10 July 2010

Pitfire

Last Wednesday we held a pitfire with a group a ceramist. We gather every Monday evening (except school-holidays) to clay together. Twice a year we do a firing together either a RAKU or a pitfire.

The weather was great, which is good cause we have to dry our pieces before going into the pit. We make the pieces beforehand, so they can be bisque fired, on the day itself we treat them with iron-sulfate or cobalt-sulfate which give orange or blue colors. I wanted to try and see if I could keep the head of the sheep more neutral, so I tried how covering them with slip would work on one bowl (first picture). I choose for iron-sulfate this year.








In the fourth picture you might recognize some pieces I made on the etsy craft party, the items in the brownish clay (paper clay) for the pitfire. I bisque fired them in a bowl I used previously for a cobalt-pitfire, you can still see the blue tones on the bowl.

Once all pieces were treated and were drying in the sun, we built the pit. A layer of 5cm of wood shaving goes on the bottom. We had 2 layers of stones all around when we started filling the pit with our pieces. Than we added coffee, horse manure, seaweed, salt (all dried throughly) for extra effect. Filled all the holes in between the pieces with small wood, on that go larger chunks. We added an extra row of stones, to make the fire higher. We finish with newspaper, lampoil and some small wood to get the fire going.









Once the firing was going we turned to our other baking: we all bring some food and have a wonderful lunch while the fire burns. We chatted a lot and we discussed last seasons achievals and our projects for next year. We will hold our very first exhibition in the garden of one of our group in September 2011 and we decided on the common factor.

Every so often we checked the fire once it had burned away for 1/2 to 2/3 we covered the pit with an iron lid (sits ready in the second picture) being careful to leave airing holes.









After approximate 5 hours all wood had burned and we could open the pit and let it cool. The heat had been well on, we had a nice breeze and lots of small dry wood so the blue did come out real well and the oranges of the iron-sulfate too. You can see if you look at the bowl with all my beads and little items in the previous and above picture that where the coffee pad has been it turned all black. Good to know for a next time. The other look all orange, but when cleaning shades and specks (made by seaweed and salt) will appear. I'm still cleaning the beads, one by one.....the excess iron which has not fired onto the pieces has to come off. This needs to be done, cause they need to be oiled to fix and deepen the color. If the pieces are not clean, the excess iron will just dissolve in the beeswax-oil and make it all orange again, loosing the nice shades. More on that in a separate blog.

1 comment:

  1. Oh wow, it looks like it was heaps of fun!

    ReplyDelete