This is my first post on Permies. I live in Wales, Ianto's country, in South Wales. I read about Rocket Mass Heaters and Stoves about three weeks ago and at 10.30 at night. Went to bed a few hours later and couldnt sleep for wanting to make one straight away! I wanted to use reclaimed supplies in order to save items from waste and also to keep the cost down while I experimented but this is proving to be quite difficult as the items are not freely available. Natural clay is going to be a problem, is there a substitute for it? On a different thread someone suggests using cat litter but another post says that cat litter isnt clay The oil drums are probably going to be a little easier, my question with this is, how to light a fire in them to burn the paint off? The first one I tried was a smaller one, approx 25/30 gallon size and because the lid has to stay on, its a big deep bin and I think there was not enough oxygen to keep it alight I imagine the bigger drums would be even harder to keep the fire going? Or do I put it on a fire rather than light a fire in it? I thought that may distort it.
Hello Carol, welcome to RMHs. Clay is as simple as you can get, and doesn't really need a substitute. You could get it from http://www.claymansupplies.co.uk/ and other potters supplies, but if you look on google, you will find there are plenty of gardeners in South Wales who have to live with clay, so it's around. A bit of networking is needed. You could even try an advert on freecycle, or talk to landscape gardeners.
Hello and thanks for your help with the clay! The 30-gallon container was at the house we moved to years ago. A friend of ours who owns a farm may have some though? Do you live in South Wales, I could find out in a day or two. Im dying to try my hand at cob! Im going to have to think it through well though, as the rest of my family dont share my enthusiasm for permaculture. I may have to conceal it well and then do the new pair of shoes thing 'Oh that old thing, thats been there for ages'
There are a few people over your general direction I know of who are permaculture minded, so there's support around. When our present system collapses, being able to cook and keep warm will not seem so daft to your family.
Joined: Feb 10, 2009
Location: Okanogan Highlands, Washington
Some cat litter is Bentonite clay - tricky to work with, as it does expand and shrink dramatically with use.
Try a local pottery studio for discards, or as Roy said, local gardeners who may be in a clay pocket.
Remember, very little of the thermal mass is actually clay. Most of a proper earthen masonry mass is aggregate - sand, small gravel or rocks; there's usually some plain dirt, chalk, or silt; and straw - the clay is only the 10% or so that holds it together. If you have a local excavator, or well-drilling outfit, they may know where to find clay locally.
If you have a good local source for sharp sand or mixed sand and gravel, you are much further ahead than if you have only clay.
We've got several 'conventional' designs out there to evoke traditional European masonry heaters, to please those conventional relatives you mentioned. But if they like to pick on the 'abnormal' in order to feel normal, they probably won't stop picking just because they get cold or hungry. Human nature. Please yourself. Best defense is to be completely comfortable in your own skin, and getting muddy is a surprisingly good way to do that.
You might take a look toward the bottom of our 'shop' page, or some of the decorator ideas on the thread "Oil Drum in my Living Room."
Thanks for your reply Erica. Ive been experimenting with various set-ups in the garden and I am still completely fascinated by them! Im glad I am perfecting the technique outside before I plan and use one indoors. The one thing I find when I have been playing around is that I cant seem to keep the fire lit for too long. I was having huge problems lighting them at first but now use a piece of firelighter which seems to do the trick. But not too long after Ive lit it, it goes out again. It goes well for about 15 minutes though. What would be the most likely reason for that? Theres a slight possibility that the wood could be not quite dry enough. Also, would the height of the feed tube make a difference? Is there a formula for working out how high the tube should be in relation to the other components, possibly the heat riser? And also I havent used insulation in the seals and most of the chambers are made from storage heater bricks, which Im told arent that good at insulating. I dont think Im getting a real hot fire going. Every night I come in from the garden smelling like a bonfire! But Im going to persevere as I think the object of the exercise is to be able to light one and keep it going without the 'essence de burned wood'! Thanks to everyone for their help.
Joined: Jul 28, 2011
Location: Victoria British Columbia-Canada
Excavating companies, paving companies, masons, landscapers and anybody who engages in drain tile, foundation or sewer work are all likely to need to regularky dispose of clay. Just about any one who owns a machine that digs could have clay.Call them.
Carol Morgan wrote:This is my first post on Permies. I live in Wales, Ianto's country, in South Wales. I read about Rocket Mass Heaters and Stoves about three weeks ago and at 10.30 at night. Went to bed a few hours later and couldnt sleep for wanting to make one straight away! I wanted to use reclaimed supplies in order to save items from waste and also to keep the cost down while I experimented but this is proving to be quite difficult as the items are not freely available. Natural clay is going to be a problem, is there a substitute for it? On a different thread someone suggests using cat litter but another post says that cat litter isnt clay The oil drums are probably going to be a little easier, my question with this is, how to light a fire in them to burn the paint off? The first one I tried was a smaller one, approx 25/30 gallon size and because the lid has to stay on, its a big deep bin and I think there was not enough oxygen to keep it alight I imagine the bigger drums would be even harder to keep the fire going? Or do I put it on a fire rather than light a fire in it? I thought that may distort it.
I know our local Lowes store has bags of clay for sale and they aren't that expensive. Do you have a store similar to Lowes or Home Depot where you live? Could be you could obtain what you need there, as well as the sand with which to mix for the cob mud.
I'm going to be building one this summer as well and I too want to reuse old materials as much as possible, so I feel your pain. Upon research, I've found the pipes and fittings will be the biggest expense as I can scrounge free bricks and such here and there. I'm interested in the dimensions of the stove you are experimenting with in your garden?
You could try a small butane or acetylene torch to burn off your paint and other residues. You could even use a drill/sander attachment but it would take longer.
