Sunday, March 28, 2010

Pottery: Cone packs

I've been working long hours in the pottery studio. I finally made enough pottery to fill my kiln, bisque fired, made the glazes, glazed the pottery and loaded the kiln. I'm ready to fire!

I've been experimenting with textures and carving patterns in the surface of the clay. The vase on the left became this...

....after the bisque firing (the low fire that hardens the clay for glazing).

Do you remember these?

I glazed each one in a different color.

Glazing these carved and textured pieces was a challenge. I had to make educated guesses about how the glazes would look. It will be exciting to unload the kiln and find out what the fire does to the glazes on these surfaces.

To find out how the loading of the kiln is done, check out another post I did when I was preparing for a firing.

When I fire the kiln to 2380 degrees, I rely on pyrometric cones to help me know what is happening inside the kiln.

Each cone is made to melt at a very specific temperature.

I make "cone packs" with a lump of clay to hold the cones lined up in the order that they will melt.

I place the cone packs behind holes in the kiln door and I watch them melt during the firing.

At the end of the firing they look like this. The lowest temperature cones melt into puddles. The later melting cones bend in the higher heat. When each one begins to bend I can determine the temperature of the interior of the kiln. When the last cone bends it is time to turn off the kiln.

I also have a digital pyrometer which measure the kiln temperature but these cones tell me much more than the modern technology of the pyrometer.

The challenge is to see the cones during the firing through the peep holes in the door.

The firing takes fourteen to sixteen hours. Stay tuned for a video of the kiln firing.
After cooling the kiln for two days, I'll be able to unload and see the results!

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