Hey all,
Just discovered the Walker Tiny Stove and I think I’m in love. I’m in Vermont, quite a long cold heating season, and I never liked the original
RMH, because it took up so much floor space, especially with the barrel clearances to combustible walls, and because I couldn’t see whacking all my cordwood up into ee-weenie
kindling and then sitting there to
feed it all day every day. (Had not heard of batch boxes; had not heard of vertical bells. If I had, those might have changed my calculation, but I like Walker’s design a whole lot better because of its compactness and especially because of its multi-use cooking areas!)
My cabin is 16x20 plus a couple gable rooms upstairs, with a staircase/utility closet/bathroom dividing the downstairs into kitchen and sitting areas. The existing hearth and chimney is in the sitting area, which is a bit inconvenient for cooking but I do it some already (mostly an endless pot of soup). Chimney about 15’ of metalbestos, up the center inside the house and out near the roof peak. So a plenty warm stack. Because of the dividing staircase/closet, the sq ft of sitting area is quite small and I tucked the hearth into a corner. So I would need to fit any built masonry stove in a space no bigger than 50”x50”, INCLUDING clearances from combustible wooden walls on two sides, so say 42”x42”. Presently using a Fisher Baby Bear cast stove, which works fine, but it’s a small cabin so until the most brutal mid-winter sets in I’m burning small smoky choked-down fires a few times a day and the house alternates between sweltering and frigid. (Plenty of insulation in the walls/roof/floor but the windows bleed heat and I think I’d go completely cabin-fever crazy without them.) Presently I go through 2.5-3 cord/yr, depending on the severity of winter. I’d be only delighted to drop that down some. Also would be happy to just shut off the propane to my range for the whole of heating season. (Right now I still often want to cook when the house is already too warm to add fuel to the cast stove, plus the Fisher has no way to bake but to drop foil-wrapped things directly in the coals.)
Yes, I do understand that even if I figure out most of my design on my own, with your help, and from the Riser-Less Core plans published under Creative Commons, I
should still probably send Matt a donation.
Here are my questions:
1. Looking at Matt’s design and the space I’ve got, I can’t possibly fit a bench bell but I might could fit a narrow vertical bell at the back. So: over the cooktop like he has it, down the one side like he has it (6.5”x20”x30”), underneath through the roasting
oven like he has it (24”x20”x10”), then up behind into a vertical bell about 6”x30”x50”. I can’t think of any reason air-flow wise why that wouldn’t work – it would come in around 44 ft2 of the 57 ft2 ISA allowed for a 6” system, and even if 6” of that final bell went to the exit stack it would maintain a minimum 5:1 CSA – but it seems like it might be good to have a bypass for getting started in the morning (or for quick cooking when the house is already warm) and I’m having trouble seeing where or how I’d make one. Seems like it would need to T into the exit stack of the bell, but that would be begging for smokeback?
2. I make bread, which Matt says works well in the downdraft section. AND I roast things, which Matt says works well in the underneath section. And gosh I look at all that vertical space in the final bell and think, wouldn’t it
be nice to set a bunch of drying racks in there, or even hang some jerky? (Though it might be too warm for that last.) However, seems like that many doors would be expensive, probably difficult to seal, probably too much immediate heat radiation into the room. Thoughts?
3. I understand the core needs to be IFB or ceramic fiber board. I’m curious about using
cob in the shell rather than brick. I’ve seen recommendations that the shell be two separate layers with a
cardboard spacer between, to make sure cracks don’t propagate through and release gas into the house. Seems like a good idea, but it also seems like it’d take up a lot of room and add maybe too much mass to radiate much, and also cob would be easier as 1 thicker layer than 2 thin, so is it necessary?
4. Our
local clay is a very different substance from the kaolin-rich Carolina clay I learned to cob with, and the local potters tell me it is low-fire only. I made a little test block and set it in the coal-bed of the Fisher for a couple hours. When I picked it out, it appeared intact at first, but I could crumble it with my thumbs. Obviously cob made of this particular clay doesn’t stand up to even mild firebox temperatures. Of
course it wouldn’t be in the firebox, it would be in the bell. So: How hot do the walls of the bell get? Because I might need to source clay from over the other side of the Greens if it’s too much.
4. Also, any advice on mounting airtight doors in cob?
5. Sigh … And about that suspended floor. The house is on piers with a sloped crawlspace beneath. About 3’ high under the area being discussed. Floor joists are 2x6 rough cut hemlock with 10’ spans between beams, plus a little extra blocking beneath the hearth for the (just a couple hundred pounds) weight of a cast stove. Grade soil a soft silty loam. Probably still fairly damp beneath the house (the
water table is high here, drain ditches or not; vapor barrier and gravel floor at present; still higher humidity than it ought to be) but at least it doesn’t freeze hard down there so no frost heave. Not especially easy access, just a crawl-hatch about 24” high by 30” wide. I use it for a
root cellar but always kinda dread hauling buckets in and out of there all hunched over. Miserable place to excavate, for sure. Obviously I’d have to do something. I do have a good supply of salvaged cinderblock, but it may be too old not to crack. Ideas? Would I be asking for trouble just to pile up cinderblocks on top the gravel and shove shimmed-up cross pieces spanning the joists above?
6. Hey, would this thing let me burn sappy resinous softwoods without gucking up the works? Because that’s mostly what I’ve got and I’m always
scrounging for clean-burning hardwood in a spruce swamp. That’d be a perk!
Thanks in advance for all your help.