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Post by Donkey on Jan 12, 2019 17:40:51 GMT -8
I forgot to say, we're only taking 5 participants!
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Post by Donkey on Jan 12, 2019 16:58:36 GMT -8
Hey y'all!
I'm co-teaching a workshop, we're calling it a Master Class, coming up on pretty short notice and I think it's worth looking closely at. It's 3 weeks, from April 8 - April 30 and it costs $3,000 (USD). It's primarily taught by myself, with Ianto Evans (the inventor of the modern RMH) and I hear the author of the Handmade Earthen Ovens book, Kiko Denzer plans to make an appearance.
The accommodations are rustic, in a small cob village (in stages of build) in the Oregon forest, in winter. It'll be wet and cold, but there should be lots of fire along with the mud, 3 meals daily, and basically camping indoors.
This 3 week course is an in depth look at Rocket Stove technologies. From simple cookers, through to Mass Heaters; Ltype, Jtype and BatchBox rocket feeds, we will discuss them all. We will cover materials usage, including home-made high temperature mixes, created from scratch. We will build 2 full working systems, as well as inspect and repair some existing stoves in order to learn how to spot common problems and fix them.
This course features: ~ Build a wood fired hot water system. This system is unique in that total safety is built directly into the basic design. Heating water with wood fire is normally very tricky and done wrong can be very dangerous, leading to steam explosion, maiming and death. We will build a double boiler system, which can never explode.
~ Build a scientifically advanced, but materially neolithic Rocket Stove Cooker. Rocket Cook Stoves are an important tool towards independent, sustainable living and can be incorporated into regenerative systems designs. We will explore how a sophisticated and very modern stove can be made from home-made, neolithic materials. Using these basic methods, a beautiful and useful stove can be built, almost anywhere, with almost nothing.
~Inspect and repair broken or unsatisfactory stoves. One of the best ways to get your brain around how Rocket Mass Heaters work, is to break a few and then fix them again.. These are already broken, we'll find out why and repair them.
Anyone interested? Call to register between 10:00 and 2:00 PST, Monday, Wednesday and Friday (541)396-1825
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Post by Donkey on Sept 3, 2018 9:58:39 GMT -8
How about a section for totally off topic community ramblings. One of the forums I frequent has an area where every Sunday the administrator starts a new thread with the date as the title, from there people can feel free to discuss anything they'd like. Many times it's about personal stuff like what the weather is like at their location, going to the doctor, recipes they are trying out, ad infinitum. It's a fun way to get to know the other frequenters of the forum. We could call it the 'fire pit', or 'camp fire', or 'camp stove', or whatever, it's just a place to ramble. ( kind of like this post ). The only thing off limits, other than profanity and the like, is politics. That can quickly poison the well and it is deleted immediately when found, a warning issued to the offending member via IM, and repeated infractions will get them banned. Part of the problem with this kind of thing is that I'm kind of an absentee landlord. I'm not round enough to make it really work. I would be glad to give someone responsibility over that area. I'd grant limited mod powers for that to some poor sucker.. Normally, that would be given to the requester, as punishment for being clever..
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Post by Donkey on Jul 20, 2017 20:38:13 GMT -8
Yeah.. Actually you're right, air channels all the way under the stove are better. Heat can get through the insulation and concentrate!! I was totally wrong back then. You can insulate under, but you need air space that can vent away under that! So now the recommendation is to use the same trick, bricks on edge with bridge bricks or something similar to create air channels under the combustion unit and perhaps also some of the bench/bell, depending.
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Post by Donkey on Jul 20, 2017 20:27:29 GMT -8
My goodness, a beast!
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Post by Donkey on Jul 20, 2017 20:20:49 GMT -8
Wood provides 6000 BTUs of heat per pound (yes, theoretically it's 7000 BTU per pound, but realistically I just use 6000) One BTU is enough heat energy to raise the temperature of one pound of water, one degree Fahrenheit.
How big is your pool?
Let's say I want to heat a large hot tub, which holds about 800 gallons of water. (it's capacity is really bigger than that but the heat exchanger and the people will displace some of the volume, etc.) Water is 8.35 pounds per gallon, so an 800 gallon tub holds 6680 pounds of water. Let's say the initial temperature is 68 degrees F. and I want to heat the water to 108 degrees F. (a change of 40 deg. F.) It looks like we can safely round off here (just call it inefficiencies in the tub and other bits) and make a local rule that one pound of wood can raise the temperature of our tub about a degree F. That gives us as a thumbnail estimate of around 35 or 40 pounds of wood for a sweet evening under the stars. Colder nights and colder water will require more wood. How many gallons of water are in an average pool??
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Post by Donkey on Jul 20, 2017 19:28:51 GMT -8
apollokit, That will certainly work, though you cannot turn a wood fire off so easily as a gas flame (unless you use wood-gas), as a result wood fired systems can become a bomb more readily. Be very aware of safety equipment for hot water systems and provide backups/redundancy. gretchen, That's exactly what I've been thinking. (or something like that) What if it was a metal bell chamber just under the water level, with insulated input (from the stove) and chimney on. Then the J-tube (or Batchrocket) can be outside the hot-tub/pool, easy to feed. fully insulated, etc. It would have to be bolted to the side pretty well, it's going to want to float out with some oompf.
