Adventures in Home Pit Firing
I've been trying very hard to focus on what I can do and not what I can't do. The former is constructive while the latter leaves me frustrated and motivationless. I will say though that I haven't gotten to do a glaze firing since late 2019 and that is leaving me feeling... not great, to be totally honest! Glazing is one of my absolute favorite parts of the ceramic process, especially testing new glazes and finishes. I'm dearly hoping that in Level 3 of New Zealand's lockdown I will get access to kilns in some respect.
But again, I'm trying to focus on what I can do. And what can I do when I don't have a kiln? A pit fire of course! Rather than spending time to dig a hole in one of my wonderful vegetable beds though, I've opted to use my fireplace. Why spend time wrecking a garden bed and getting muddy when I can just use a perfectly set up fire in the comfort of my lounge, right?
Following some advice from my tutor, Rob, about how to fire things in your own fireplace as well as my past experiences with pit firings, I started with two small pieces. One, a goblin that I managed to get bisced before lockdown and the other a small bottle I had thrown in my garage using the Polytech wheel I dragged into my garage on the eve of Level 4.
For the goblin, I had saved up some banana peels a few days before and kept them in a container with salt. I wrapped the goblin head up in the (very juicy) peels, and then wrapped the whole package up in some tin foil to keep it all together. The bottle I unceremoniously put into an emptied tin can.
The goblin did really really well! Infact, he acquired more color than any pieces I'd done in "proper" pit firings at school ever had. The bottle, though, did not do very well. In retrospect that should be unsurprising but I'll go over why.
First off, I didn't make sure the bottle was truly 100% dry. It had been sitting in my garage for over a week, and then on top of my mantlepiece for two days, but in a generally humid climate like ours that doesn't necessarily guarantee that all of the moisture was out. In addition, I put the goblin and the bottle in the fire once the fire was already going. Since the goblin had already been bisced, he did fine (save for one cheek being blown off, but that could also be from uneven heat distribution). The bottle, being greenware, was more brittle and sensitive and thus did not survive.
Lesson learned! Onto "pit fire" attempt #2!
This time I decided to do some small beads. I made 33 of them, one per day of Level 4 lockdown that we're in. This time I also used a slightly different claybody. While before I had just been using standard Mac's Mud Whitestone, this time I added in a bit of some found clay. There's a decently well-known bit of clay up at Whare Flats that people go and dig up occasionally, and I have a bucket full of it in my garage. It's quite a low-temperature clay and gives a gorgeous bright red color. It seems like a great suit to this style of firing, as the grog from the Whitestone adds enough extra strength to help the clay survive the firing while the Whare Flats stuff brings color, a bit more smoothness, and a slightly lowered firing range.
Since the beads are quite small, I didn't need to worry about drying them out as much this time. Being small means that the heat is much easier to distribute evenly. I also made sure to put the tin can I had placed them in into the fireplace before I lit it, so it would heat slower. I used the same method of salt-soaked banana peels for this firing. It went well, except for one thing...
What I didn't think of while I was packing the tin full of beads and peels was how the juiciness of the peels would effect the beads! What an oversight! The salt releases quite a bit of moisture from the peels while they sit in the container, and so I even poured that juice over the beads. I think I assumed the liquid would very quickly evaporate once in the fireplace. However it seems that wasn't quite the case. The liquid did permeate some of the beads and their integrity was compromised, leading to some of the beads being crumbly or even looking like they had melted to the tin can walls.
Another lesson learned! Onto "pit fire" attempt #3!
Okay, this one went much better. Combining the lessons of the first two firings really helped. First, I made sure the beads were as dry as possible. I left them out to sit in the sun for an entire day on my deck the day before. I also had them sit under the heat pump before lighting the fire. I packed them into two tin cans using a mix of dry onion peels and banana peels that I laid out on a towel to dry the night before. They were ever so slightly damp, but certainly not dripping with juice like the previous batch. I wrapped the cans up with tin foil and placed them in the back half of the fireplace, where I shovel the coals as pieces of wood burn down. This way they would get a good dose of heat throughout the firing process, and it would distribute fairly evenly around the cans as the coals are small enough to go around and cover the cans.
Very pleased how these ones turned out. I'm excited to try more dry materials to pack the cans and beads with to achieve new color effects. I'm also going to try waxing some of them, as I have heard that some people wax their pots that have been pitfired. But all of that is for another post on another day!