I have a small (14x16) camp in Jonhsburg NY. It’s well insulated. I put a small wood stove in it and it’s way too much heat once the place is warmed up no matter how cold it is outside. If you tend it once or twice an hour there’s only one window open. Of course it goes out at night and if the propane heater is off it gets cold in there. The stove is a military surplus tent heater, it’s rated for coal and pretty tight. The chimney is double wall SS and I double insulated the thimble with some kind of ceramic wool I bought for that purpose. I have a smoke and CO detector as well. I bought a few bags of nut at the local TSC, cut an 8” piece of stove pipe down to 9” and blocked off most of the internal grates in the stove till there was a 6” hole in the middle of the stove. I put the stovepipe right over the hole and fired it up yesterday afternoon. It got pretty hot in there till the fire settled down but after that it gave out nice steady heat all afternoon. It was still kind of hot in there but the temps were in the low 40s. There was still plenty of heat left in the coal when I went home for the night and I only put about 4” of coal in it. There’s little doubt in my mind this will keep the place warm all night in any weather. The top of the pipe where it joins the double wall just barely sizzled a drop of water. I have real thermometer is on the way. Opinions and suggestions are always welcome.
You may want something a little heavier than the stove pipe as that could melt. And if it works real good for a while you may even want to make a cylinder out of refractory cement for the coal. Maybe find a larger size pipe to go around the one you are using (cardboard would work) and pour that inside between the two. Hope that made sense.
Yes, as warned (and expected) the stove pipe didn’t last. I had some large firebricks lying around so I layed them on their side and arranged them in a square in the middle of the stove. They're held in shape with a large hose clamp. I also installed a BD. It was hard to find a 4" one but Dickenson Marine makes a very nice one. I also made a poker to stick up through the grates and I get a lot more ash cleared out that way rather than just shaking. I spent last night up there. It got down to about 14°f and it stayed about 73°f inside with a window cracked an inch. I'll need learn how to set the controls for a little slower burn. I had to shake, poke and fill once about 0200 and it still had plenty of life when I woke up. I'm quite happy with the results.
The thimble should take the heat ok; but you do have a valid point about being banged around. Like I said "just a thought". However I do like your idea and think it's pretty clever. Still trying to talk to my son into a coal stove in his camp, but he is stubborn! Jim
I just upgraded the coal/wood stove at camp. I went from a square pattern of fire bricks to a hexagon pattern. The new pattern on paper is about 25% larger but since it sits up higher on the concave grates it holds more than that. I also put a bit of stove pipe inside and below the stove gas exit to keep more heat in the stove. I have yet to see how that works but I can pull it out if it doesn’t. I also sealed it up better. There’s a layer of stove gasket between the top and bottom half and high temp silicone on the inside of the ash door. I was prompted to do this last winter when I wanted to spend a very cold night there. I got there around 3pm, it was about 6°f and the dwelling was ~15°f or so. By twilight it was 40°f inside, -4° outside and I bailed for home to the fully loaded Vigilant. I know the original configuration will keep me warm in any temperature, it’s just getting the place warm I want to fix. I’ve got propane heat and it was on but it’s not vented and I try to use it as little as possible. I have 2 CO detectors, a smoke detector and the propane has a low oxygen safety on it.
Spring chores. I needed a wood shed so I built one. As soon as I got done I realized I needed dry, outdoor storage so I’m building an extension. I should have realized it in the first place, it would have made the build easier. The black flies were bad yesterday too.
I probably won't be able to give a full report for months but it should put out more heat and be more controllable. The left side is about 1/2 full of wood and I'll get up there this week and put some Oak chopping blocks on the right side. It's pretty well protected from the wind there but I've seen it blow hard enough to do some damage.