Potters used to working with dipping glazes that contain plenty of clay are shocked when they see what crystal glazers have to work with: Slurries that contain very little clay because the Al2O3 contributed impedes crystal growth. They end up with dipping glazes conditioned with gum and bentonite that are bummers to work with. But here is a way to mix as a gelled brushing glaze that works surprisingly well. This requires two gums. Let's mix 500ml.
Step 1: Blender-mix 340g powder into 440g water. We now have a watery slurry that settles in seconds.
Step 2: Thoroughly blender-mix 5g of CMC powder into it. We now have a slow-drying but thin slurry.
Step 3: Blender-mix in, on high speed, 6g of VeeGum. Slowly add it. We now have a gelled slurry that will stay in suspension. And paint well with a fan brush.
Full gel might not kick in until aging it overnight. Of course, if it overgels for you, then use less VeeGum the next time. Why not add the gums together or the VeeGum first? Agglomerates will form, and even the blender can't remove them.

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These seem to work well for brushing glazes whether the bristles are fine or coarse, stiff or soft. The key to their utility is the shape. Glazes are gummed and gelled. An ordinary brush, when dipped, pulls together, minimizing the total load it can hold and the breadth of stroke it can make. But these stay fanned. Each bristle has access to more glaze, and thus the brush can deliver more. The fan shape also assists in spreading it evenly over the surface; after all, that is the purpose, spreading evenly, not decorating. Gelled slurries drip much less, so a fan brush can be dipped and brushed in rapid succession. And, these brushes are much easier to clean. These were purchased at Michaels, they are good quality and inexpensive.

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Crystalline glazes are highly melt-fluid by necessity. On first seeing this, typical potters are horrified at how runny they really are. How is it possible to even use them? By making glaze catchers, custom-sized to match the base of each piece. A calcined alumina or kiln wash paste (made using CMC gum or other binder) is applied to the base of the piece so that it does not stick to the catcher. After firing the catcher is broken off and the remaining sharp glaze edges are ground off.

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This wheel-thrown bowl is large, heavy and thick-walled. There are pouring techniques to apply different colored dipping glazes inside and out, but they are cumbersome and slow. It turns out that the hobbyist way of glazing is actually better - by brushing. I make these 500ml jars of brushing glaze and tune the percentage of gums to get the right painting consistency and drying time. Applying multiple coats by brush takes only a few minutes, and no wax resist or any other tools are needed. And it is easy to meet two glazes in a straight line at the rim. On this piece, the inside glaze is G2936B and the outside is G2926B. Both are almost always used as thixotropic dipping glazes, but nothing about such recipes disqualifies them from being mixed as brushing glazes.
| Glossary |
Glaze laydown
Refers to the quality of the dried ceramic glaze layer and how this affects the fired result: e.g. density, hardness, evenness, thickness, freedom from defects, etc. |
| Glossary |
Crystalline glazes
A type of ceramic glaze made by potters. Giant multicolored crystals are grown on a super gloss low alumina high zinc glaze by controlling multiple holds and soaks during cooling in the kiln. |
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