What kind of gap should i leave between bricks and metal? Can i use thick corugated cardboard to achieve that gap, and pull it or let it burn before closing the top?
Cardboard against a metal surface which is heated from the inside isn't any good. Have done that, it turned out to be a very smelly business. Somebody else plastered a barrel when it was hot and already expanded and had good results with that. So either you pull the cardboard up in the process or heat the bell first before applying brick to it, I would think.
The core will be 220mm after. I won't keep this 7 incher. Not powerfull enough for the whole nearly uninsulated workshop. I can't remember, what is the guesstimate for power? 3kw gathered, for 1kg of wood? I think i can stuff in the 60 liters of the future firebox, something like 30 kilos of wood. 90kw! That's a monster I might be completely off!
Every kg of (completely dry) fuel should contain 4kWh, including the charcoal. It remains to be seen whether you will be able to stuff that much wood in the firebox. It will be almost never completely filled up to the top and there are a lot of gaps between the pieces. Also, you won't be able to yield more than 80% efficiency of that lot because you've got dry losses, chimney losses and more of that kind of factors. A bog standard 150 mm system firebox volume is about 30 liter and I've never been able to stuff more than 7 kg in that.
Well, the firebox for a 22CM heat riser is about 95 liters. That seems huge. With the excel spreadsheet i get 31,7cm width 47,5 height and 63,4 lengh. I'll reduce it to 60 in lengh anyways. 45 in height and 30 in width. Because that suits my materials better. So that's 81 liters so that's 18.9kg aproximately. 75.6kw. Madness!
I'm wondering if i need to glue the bottom slabs to the concrete flue elements. And how should i glue the side slabs? Refractory mortar? It will be exposed to heat from conduction through firebricks. As the box showed here will be lined with the firebrick slabs i've bought the other day. The top will be cast iron cooktop. Do i make a metal frame to hold all this, and attach the door to it?
I have to find hinges too then. I think i'll make the primary air with a gap all around the door. That gonna be complicated to respect the 20% doing it that way. I've tried the door in front, it fits nicely. Nearly spot on as for the size.
I gonna assemble thoses four doors as a single flat one. Which i'll fit to the first bell, in front of the heat riser, so i can assemble the whole thing, and clean when required. The bottom pipe from bell 1 to bell 2 will be embeded in concrete between the firebox and the bell actualy in place i think. Thoses two options are not for sure right now. If anybody sees a better option?
Last Edit: Oct 26, 2015 14:05:49 GMT -8 by satamax
Im trying to remember where I read about someone using corrigated card board to make an expansion gap around a heavy gauge metal riser surrounded by insulating concrete, or cob, not sure. as I recall, they just left the card in their, figured it wasnt doing any harm, or possably helped with some insulation value. I think they covered the card with a reasonably thin layer of plaster/clay or something, then let that harden, to prevent it from getting saturated and crushed by the big mix. sorry I cant be more helpful. donkey would know what to do
I did that. I used the cardboard as a "slip joint" between the steel duct and the clay/perlite riser. I fired the stove a couple of times to sufficiently dry the riser in order to safely extract the steel duct. Once the duct was removed I could fully fire the stove and harden the riser.
Riser length should be between 8 and 10 times base figure. Smaller systems needing the higher end of the scale, larger systems could get away with the lower end. As I see it, yours would be about 9.5 times base at 150 cm, so this should be perfectly adequate.
Wondering if i use this cast iron top. It's either too short or narrow. I could always stick a few firebricks to the sides to stop it moving. And Use rockwool for the joint. But i'm still wondering, i think i gonna mortar the sides. But should i leave a bit of a gap between the air entrained concrete sides, and the refractory liner? I gonna use the tank on top to hold the air entrained concrete slabs on top, i will weld two little lips bellow. Still thinking on how i will make the P channel. And still looking for some cast iron to do a bottom bottom secondary air under the slants. I went to buy 1.5 tons of sand, and 10 bags of cement, to make a mortar, which will fill the holes in the salvage bricks i have. I realy need to make the top barrel/Bell's door too. I will use the same outside flue elements (grey ones on the bottom) inside the bell, to hold the insulation outside the heat riser, and to add a smidge of mass. And i will fit two of thoses on top of that bell, and fill theses with concrete. I need to sand the first bell too. Lotsawork to do!
If there's readers. Would you think a 7cm thick brick layer between the two bells would be worth anything as mass? Or should i make theses touch?
The contact surface would be 50cm wide, by 125 cm high. And if i fill that space with mass, i would get about 105 more kilos of mass, for heat storage.
You know my walls are made out of thoses hollow clay bricks. I've run the stove all day long or prety much today. The big black bell touches that wall or, nearly , as the wall or the bell are at an angle, they're in contact at the bottom, and i have 2cm gap on top. The wal next to the big bell was realy hot to the touch. And on the other side, after 8 hours of burning or so, it wasn't even lukewarm. Good as far as insulation goes. But if someone had an idea on how to fill up that wall with concrete or sand. I would be gratefull.
I forgot to say, a friend laid the pipes this way, he had the idea to put theses that way at first. I wanted to use only one elbow originaly. Tho, that will increase the drag. It will work better as for the layout.
He set that up, while i was cutting the other tank. I came around that corner of the workshop, wanting to check measurements. Put my hand on top of the tube, and felt the draft! Take my lighter to it! It blows the flame off. Good news!
flybywire: Glass window from an old washing machine is designed to take high temps. Cheap solution to your need.
Jan 27, 2019 0:10:58 GMT -8
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Feb 7, 2019 0:11:23 GMT -8
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Feb 7, 2019 0:12:22 GMT -8
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Mar 11, 2019 18:56:41 GMT -8
jlmtech: GADGET: CONSIDER USING A JET PUMP INSTEAD OF A BLOWER FAN TO INDUCE DRAFT; NO CLOGGING.
Mar 26, 2019 8:19:28 GMT -8
michaelegan: i am unable to open the sketchup files on my mac. I used sketchup a few years back but apparently the company now requires a subscription. does anyone have any advice/instructions on how to use the program or how to view pictures without spending money?
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Aug 23, 2019 13:33:44 GMT -8
topbaza: hi everyone, been searching all over net and this is were i need to be i think!!
Sept 28, 2019 6:16:25 GMT -8
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Sept 14, 2020 7:26:15 GMT -8
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Sept 14, 2020 7:29:27 GMT -8
deadstarsstillburn: Hi there. I was directed this way by folks on the Permies.com website and am hoping I can get some information on how a total newbie can get started designing, siting, building, and not-dying-in-a-horrible-house-fire with a new RMH in a 160-year old home
Oct 21, 2020 6:52:10 GMT -8
deadstarsstillburn: The people over there recommended either a 6" batchbox or an 8" J-tube. I don't know what those are but am going to try to figure that out. What I need is a blueprint that I can scale to fit the need for my house. I have something likne 5000 square feet
Oct 21, 2020 6:53:00 GMT -8
deadstarsstillburn: but I do not need to heat all of it by any means. probably only need to heat half of that, maybe less.
Oct 21, 2020 6:53:15 GMT -8
deadstarsstillburn: moreover, the house has 3 storeys (large attic) so I assume if I get very efficient heating on the ground floor, that will go a long way toward heating the upstairs as well, no?
Oct 21, 2020 6:53:59 GMT -8