Atmosphere
What is gas firing and why do I do it?
For those of you who are new to handmade pottery (making, using) you may not know that there are different ways pots are fired (heated until the glaze turns to glass). Most pots are made in an electric kiln as they are easy to use (they plug into the wall and most come with programmable firing settings) and most commercial glazes are formulated for this type of firing.
Some pots are fired in a hole dug in the ground - called pit firing (check out an amazing UK based artist that uses this technique http://janewhiteceramics.com/pit-firing/ ) or in a metal barrel or by a similar technique called Western Raku firing where you pick up a molten pot with tongs and place it in a barrel with horsehair and newspaper. These techniques are fun and beautiful but the pots are typically not functional for food and therefore not thing (I like to make functional work).
So that brings us to gas firing… which is simply a kiln that is fueled by natural gas or propane. It requires someone to monitor the firing from start to finish (typically a 12 hour gig). At my studio this kiln is called ‘big blue’ and I love to fire her. She is a pain to load (heavy shelves, awkward spaces) but I feel more connected to the process when I have placed every pot and cone pack and am monitoring the temperature every 30 minutes. Beyond the participatory part, this kiln provides a reduction atmosphere which means that when the inside of the kiln is deprived of oxygen it seeks to pull any hidden oxygen from the glaze and the clay body to compensate. This gives the pots a beautiful glaze result with iron flecks (the clay I use has a bit of iron in it), creates blushing if a pot with a copper glaze is next one that is not copper, creates tea dusting effects (flecks of gold) in the tenmoku glazes, and just generally has more variation of effect of a glaze. Don’t get me wrong, sometimes the result is NOT what I was looking for (pots meet the hammer in that case).
Mostly gas firing allows me to experiment with the glaze surface in a way I just can’t in an electric kiln. If you are looking at pots in my shop, all the pots glazed in Storm, Snow, Mulberry, Midnight, Yellow Salt, RiverRock, and BlueGreen are from the gas kiln.
I also love wood firing but that is for another blog post.