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Post by Donkey on Jul 20, 2017 17:39:18 GMT -8
Do you have a chimney or are the gasses just exiting under the window at the end? (looks like some smoke on the wall hence the guess) There's no chimney. Exhaust goes out the first uncovered hot-spot. If all the hot-spots are covered, it goes out by the wall. The sides of the channels are formed with adobes, but the top is sculpted with cob, freehand. A thin plaster of perlite/clay is used to insulate the channels somewhat, though it's not on the ceiling of the channels, so it's likely ineffective but that's OK. The stove still works like a champ. I don't know what IFB is, sorry. I use perlite/clay because it's easy and inexpensive. I don't mind a slight loss of efficiency if I gain in utility and ease. My measure of a stove (or a building or anything else for that matter is "arse value"... The 80/20 rule is my greatest master. Good luck with it and don't forget to post your builds here!!
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Post by Donkey on Jul 15, 2017 20:50:03 GMT -8
This stove is all earthen mixes of one sort of another. The body is mostly adobe bricks with cob. It is insulated with a perlite/clay mix. First, we laid out the hot-spots. It was decided to stagger the hot-spots so that reaching to the back pot won't burn you. 2 Rocket J-tubes built side-by-side, the closest to the camera is an 8 inch stove, the one in the back, 6 inch. The only fired brick we used was for the top opening of the feed. It is my experience that if the top edges are adobe (cob), they will be wrecked over time by the wood. Bricks at the top edge of the feed will keep the firebox in good order. We added in wood storage underneath. This arch passes through to the other side. To make the heat risers, we placed stovepipe inside of adobe enclosures, packed between with a perlite/clay mix and then pulled the stovepipe out (metal is doomed!) Here, you can see that the risers are angled, so that the fires will be offset. We had some nice stone pieces that served well for keystones in our adobe arches. Test, a LOT. After the base was built, we ran the stove pretty much the entire time of building the rest. We insulated in and around the pot holders/hot-spots as much as possible with perlite/clay. Hot-spots are built to fit a particular pot like a glove. We built the channels like a Lorena stove; pots fit down inside the stove so that heat will flow all around the sides as well as the bottom. ALWAYS RUN IT WHILE YOU BUILD IT! This has been my philosophy since the very beginning of my adventures with stovery. It's treated me VERY well. Yes, you risk burns and smoke inhalation, but if you're paying attention, you can build superior stoves. Use your hands, ears and nose! They are your best guide. Though the potholes are shaped around a specific pot, reducers can be used to adapt to other pots and pans. This is as far as we've gotten with this stove. Not documented here yeat is that there will be another, much smaller rocket stove as well; a tiny, 4 inch twig stove will be build into the side. This way, if you just want to boil water for tea, you don't have to start and run the big-guns. There will also be 2 holders for a variety of beer-can alcohol burning stove that I like so much..
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Post by Donkey on Apr 6, 2017 16:49:17 GMT -8
I've been mulling this one.. My thought is to build a metal bell that goes inside of the tub and route the exhaust from a J-tube (or better yet a BatchRocket) into it.
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Post by Donkey on Jul 28, 2016 2:26:48 GMT -8
Cob building, speed and accuracy.
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Post by Donkey on Jun 10, 2016 9:07:33 GMT -8
Yeah.. Make small batches, a little wetter than you might think. The stuff goes off quickly, I've seen it set in the pot, while working. You will have to work fast to get the material on and smoothed to your preference before it sets. Drywall mud is essentially gypsum, though there is a lot in there that is NOT gyp. Karl could probably shed light on what all is in there, I don't know the details. Anyway, the drywall mud is FAR easier to use than traditional gypsum and if you don't mind the compromise in favor of ease of use....
I recommend that you experiment a bit before committing. Try it out on the same surface material (cob, brick, etc), you don't want ugly surprises on the final build!
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Post by Donkey on May 20, 2016 16:52:36 GMT -8
Yes. Glass angle has a LARGE effect. For solar gain, you want panes as perpendicular as possible to incoming light. There's always a small percentage of reflectance based on the thickness of glass as well, something about quantum spin.. Feinman talks about it in his "6 Easy Pieces" book.
A trick: In deep walls, like bale or cob; glass can be angled (tilted out at the top, in at the bottom) to exclude solar gain on a west wall while providing that view you just had to have..
On the practical side, angled glass can be a pain in the ass to deal with. The extra hassle can make it less attractive for some uses.
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Post by Donkey on May 19, 2016 8:43:49 GMT -8
On light passing through glass:
Depending on the thickness of the glass, and the color of the light, a certain small percentage is reflected off. Light that passes through the glass does so fairly well unaltered, then strikes objects behind the glass. When light strikes a surface like cob or something, some is reflected and some is absorbed. Light that is reflected can pass back through the glass, making objects inside visible to the eye. When light is absorbed into an object, it becomes heat energy, some of which is re-radiated back as infra-red. Glass is reflective to IR, which is trapped inside the space and is known as the Greenhouse Effect.
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Post by Donkey on May 15, 2016 20:49:05 GMT -8
Umm.. Actually, glass is rather poor at transferring radiated heat!! snipped from wikipedia: "Glass is transparent in the visible (approximately 0.4 µm<λ<0.8 µm) and near-infrared wavelengths, but opaque to mid- to far-wavelength infrared (approximately λ>3 µm)" This effect can clearly be seen using a Flir camera.. You can see your own heat reflection in windows.
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