Thursday, February 13, 2014

Raw Color

 With this nasty weather we have had, I have had to postpone my kiln firing due to the fear of raw pots freezing (overnight and while loading in 20 degree weather), and not being able to get out of the house! If you're reading this from the North, then don't laugh when I say we only got about 4 inches, but also had about 1/2 inch of ice on top of it! I don't care where you live- ice is not fun. For a town, and a state for that matter, that is not terribly well-prepared for winter weather (several counties around us are without salt), our City guys were dutifully out with plows last night and all today!
Raw clay glaze from clay dug at the farm
So I took the extra couple of days when I would be loading to make up some test slips and glazes. I am most excited to test out the clay I pulled from the holes we dug for the barn at the farm. Above is an image of the dried, crushed clay blended with 3134 Frit, in a 50/50 ratio. Bob Armfield recommended giving that a try, and I cannot wait to see the results.
Tests for the raw clay glaze
The color as a raw clay glaze is like fresh pureed pumpkin. Not the pumpkin from a can at the grocery store, but small, fall, pie pumpkin flesh- bright and lush!
Cobalt blue slip
I am always mesmerized by the change of raw materials in the kiln's atmosphere. Above is not a new recipe, but my usual blue cobalt slip. I use cobalt carbonate in my slip, which is bright pink as a raw material. When I paint it on my pots it looks like this:
Cobalt blue painted on a dish
And when it comes out of the kiln, it looks like this (usually):
What cobalt blue usually looks like after the kiln firing (painted decoration)
That transition from one color to another never ceases to excite me. In a wood-firing and salt-glazing atmosphere, I really don't have a true notion of what could happen, and whether everything will work out in any planned fashion. I try to do as minimal planning as I can so that I am not terribly disappointed after a firing!

A new slip I am trying is a white slip base with 1% manganese added to it. If you have never seen raw manganese, it is very black and makes this beautiful color when blended with white slip:
Manganese slip
I may have really high hopes, but I am anxious to see whether this color when painted on my pots like this little test vase-
-will turn out anywhere near the color on the inside of the flowers (the purple color) of this German stoneware tankard below.
Tankard with cobalt blue and manganese slip decorations. Image courtesy of Port Tobacco Archaeology Project
Hopefully with warmer weather this weekend I will be able to finish prepping the kiln and get things loaded up next week!

By the way, this is the look my chocolate lab gave me when I asked him if he wanted to come in from the snow this afternoon:
"I'm not done!"

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