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Post by pinhead on Jan 22, 2017 11:16:53 GMT -8
We worked on the stove on Saturday and ran out of clay... Went out to find more sand and clay and hit the mother load... Basically an unlimited amount of each. The clay is very light gray - probably as pure as potters clay. There's an outcropping on the side of the hill less than 100 yards away from the house! It's 6 feet thick by probably 50 feet long.
Working with the new clay is a lot tougher than the stuff we've gotten used to working with; this is so pure it doesn't like to come apart and mix with the sand. We had to get rougher with it, using a hoe and a lot more water than usual. Once we got the clay-sand mixed up - it had to be extra watery to get the clay to come apart - we added ash to both help it harden and to soak up the extra water. We'll see how it holds up - hopefully 1:3 clay to sand is a good ratio.
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dkeav
New Member
Posts: 27 
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Post by dkeav on Jan 24, 2017 15:37:02 GMT -8
Some people would give you strange looks for shouting "Eureka!" at finding a clay outcropping...but not us.
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Post by pinhead on Jan 25, 2017 12:13:07 GMT -8
Some people would give you strange looks for shouting "Eureka!" at finding a clay outcropping...but not us. When I accidentally ran across it I literally ran into the house to tell the wife.  I was especially excited since clay was going to be the limiting commodity; the closest source I knew of was ~15 miles away and the ground has been frozen so I couldn't just dig a hole in the ground. |
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Post by pinhead on Jan 31, 2017 6:31:52 GMT -8
I finally got some work done on this project. www.facebook.com/media/set/?set=a.10154992139891974.1073741834.559871973&type=1&l=c6e07d689bThe secondary bell is limestone. The mortar is clay, sand, and ash. Riser size is 6 inches. Riser insulation is one inch of ceramic fiber blanket inside an eight-inch flue pipe. I am absolutely amazed at how well the ceramic-fiber insulates the riser; draft takes off instantly and the 8-inch pipe gets appreciably hot but not nearly as much as I had assumed with only one inch of insulation. I'll likely wrap the bottom half of the riser with an additional 3 inches of rockwool insulation if the geometry allows. The only reservation I have is whether the bare ceramic-fiber will eventually "blow" out due to the fierceness of the turbulence and draft in the riser. Only time will tell. |
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Post by pinhead on Feb 6, 2017 7:37:16 GMT -8
I got a lot of work done over the weekend but, unfortunately, most of my pictures didn't turn out. I got the last couple of pics I took of the bypass damper, though. The straight-through portion of the "tee" goes to the bottom and top of the bell, respectively, and the transverse entry/exit of the tee goes to the chimney. The top of the tee is capped with a homemade damper. The damper is wholly homemade, using thin sheet metal and an electric fencepost. Bypass Damper |
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Post by Jura on Feb 6, 2017 8:50:21 GMT -8
Have U already solved the issue of hardenig the structure? |
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Post by pinhead on Feb 6, 2017 9:23:24 GMT -8
Have U already solved the issue of hardenig the structure? I didn't build it quite like the picture - I put the ceramic fiber blanket inside an 8-inch flu pipe, without the mineral wool. www.facebook.com/photo.php?fbid=10154992096951974&l=3e4ec1844fI'm going to run it as it is and see how it lasts. Luckily the riser is easily removable if it needs to be rebuilt. |
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Post by Jura on Feb 6, 2017 9:59:42 GMT -8
Do I get it right? you finally didn't apply any hardener to ceramic fiber blanket? I browsed the facebook album just a moment before postimg my former question but didn't see the photo of the riser in there (I remember the one with icon thou :-)) Did U add it later on? or () should I give today up all activites requiring mental concentration ;-)? |
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Post by pinhead on Feb 6, 2017 12:43:29 GMT -8
No - I didn't apply any hardener. The ceramic-fiber blanket is rigid enough by itself to stay inside the form of the 8-inch flu pipe.