Joined: Apr 20, 2012
Thanks for your reply Jay We dont have Lowes or Home Depot in the UK Ive found some clay in the ground but just need to return to collect some. I took my dog the day I looked for it, it was on the opposite side of a river, and my dog wouldnt cross the bridge to get to it. So I had to leave empty-handed! Also, I have used mud from my garden to mock up the systems Ive done so far. Thanks to the people on these forums, who inspire us to just get outside and find something to make one with! Ive included some pics of my latest one. Ill try to talk you through the dimensions. Starts off with firebricks to form a feed tube of approx. 5.5ins sq. Then a burn tunnel made in the same firebricks of around 10 ins long and 5.5ins high. I have previously made the burn tunnels too long but find a shorter one works better with the other components Ive used. I placed a stovepipe, approx 6ins dia resting on the top edge of the far end of the burn tunnel, as the heat riser. I sealed the tiny openings around the pipe with mud. The stovepipe is 900mm long. I didnt want to cut the stovepipe as I may need it longer when I get to the actual system, so I needed to build up (I used storage heater bricks) around the base of the heat riser. This made up the height so that when I placed the drum over the riser, the top of the drum was approx 2 ins higher, which is about what they recommend. Then. I placed another length of stove pipe, again approx 900mm long, horizontally leading from below the opposite side of the riser as an exhaust. This is just literally resting on the slabs upon which I have built the whole thing. It has worked quite well. Had a good burn in the feed tube. I have previously had problems with keeping the fire lit. Today, when it looked as though it was dying back, I placed a firebrick over the entrance to the feed tube, just rested it on the sticks that were in there, and it revived it. After I lit it and while it was burning, I could see where any smoke was coming through the bricks and could mud the joints and, one by one, they all got sealed. The barrel got very hot. By the way, its a 30 gallon drum, rather than 55 gallon. I felt there was more smoke than I would have liked and thought it may be due to the exhaust not having any insulation? So I found yesterdays grass clippings and placed them all over and under the exhaust. I think it may? have made it slightly better. I would like to have a cleaner burn taking place. Although I felt it produced a lot of smoke, when I came in after playing around for about 2 hours, I didnt smell so bad of smoke. So I think there must have been steam mixed in with the smoke! I havent used any insulation anywhere, none in the mud/cob, or around the heat riser, I wonder if this is why I get a smokey burn? Anyway, have a look at the pics, I hope this has been of interest to you.
Joined: Feb 05, 2012
I've been looking for 30 gallon barrels for ages. Do you know a supplier?
Your fire may be smokey because of the size of opening at the firebox. If there is too much air going in it cools the gases and it makes them move too fast through the riser to burn completely. If you reduce the size of the opening, or stuff it with more sticks which will have the same effect, it might be cleaner.
Joined: Feb 10, 2009
Location: Okanogan Highlands, Washington
Absolutely, the lack of insulation on the heat riser will cause the problem you describe. The system is designed so it 'balances' when cold, serving kind of like the U-trap in your sink to slow the flow of gas. When you heat up the heat riser HOTTER THAN the barrel, and the barrel radiates heat and cools the exhaust down again to only a few hundred degrees, then you have a convenction-cell or thermosiphon 'pump' that keeps things moving. But if there is no insulation, soon the heat riser will radiate too much heat to the barrel, and they will equalize in temperature at a new, hotter, level. Turns it back into a U-trap again. Try the insulation.
Wet wood will also sometimes cause the problem you describe. Get the wood under shelter, use older wood (1-2 years under dry shelter), down to 15-20% moisture or less.
It's hard to keep fuel dry in a garden, the ground is moist and there's a tendency to set kindling on all kinds of moist surfaces. Make a dry box for your wood by the heater while you play. Any fire will go out if you put dry tinder to wet wood; the small kindling will burn up and the bigger, damp sticks won't catch. Water robs heat from the fire; steam evaporating from the wood robs even more; and air robs some heat as it flows past. The air adjustment makes me think you are just not getting hot enough in there at first - by 15 minutes you should be getting some serious ignition, and by about 30-45 minutes the bricks should be getting hot enough to bake fresh kindling dry or even ignite matchwood that is put down there regardless of whether there are still flames going from the other wood. The bricks getting hot is part of what helps the fire burn clean.
If possible, stay by the fire and tend it while it is starting. You can't feed in a lot of wet wood all at once without smothering it, so you have to gradually build the fire up at a rate that dries the next-size wood as you go. Stay by it until you have a full wood-box of sticks at least 1" thickness as your main fuel load - then check it again in about 30-45 minutes, as these burn down add 2" sticks, loading fresh wood behind the burning fuel so the fire is not interrupted by cold. When you get a nice set of chunky embers in another hour or so, put on a 4.5" or 5" round log to almost fill your feed. As the fire dies down, put tomorrow's kindling on a warm dry part of the heater. Once dead, close the opening with a couple of bricks so you don't get rain down the feed or dew at night.
Once you get it insulated, you can also just set the kindling inside the bricks of the feed (still warm from last night's fire, but after the embers have gone out), and let it dry out and pre-heat nicely. wood ash (when dry) makes a decent insulation. Sawdust mixed in clay slip does OK too, or straw dipped in clay/dirt slurry; both will burn out but leave a clay 'foam' behind.
I like how you have laid out the round base under the barrel. Maybe it's a woman thing - it drives Ernie nuts when I build my 'brick beehives,' he says nobody can follow it - but I find it much easier than trying to get bricks to stay square and match up course by course, only to bring it back to a round shape when I need to add the barrel. You've done an unusual pattern of pairs, when you do your indoor one you may want to alternate them so there aren't so many running vertical joins, but it's very pretty and symmetrical. Your garden soil looks marvelously dark.