Raku : Pit Firing - It's a Toss Up Really
One of the motivations for moving here to La Hacienda de Media Luna/Campos de Gutierrez was the desire for a creative outlet. I personally had a drive to learn more about ceramics with everything conveniently available through Maati. We've been here in Medellin now for 44 days and we've done 2 firings. This is a walkthrough for each of the two processes which were both as unpredictable as they were exciting.
First and foremost for the Raku firing our pieces were glazed beforehand. We attempted to choose glazes with more metallic content for the effects they would have at high temperatures. One glazed we placed the work in a large barrel and then heated them quickly with a huge blow torch. Burn baby burn.
Some of our pieces were fired with the Western Oxidation-Reduction method, meaning they were quickly put into a separate canister with wood chips and suffocated of oxygen. The rest of the pieces were removed when red hot and while the instructor Lindsay Chandler manoeuvred the lid with gloves, the teacher Silvia Doncel used tongs to place the pieces on a metal plate where we then experimented with surface design while they cooled. Alcohol, wood chips, dried coffee, sugar, egg shells, feathers - we were like witches with our brews and our concoctions had varying results. I loved the "pluma" or feather effect on some of my pieces but I'm not a huge fan of the chartreuse green glaze.
I had the privilege of working alongside ceramicist Addison Woolsey for this firing. The pots were bisque fired the day before, however, before we bisqued I was excited to experiment with Terra Sigilatta after falling in love with Jane White's Ceramic Review. I figured she's on a farm, I'm on a farm - let's give it a go. A bit naive I know, but I went ahead and made two batches of "terra sig"; one with 15ml of sodium silicate and the other with 30ml added to a coffee jar full of slip. The 30ml seemed the right consistency. This was as good a guess as any other as I have neither seen nor used "terra sig" before.
With my version of terra sig applied, I chose to coil copper wire around them. Addison experimented in his own way too by making his own slips from locally sourced clay bodies mixed with fresh ash. Then in a brick-lined pit we put sawdust, wood shavings, dried leaves, along with some chemical compounds for colouring and salt. We packed the pieces in the pit and carefully built a pyramid of wood. We lit the fire and within minutes the flames were at least 7ft tall and dangerously licking the electric cable above. Stick in hand, the cable was pulled aside to stop it from melting while more wood was added to the fire. It was real hot man.
After the fire subdued we cooled our pots with cold water. This may or may not have caused one of my pieces to crack from thermal shock. Carbon from the fire made the pieces black. After inspection Addison and I concluded its best to burnish the works for this firing method.
Both Raku and Pit Firing are similar in that a lot is left to chance. It would take years if not decades to master these firing techniques. I personally prefer the pit firing method and am eager to try this one again. What makes this learning experience so unique is that while I continue to discover more through daily hands-on making, I also get to seek advice from instructors that visit every so often, and the Addisons that decide to stay a while and be creative.