Feats of clay
Sep. 22nd, 2020 15:59![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
torquillEvery so often, I come into the living room and I find something new on the table by my chair. Sometimes it's a cartoon, or a couple of magnifiers, but often it's a book. A week ago it was "Your Out Of Control Ferret" (how to train a pet ferret), but today it was a book on making clay bread ovens.
I've been exploring the options for various types of wood heat, with an eye toward a sustainable non-electric heater for the proposed greenhouse. I've looked at rocket stoves, rocket mass heaters, traditional freestanding woodstoves, and masonry heaters. Rocket stoves and rocket mass heaters take a decent amount of engineering and know-how, plus they need things like metal barrels and firebrick to hold up to the really high temperatures involved... masonry heaters still should be floored in firebrick, but they're much more like woodstoves in construction, and they take full-sized logs rather than constant feeding with sticks. I've been rolling all of this around in my head with thoughts about chimneys, J-tubes, hypocausts, draft passages, and cleanouts. Most of the advice around greenhouse heaters is for things like 30'x100' poly tunnels and such, so I'm having to kind of find my way for my little 8'x14'.
And now here's this book, with tiny (in some cases 12" across) single-chamber cob ovens. I had already been looking at cob, thanks to rocket mass heaters, and we do have everything we need here -- clay soil in the lower pastures, sandy ashy soil in the upper reaches, plant material that can be chopped and mixed in, and even some dry potter's clay I can use for a nice smooth finish. We have some pieces of chimney brick for a firebox, and some pieces of concrete for a base; a few firebricks for the floor aren't expensive. It's mostly a question of design. I admit, the book made me realize that there's no reason I can't build a small oven into the mass heater I build for the greenhouse: the opening for the firebox would be on the outside anyway, I could just put a chamber above it. If I'm firing the heater, I could throw a casserole in there.
It also made me realize that time is the only limitation I have if I want to make a little 12" one-chamber oven while waiting for a new range. It would be nice to be able to bake potatoes properly, and do a batch of muffins or a few cookies. These little ovens can be built in an afternoon and fired the next day, so it's not even a huge time-sink. I'd just need to figure out where to put it, and how to protect it from the weather.
Jenny had another idea. She suggested I reconfigure the old tumbledown greenhouse into an outdoor kitchen, using the supports to put a roof over the otherwise open structure. I was planning on disassembling the greenhouse completely and repurposing the materials, but I see her point -- the side yard there is conveniently placed close to the house, it has the picnic table already, and it would be a nice place for a garden party. An outdoor kitchen is a very good idea. With some counter space and a simple oven -- maybe even a griddle surface, like the way the woodburning cookstove is designed -- plus a charcoal grill, you could cook just about anything. Perfect if people are camping in tents on the front lawn, for example. I'm undecided whether to add a proper sink or simply rely on the standpipe by the back entry.
I'm still toying with the thought of a wood-fired hot tub behind the Annex. Goodness knows, even if we run out of big branches and trees to cut on this property -- the alders grow fast everywhere, and there's the wild property east of here -- single-chamber ovens and rocket stoves use small-diameter fuel, which we're unlikely to ever run short of. Apparently you can even heat the ovens with dried thistles (and use the fine ash for soap). So we're not likely to ever run out of burnables here. If I can keep the fuel dry and seasoned, which is especially easy with kindling, we might be able to get away with using the oven or hot tub during burn-ban season, though not when there's a red flag warning on. Spark-guards and irrigated surroundings can only do so much. But fire weather here is only a month or two, leaving plenty of nice weather to do outdoor cooking and soaking if I can keep the smoke to a minimum. Proper chimney design should also help.
If I get a little extra time around the edges, I might try building that 12" potato-roaster, even if it is left to the mercy of the weather. It would be a good experiment.
I've been exploring the options for various types of wood heat, with an eye toward a sustainable non-electric heater for the proposed greenhouse. I've looked at rocket stoves, rocket mass heaters, traditional freestanding woodstoves, and masonry heaters. Rocket stoves and rocket mass heaters take a decent amount of engineering and know-how, plus they need things like metal barrels and firebrick to hold up to the really high temperatures involved... masonry heaters still should be floored in firebrick, but they're much more like woodstoves in construction, and they take full-sized logs rather than constant feeding with sticks. I've been rolling all of this around in my head with thoughts about chimneys, J-tubes, hypocausts, draft passages, and cleanouts. Most of the advice around greenhouse heaters is for things like 30'x100' poly tunnels and such, so I'm having to kind of find my way for my little 8'x14'.
And now here's this book, with tiny (in some cases 12" across) single-chamber cob ovens. I had already been looking at cob, thanks to rocket mass heaters, and we do have everything we need here -- clay soil in the lower pastures, sandy ashy soil in the upper reaches, plant material that can be chopped and mixed in, and even some dry potter's clay I can use for a nice smooth finish. We have some pieces of chimney brick for a firebox, and some pieces of concrete for a base; a few firebricks for the floor aren't expensive. It's mostly a question of design. I admit, the book made me realize that there's no reason I can't build a small oven into the mass heater I build for the greenhouse: the opening for the firebox would be on the outside anyway, I could just put a chamber above it. If I'm firing the heater, I could throw a casserole in there.
It also made me realize that time is the only limitation I have if I want to make a little 12" one-chamber oven while waiting for a new range. It would be nice to be able to bake potatoes properly, and do a batch of muffins or a few cookies. These little ovens can be built in an afternoon and fired the next day, so it's not even a huge time-sink. I'd just need to figure out where to put it, and how to protect it from the weather.
Jenny had another idea. She suggested I reconfigure the old tumbledown greenhouse into an outdoor kitchen, using the supports to put a roof over the otherwise open structure. I was planning on disassembling the greenhouse completely and repurposing the materials, but I see her point -- the side yard there is conveniently placed close to the house, it has the picnic table already, and it would be a nice place for a garden party. An outdoor kitchen is a very good idea. With some counter space and a simple oven -- maybe even a griddle surface, like the way the woodburning cookstove is designed -- plus a charcoal grill, you could cook just about anything. Perfect if people are camping in tents on the front lawn, for example. I'm undecided whether to add a proper sink or simply rely on the standpipe by the back entry.
I'm still toying with the thought of a wood-fired hot tub behind the Annex. Goodness knows, even if we run out of big branches and trees to cut on this property -- the alders grow fast everywhere, and there's the wild property east of here -- single-chamber ovens and rocket stoves use small-diameter fuel, which we're unlikely to ever run short of. Apparently you can even heat the ovens with dried thistles (and use the fine ash for soap). So we're not likely to ever run out of burnables here. If I can keep the fuel dry and seasoned, which is especially easy with kindling, we might be able to get away with using the oven or hot tub during burn-ban season, though not when there's a red flag warning on. Spark-guards and irrigated surroundings can only do so much. But fire weather here is only a month or two, leaving plenty of nice weather to do outdoor cooking and soaking if I can keep the smoke to a minimum. Proper chimney design should also help.
If I get a little extra time around the edges, I might try building that 12" potato-roaster, even if it is left to the mercy of the weather. It would be a good experiment.
