A test kiln: Enabler to testing glazes

And to evolving your own glaze recipes

The evolution of the quality and aesthetics of your work, and even your ability to cut costs, are stunted when you depend too much on others (e.g. for firing, for premixed glazes). This mug is a good example of tests I need to do. This is G3933, made by adding iron oxide, rutile and tin oxide to a 75:25 blend of our base matte and glossy glazes (G2926B and G2934).
-It is crawling at some of the sharp angles of the incised decoration, would a little CMC gum fix this?
-Would an 80:20 blend of the two glazes give a little more matteness?
-Our red-burning body gives better color at cone 5, would this glaze be richer and more matte on it in the C5DHSC slow cool schedule?
-I want to test increases in the rutile (for variegation), iron (for better color) and granular manganese (for more speckle).
-Would a Ravenscrag Slip base glaze be a better host for the rutile, iron and tin?
Having a small test kiln puts all of these changes on my radar. An account at insight-live.com to document everything well brings it all together.

Related Pictures

A test kiln with firing controller: A necessity.

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Every potter should have one of these. Every clay body manufacturer should have one. This one has a Bartlett Genesis electronic controller, you will never go back after having one. Start with a kiln like this and then graduate to having a large, second kiln (or more of these if you are doing lab or development work). We have done 950 firings on this one in the past few of years, it is still like new. Ongoing testing is the key to the constant development of your products and their quality.

A modern electric test kiln, a marvel of utility

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This is a ConeArt 119D, 0.57 cu ft, 11"x9" cone 10 test kiln. While there is 120v model, don't take a chance, go with 220v (actually ours is 208v). Ours fires 1000 times on a set of elements, mostly in the cone 4-7 range. The old BX controller is shown here, it is $300 cheaper, but don’t even think about getting that! Do not use your electric like a pop up toaster, make it a technological enabler of custom firing schedules, get the Genesis GX. Having good control of firing is a key to success and this is superior for that. These kilns are economical to fire. Big enough for 5 mugs, but I typically fire a dozen clay and glaze test specimens. We make our own super-thin shelves. The controller holds about 20 schedules, even controllable remotely (it is Wi-Fi connected). We can fire cone 04 up and down in three hours! Of course, since this type of kiln can enable so much more testing you also need a code numbering system and a place to record and search all the results: An account at insight-live.com.

The recipe mixing area in the Plainsman Clays lab

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This is my lab work area of mineral, frit, chemical, stain and metal oxide powders for mixing test glazes and clay bodies. Not shown is my propeller mixer, perhaps the most important piece of equipment we have. And my plaster table for dewatering clay body slurries. Building up something like this, over time, is practical for any serious potter, most of these powders are inexpensive. Within minutes I can plan and enter a recipe into my Insight-live.com account, give it a code number, print it and weight it out.

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Links

Glossary

Commercial hobby brushing glazes
These are an incredible benefit to pottery beginners and pure hobbyists. But they can also be an obstacle to progress and affordability as your skills improve.

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