Showing posts with label glaze. Show all posts
Showing posts with label glaze. Show all posts

Tuesday, July 10, 2012

a little bit of glaze on my nose

Back from Idyllwild, CA ! Richard Burkett, professor of Ceramics at SDSU, taught a fantastic week-long class on cone 6 glazes during the the Adult Summer program at the beatifully located Idyllwild School of Arts. Surrounded by pines trees, oaks, squirrels, and a multitude of birds, a small group of 10 people dove head first into the world of glazemaking, firing test tiles every day, mostly cone 6 oxidation in an electric kiln. Richard was very generous in his knowledge. First he shared his glaze software, Hyperglaze, with all of us. Hyperglaze is a great tool for calculating unity formulae and prepare new recipes. Then he covered the basics of making glazes, and revealed tricks and tips to solve the typical galze issues (running, crazing, shivering, pinholing, you name it) and transform a glaze into a winning color.

The class (L. to R.):
Sandra, Pierre, Elizabeth, Harriet, Merle,
Janette, Richard, Emily, Danae, Debby, Lavanya

I came to Idyllwild with three dear San Diego friends, Merle, Sandra and Danae, all with various expectations, from learning how to mix glazes to how to create a new glaze. There we rekindled with Harriet, whom Merle, Danae, and I had met last year at the Soda Firing workshop. And we made new pottery friends in the process. That's how it works at Idyllwild ! Oh, and the food on campus was excellent. Buffet style, and ice cream every day. And those almond cookies were to die for !

The workbench
In the glaze room, weighing and mixing

The girls at work
The first round of tests

Overall, I think we all met our goals. Personally, I was interested in learning the process of creating a glaze from any kind of ashes. Ashes contain all the ingredients necessary for a glaze (fluxes, alumina, silica), it is simply a matter of finding out the right melting combination. I had brought some oak ash, previously sieved. A melt test with different fluxes and frits narrowed it down to a basic recipe to explore. Tweaking the melt to give a stable glossy glaze at cone 6-7 was then quickly achieved with the help of silica and EPK. With a recipe in hand for my oak ash, I can now explore different colors with oxides and stains, as well as varying the opacity of the glaze. Exciting !

 
Ash melt tests

Oxide line blends

The class also gave me the opportunity to try out new glazes from the a few books I brought, thanks to the full access of chemicals at the ceramics studio. That's more than what I have at home, but I know now what else I should procure for my own studio. Notably a particularly useful barium frit, Ferro Frit fb284m, which alleviates the manipulation of the harmful barium carbonate.
 
A new glaze:
Pierre's strontium aqua

Oxblood glaze revisited
(cone 6 oxidation)
Hyperglaze turned out to be an invaluable tool in creating new recipes from unity formulas. Jordan, Richard's assistant for the week, tirelessly updated the sofware with our new creations, including pictures of the test tiles to match. I am already using the software to tweak some recipes that have been eluding me. Yes, you, cone 10 gas-fired glazes, I'll find a way to get you !

Tuesday, August 2, 2011

First load in the electric kiln

Very, very pleased with it ! After several rounds of glaze testing, it was time to jump the shark and apply my favorites on real pieces. I have had my electric kiln for a while now, mostly bisquing for Raku projects. Now that I think of it, August is its one year anniversary !
I started out with some old porcelain pieces I had around, made with Hagi porcelain. It's a nice porcelain to handle. The test tiles I did with it all came out better than with the cone 5/6 stoneware, for some reasons.
One of my favorite glazes so far is this red yellow speckle glaze I picked up in Book of Glazes from Emmanuel Cooper. Absolutely stunning, with reddish/brown crystals on a light yellow satin background.
Another glaze I was excited to use was a manganese crystal glaze that I adapted from a cone 10 glaze, using Digitalfire Insight software. I made two variations and they both turned out like the cone 10 glaze we use in reduction gas firing at Clay Associates studio. The tiny crystals create a deep shiny surface with a dark chocolate hue.  Definitely a keeper !
The top and inside of the floral arrangement vase consist of a layer of a clear red/black glaze followed by a layer of a rutile glaze called broken pearl to give an opalescent tint to the piece. You can see that the glaze picked up a bit of iron by the blue breaks on the inside.
The clear red/black glaze is more of a clear honey color, as seen in the bowl set. Very consistent glaze. When thick it becomes a darker brown with light gold specks. Here the bowls were sprayed with a medium application. I added a medium spray of the spearmint glaze from Roy's Mastering Cone 6 Glazes book, mostly concentrated around the rim. The effect is more muted than I envisioned. I can try dipping the rim next time.

7" high porcelain bud vase;
electric, cone 6;
red speckle yellow glaze

6" high porcelain wide rim vase;
electric, cone 6;
red speckle yellow glaze

4.5" high x 7" wide porcelain floral vase;
electric, cone 6;
clear red/black glaze, broken pearl glaze,
 manganese crystal glaze

4.5" high x 7.5" wide porcelain bowl set;
electric, cone 6;
clear red/black glaze, spearmint glaze