The cost of a kiln load
I sat down and worked out what a single firing actually costs, which I had been carefully avoiding for two years.
Electricity is the obvious line and the smallest surprise. A full cone 10 firing with a slow climb and a soak at the top runs about nineteen hours on my kiln. The meter says what it says, and it is not nothing, but it is not the number that matters.
What actually costs
Time. A load is roughly forty pots. Each one is thrown, trimmed, bisqued, glazed and loaded. Five of them will not survive to the shelf. Two more will survive and not be worth selling. So the firing cost divides across thirty-three pots, not forty, and the hours divide across the same thirty-three.
Once I wrote it down in that shape the pricing stopped feeling arbitrary. It also explained why the mugs, which are quick and forgiving, carry the studio, while the large bowls — slow, heavy, prone to exactly the foot cracks described elsewhere on this site — are closer to a hobby than a trade.
Keeping the bowls anyway
I am keeping them. Not every line in the accounts needs to earn out, as long as you know which line it is.