More Glaze Testing

On a beautiful rainy Saturday I find myself in a fantastic mood, accomplishing chores around the house and letting things flow as they want.

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Today I’m making test tiles and planning more experiments based on the cone 6 accident where the white glaze over iron oxide ended up clear and giving a slight sheen and some tooth to the clay. I have a lot of tiles already but most of the early tests are not to my liking. I’m honing in on my color palate and once I get that down I can better create what it is that is “previsualized” in my head.

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(On a side note I’ve been looking for some wooden stands for festival displays and found these for $5 at Family Dollar of all places. its meant as an over the sink shelf. Cant go wrong with that price)

Previsualization is the key to a lot of arts. Photography comes to mind and its where I learned to see the finished outcome before I made my adjustments and pressed the shutter. Ansel Adams was a master of that. What he had in his head he was able to bring out in the darkroom.

Here is how I make my test tiles.  I roll out the clay suppporting the rolling pin between two yardsticks to get a consistent thickness. I then use the same yardstick as a guide to cut the strips and make them 3 inches long.

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I line up the cut strips and mark them at 1 1/2″ at each end of the line. Then use the yardstick again to score a bit less than halfway through the group to give a place to bend it at around a 9o degree angle.


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Then from the kitchen or wherever I get something that can give some scoring to the top of the tiles so that I can see how the glaze performs when it pools.

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Also I am dipping a few of these into black slip as I am obsessed with the way some of the glazes turn out on a dark body. Yep I’m wearing gloves, this slip is messy!

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Finished product drying. The slip covered tiles are not pretty but they’ll get the job done.

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Next up I need to do a batch with my red clay. When they are dry I will bisque fire to cone 04. I will keep some of these without glaze and fire to cone 6 so that I can test a few glazes over the iron oxide and black slip. Cone 6 is vitrified so I expect that the tiles wont pick up much of the glaze at all but I might come into something interesting. If its interesting and repeatable I want to continue testing it 🙂

This is the “boring” part of ceramics. The tedious testing and logging but with the occasional surprise that makes you go “Hmmmm… what if I ….”. And also the test tiles that you hate may end up growing on you after a while. Or if not they might spark an idea for another avenue of experimentation.

Some of my favorite test tiles & a new book

One of my favorite books I’m currently reading is a sort of conversation between master potters Bernard Leach and Shoji Hamada. Some of the anecdotes had me smiling or outright chuckling. IMG_3692

My Rootbeer glaze test. Needs further testing to see what it will actually do on a cone6 fired body and if it will even still contain the bubbles. IMG_3700

Raven slip on white clay body looks very dynamic and interesting.IMG_3701

Key Lime glaze on raven black clay body.IMG_3702

Azurite on raven black clay body.IMG_3703

Ginger Mist and Caramel Corn glaze on speckled clay body.IMG_3704

Azurite on red clay body.IMG_3705

Test Tile Kiln Opening

Oh I love love love the surprises you get from opening the kiln after a long wait to come back down to temperature. I am certainly appreciative of the work that goes into commercial glazes but I already see that there are properties of each one that I want to enhance or reduce. That kind of thinking is going to get me into some rabbit holes I can already tell.



The black slip over the different clay bodies worked perfectly! It really gives that deep dark almost burnt in reduction look.


Here are a few examples of how it will look when using the glazes over the slip on the right hand side. I didnt have enough space to do a test with the double glazes over black raven body / raven slip but I’ll do that next time maybe if I feel like there is any potential for something radically different.


For now though I think I have enough data to pare down my choices and drill down deeper into fewer variables. I’d like to eventually get to one or two clay bodies that do exactly what I want them to do and maybe dabble in some porcelain as it has that certain allure for potters. Can you say: Cone 10 – wood fired? Wow!

The best of the home processed clay turned out with a little surprise at cone 6 – black specs, I guess iron or some other mineral. With maybe a very small percentage of plastic clay I think it would be very workable. I may try something small even without the mix to see how it performs.


As always. Kiln wash is a must unless you just love buying new shelves.