. reactive and crystalline glazes). If bentonite is present it is often best to leave it out. Recipes having high percentages of ball clay or kaolin might work best with less Veegum. Keeping good notes (with pictures) is essential to reach the objective here: Good brushing properties. We always use code-numbering (in our group account at Insight-live.com) and write those on the jars and test pieces. This is so worthwhile doing that I make quality custom labels for each jar!

Links

Materials	Stains Mason
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.
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	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	Medium Temperature These are stoneware glazes that fire in the range of 1200C (2200F). They often contain boron to assist with melting.
Recipes	G1214Z1 - Cone 6 Silky CaO matte base glaze This glaze was born as a demonstration of how to use chemistry to convert a glossy cone 6 glaze into a matte.
Recipes	G2934 - Matte Glaze Base for Cone 6 A base MgO matte glaze recipe fires to a hard utilitarian surface and has very good working properties. Blend in the glossy if it is too matte.

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