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Post by pinhead on Feb 7, 2017 8:14:35 GMT -8
I got a lot of work done over the weekend but, unfortunately, most of my pictures didn't turn out. I got the last couple of pics I took of the bypass damper, though. The straight-through portion of the "tee" goes to the bottom and top of the bell, respectively, and the transverse entry/exit of the tee goes to the chimney. The top of the tee is capped with a homemade damper. The damper is wholly homemade, using thin sheet metal and an electric fencepost. Bypass DamperI got the chimney hooked up and the stove sealed up well enough to give it a test burn last night. One thing I'll say is I'll never again build a Batch Box RMH without a bell bypass; with an open bypass the stove is rudimentary to light without smoke-back, even with everything still being sopping wet. It was neat opening and closing the bypass and feeling the chimney pipe temperature go up and down - I could open the bypass and the flue pipe was warm to the touch, then close it and in a matter of seconds the pipe temp dropped to the temp of the mass - about 40°F. But it looks like I got the stove up and running just in time for the weather to warm up - it's supposed to be in the 60°F range for the next 10 days. I guess I'll just do my burning/testing at night when it's closer to freezing... |
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Post by pinhead on Feb 11, 2017 15:49:44 GMT -8
I got the stove semi-finished - all sealed up and burning last night. Here are the pics: www.facebook.com/media/set/?set=a.10154992139891974.1073741834.559871973&type=1&l=c6e07d689bChimney height from bell exit to top of the chimney is roughly 12 feet. The upper six feet or so is a homemade "double wall" pipe going through the roof of the cellar. Outside is a clay chimney lined with reflective radiant barrier (8-inch ID) and a 6-inch stovepipe running down the middle, creating a roughly one-inch gap. I may trade the bare stovepipe with double-wall pipe to give me an effective "triple wall" chimney, or might replace the radiant barrier with an inch of rockwool or similar insulation. Everything is still wet - and it wasn't very cold outside so the draft wasn't super strong. Nonetheless, the face of the barrel at peak burn was a consistent 750°F. Closing the bypass during the peak of the burn tended to cause slight smoke-back through the top of the door which is probably expected; the exhaust pipe temperature dropped to 85°F (outside temp was ~40°F). With the bypass open, the exhaust pipe stayed steady at 135°F. I plan on inserting a temperature probe into the exhaust to get a feel for the actual temperature of the gasses (vs the temperature of the pipe). The mass is still appreciably wet, though, so the low-draft condition is expected under these circumstances. I recorded a short video overview of the stove. After a burning a full load, reloading - and a thoroughly wet mass - I closed the bypass to see how the stove would respond to the reduction in draft. Barrel temp was ~550-650°F and flue pipe temp was 85-95°F at this point. I ran out of space on my phone before I was able to get back to the cellar and open the bypass to monitor the exhaust temperatures which peaked around 180°F with the bypass open. www.facebook.com/djptacek/videos/10155022519916974/This morning I checked temperatures before I went to work and the limestone mass had risen to ~95°F and the cellar was comfortably warm.  Now it's 70°F outside and I won't need the stove for a while. |
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Post by pinhead on Feb 14, 2017 10:02:15 GMT -8
I wanted to run an experiment so I lit the stove last night while cleaning the cellar out. I let the first load burn down to coals and then added another couple of good-sized logs before I came in for supper around 8:30pm. When I went to check on it this morning, the mass had risen to ~95°F (same temperature as the previous "test"). The unexpected part, though, is the barrel was ~100°F as well. I guess that means I made a large enough transition into the bell - as the entire structure is acting as a single bell, with the barrel at the top.
I suspect the tertiary air was getting plenty of pre-heat; before I re-loaded the stove last night I shut off the lights and noticed that approximately half of the length of the p-channel was visibly glowing dull red (during the coaling phase).
I took some time and re-lit the stove this morning to see how it acts with a fairly warm mass. With the bypass open the flue pipe quickly rose to ~180°F. After lighting the stove and closing the door, I left the bypass open for another few minutes to make sure the firebox got good and hot before closing the bypass. I closed the bypass and the flue temperature quickly dropped to around 90°F. There was a lot of visible steam in the exhaust and a very slight smoke smell (very slight). I didn't think to check the smell with the bypass open, however, to see if increased draft would have cleaned up the exhaust. With the bypass closed there was still the roar of a flame-filled heat riser so I suspect the smoke disappeared shortly thereafter (once the P-channel and riser warmed up).
I won't be able to check any temperatures until I get home from work, though, which will be approximately 10 hours after I re-lit the fire. This is the first burn in the stove with a warm mass.
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Post by pinhead on Feb 15, 2017 6:19:18 GMT -8
When I got home yesterday I checked the temperature of the mass and it had dropped to ~85°F. I suspect that since the cellar walls are a pretty consistent 45°F, this will be a pretty consistent temperature-time span. And, of course, a burn video. www.youtube.com/watch?v=OG7FqSex7BU |
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Post by gugaiz on Mar 3, 2017 14:40:55 GMT -8
Hi pinhead, I am about to build a heat riser in a similar way you did.. ceramic fiber blanket inside a tube. I was planning to use kanthal wire to secure the blanket and one row of insulated fire brick on the bottom (to receive the flames). Have you open up you stove? it will be wonderful to know if the ceramic blanket is still in place. Would you recommend this technique?
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Post by pinhead on Mar 15, 2017 11:50:31 GMT -8
I've looked into the heat riser through the throat of the stove and I can't see any destruction or distortion of the riser/ceramic insulation.
I haven't removed the barrel, however, to inspect from above. Given the high velocity behind the throat, with reduced velocity elsewhere in the riser, I expect the wall opposite of the port would be the first place to see damage if any damage is going to occur. Thus far, I haven't noticed any.
I've only burned the stove maybe a couple dozen times, though, so I can't guarantee the effectiveness of this design long-term without further testing and time.
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I was especially excited since clay was going to be the limiting commodity; the closest source I knew of was ~15 miles away and the ground has been frozen so I couldn't just dig a hole in the ground.
