Sunday, February 27, 2011

Making baked potatoes...

I don't remember who coined the term, but that's what Eduardo Lazo called it during his demo of ferric chloride saggar. It was a fun distraction from the Raku firings, and the processis is very simple and stepwise. Like a cooking recipe ! So let's make some baked potatoes, shall we ?

Eduardo making his baked potato

1) bisqued pots, either burnished or with terra sigillata
2) solution of copper sulfate
3) solution of ferric chloride (Radioshack sells one)
4) spray adhesive
5) aluminum foil
6) organic/inorganic matter: horsehair, rock salt, steelwool, sugar, oxide powder, seeds, cut flowers,...whatever you feel like trying

1) paint the pots with the copper sulfate solution
2) cut a piece of aluminum foil, big enough to wrap around your pot. Make a ball then gently flatten it back. The purpose is to crinkle it so it creates air pockets around the pot.
3) spray the adhesive lightly on one face of the foil and add the organic/inroganic matter of choice, in any pattern you want. The adhesive will keep most of it in place.
4) paint the pot generously with ferric chloride and wrap it with the foil, like a baked potato. That's your saggar.
5) Fire in a gas kiln, between 1000F to 1500F in 1 to 2 hours. Both the firing time and the firing temperature can affect the colorations.
6) Cool slowly in the kiln to let the colors develop, overnight being optimum.
7) Sponge the ashes off the cold pots and let them dry for two days to let the colors settle. Then wax/treat the pots. Renaissance wax is the best for high-end waxing. For a matte finish, use a light dusting with a matte acrylic spray then wax.

At the workshop, because of time constraints, Eduardo opted for a speed firing (1350F in 1h, cooling to 200F in 3h), and frankly we had some good results. But take a peek for yourself, that's what I brought back home.

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