Saturday, April 28, 2012
Fun With Ceramics & Glazing
Wednesday evening, I had my third ceramics class. I thought we would be making more pieces to be fired for the first time and I had a few ideas about what I wanted to make (a bowl or a wrapped vase). However, our instructor wanted us to glaze the pieces we finished in our previous classes so she could fire them for the second time over the weekend. She wanted us to see the colors and gloss of our finished work before we continued on and made more pieces. Based on what she said, it seems that although you chose a color(s) of glaze, the color of your finished product is really unknown until you open the kiln after the second firing. The glazes can vary in color based on the amount of glaze applied, where the piece is placed in the kiln, how many pieces are being fired, and how hot the kiln is (or isn't).
Glazing is the process of applying a layer or coating of a substance to a ceramic piece and then fusing it to the piece through firing in a hot kiln. If I remember correctly, I think the kiln is run at a temperature of 1000 degrees Celcius. Quite hot. The glaze is used to color, decorate, strengthen and/or waterproof a ceramic piece. We used liquid glazes which contain various powdered minerals and metal oxides. Since our pieces were not that large, we applied the glaze with brushes but glaze can also be applied by dipping, pouring or spraying. We had to apply two coats of the glaze but it soaked very quickly into the porous clay and was dry in no time.
The glazes were in plastic bottles, much like finger paints. However, the color of the glaze in the bottle was not an indication of the color the piece would be after the second firing. For example, I chose to glaze my pieces using a variety of blue glazes - I think I used teal, aquamarine and sapphire. However, as you will see in one of the photos below, the glazes were grey upon application. I even got a little daring and used two different colors on one piece - aquamarine for the first coat and then sapphire for the second coat. Our instructor had a few samples of pieces that she had made using two different colors of glaze and they looked so pretty so I thought I would give it a go.
I had four pieces to glaze - a 5x7 picture frame, a 3x4 plate, a 5x7 plate and then a much larger plate (about 9x11).
I made the larger plate last week and it looked really great after the first firing.I love the detail of the stamps I used for texture and design.
The photo below shows the glaze applied to about 1/2 of my larger plate. I applied the aquamarine glaze first and then the sapphire glaze.
This photo shows the larger plate completely glazed and ready for the kiln.
I think I used the aquamarine glaze on the picture frame and the sapphire glaze on the smallest plate. I did not get to start to glaze the medium sized plate but it might be good to see how these colors turn out before I glaze anymore pieces.
As much as I enjoy sharing my misery, I promise that I will stop posting these "cut and pastes" of our weather forecasts. However, I thought the forecast this morning was interesting because April is said to be the hottest month here and the extended outlook shows such a noticeable and definite cool down beginning May 1st. I can only hope it is accurate!