Wednesday, June 20, 2007

Bubbles

I'm sure anyone who has worked with clay will agree, the moment you open the kiln to get the first peek of the finished pieces is always filled with nervousness and anticipation. No matter how long you've been doing ceramics, that feeling never goes away. It is such a long process to have a piece made and there is no guarantee that your hard work will pay off. A simple bowl like the one pictured above usually takes me about two weeks.

Here's the process in a nutshell. I start with a ball of clay and throw it into a bowl on a pottery wheel. Next, I wrap it up in plastic and let it slowly dry to a leather hardness. This may take up a few days. Once it is leather hard, I bring it back on the pottery wheel so I can trim the bottom of the bowl and add signature stamp. After the piece is completely dry it is ready to be bisque fired for hours up to approximately 2012 degrees Fahrenheit. Next, I glaze the bowl using one of the designs from my sketch book. This step may take up several hours depending on the detail of the design. Once the piece is glazed, is is placed in the kiln for another firing to about 2228 degrees Fahrenheit for several more hours. The bowl is then allowed to slowly cool over the next 24 hours before the kiln is opened. It is after this second firing that I often find myself with my heart in my throat praying to the kiln god.

This time around, my heart sank to my feet. The glaze bubbled for some yet unknown reason. What happened? I don't remember doing anything different with this batch. I'll need to do research on the web (*sigh*).

3 comments:

Cynthia said...

Oh, that is a disappointment...I think I must hold my breath every time I open the glaze kiln!

Bubbles in glaze...I'd have to pull out The Ceramic Spectrum by Robin Hopper. I did, and there's a lot of reasons why glaze might bubble. Good luck in finding the answers...

Denise said...

hmmm.. perhaps the bubbles can be a "feature". :0)

Linda said...

Did you use new batch of green? Coincidentally, I use an underglaze green that's similar to the color that you're using and it's been "acting up" lately - when it's applied heavier than it "wants" to be, the texture is rather bubbly/bumpy too. I know the feeling - it's a very emotional thing, opening up the kiln.