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Post by pinhead on Jan 10, 2018 7:56:57 GMT -8
That's a very nice-looking riser. What temp rating is your Duraboard? I see they make it for up to 3000°F which is pretty amazing.
Where did you get it and how much does it cost?
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Post by smokeout on Jan 10, 2018 7:57:20 GMT -8
I decided to make some changes again. I have been using 1" duraboard inside my 8" stainless steel riser, but only half way up. I was still getting some spalling, so I relined the riser all the way up. So effectively now I have a 6" dia 48" riser. I'm am totally shocked at how much faster the stove comes up to temperature and the heat exchanger is getting hotter too . It's holding steady at just over 1000F . I will refuel and see how long it can run on a fill up. youtu.be/EGM7YBSu2JYThis is exactly my experience and is why I'm leery of using a shortened riser as in the case of a cook stove. Every stove I've ever built has benefited dramatically from a taller riser. I'd like to see all Batch Boxes stick to the dimensions (including riser height) and if something shorter is needed, either don't call it a Batch Box or use the DSR. Sorry for the thread hijack. Good work and post a burn video! I will post a video as soon as I can. A viewable door on the front will make that possible and finish up the stove . I just got get off my butt and make it happen
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Post by smokeout on Jan 10, 2018 13:07:33 GMT -8
I ran the rocket with a full magazine of fuel, the second load since I fired it this morning. The stove was at 500F... once I got it loaded, the temp climbed to 900F give or take for two hours and then started to cool down as the fuel began to run out.(not all of the wood strips are the same length) I came back 4 hours later and the riser was at 250F, I dropped in some wood strips and off it went. If I can just get my wife to go along that easy. This thing is awesome.
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Post by smokeout on Jan 10, 2018 16:26:12 GMT -8
I tried over the past few years about six different feed tube configurations. This one works amazingly well. It's dimensions are 4-1/4" front to back and 6" across . The feed tube has about 50" vertical capacity and that includes the horizontal tunnel figured in. I had issues with spalling on the bottom couple of inches of the feed tube, so yesterday I cut it off and fabricated an all stainless steel box and welded the rest of the tube back on. You can see the horizontal connection weld on the tube in second photo. I get quite a lot of creosote build up inside the feed tube, but it drains down to where the pipe gets hot enough and the creosote dries and flakes off into the fire. Maybe this is just happen stance, but the square inches of wood I have burning is a pretty close match to the square inches of my riser. docs.google.com/document/d/12LpRxiqau65vISI8hjR38fIj7m8FpuzfUWIUjm9eHQU
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Post by smokeout on Jan 10, 2018 16:55:36 GMT -8
These photos are of the extra brick (I cut them to 1" thick) I used to build the horizontal burn tunnel. I guess they are a standard fire brick, the dimensions are 2-1/8"x4"x9". I had to modify my tile table saw by making a bracket to raise the motor an extra 1-3/4" to give room for the brick on it's edge to pass under the motor . So, I cut half and flipped the brick and cut the other half. I think the brick are a little higher grade than a standard fire brick because they aren't porous. Only one brick has cracked so far, it's at the mouth off the stove where the primary air comes in . I'm guessing one side is hot from radiant heat and the other side is cooler from the air coming docs.google.com/document/d/12ymhTge2KyCOAv_U18egiVp673-7H61aDBqjDunHWd8
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Post by smokeout on Jan 10, 2018 18:43:05 GMT -8
That's a very nice-looking riser. What temp rating is your Duraboard? I see they make it for up to 3000°F which is pretty amazing. Where did you get it and how much does it cost? Pinhead , I got it from Thermal Products in Georgia. 13$ per ft. I opted to go with 2300 to try and hold down costs. The riser gets white hot, so I figure the board is at its thermal limit.
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Post by smokeout on Jan 10, 2018 18:48:28 GMT -8
That's a very nice-looking riser. What temp rating is your Duraboard? I see they make it for up to 3000°F which is pretty amazing. Where did you get it and how much does it cost? Pinhead , I got it from Thermal Products in Georgia. 13$ per ft. I opted to go with 2300 to try and hold down costs. The riser gets white hot, so I figure the board is at its thermal limit. Pin head , it took exactly one sheet of 2'x4' dura board to line my riser.
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Post by coastalrocketeer on Jan 11, 2018 5:48:22 GMT -8
I'm pretty sure with that design you're an order of magnitude or two better than my "79% efficient EPA rating" Scandinavian smoke belcher! Even if that comparison is only "heat into structure per pound of wood burned" you're probably an order of magnitude better. At the "Pounds of CO and other toxic gaseous emissions per unit of heat into structure" two orders of magnitude would not surprise me one bit. I'm hoping the geopolymer section of this forum will soon be providing information in a format usable to produce suitable equivalents to these, and all the insulted castable and pre-formed dimensional refractory products. Those of us researching are hoping to take what Karl has shared already and make it organized, accessible, and coherent enough to the average lay-person, but with comprehensive enough information applicable the broad range of materials which can be used successfully, that virtually ANYONE in the world can make their own, in whatever embodiment best suits their chosen designs, from locally available resources. I couldn't afford the $10/sq foot I was quoted for this board or afford to buy enough to use what I need and sell off the rest at reasonable prices. There was an east coast vendor who only wanted $3-4/sq ft for it and I was prepared to spend $2-300 on a couple of cases of the 1", 2300F rated LD board, but the freight shipping requirement would have brought it right back up into the same price range. Among the many products that are apparently ubiquitous, except where I am, I found a locally available inexpensive feedstock to try geopolymers, with Karl's Clinoptilolite zeolite posts. I obtain it as "SweetPDZ" stalk freshener powder. I was already very interested in GP's, but did not have the access to a local pottery supplier of home center, to easily obtain mineral feed-stocks and aggregates, so was waiting for a work situation to need me to make the 4 hour round trip to the pottery supply house, at a time when I had some money to invest in a range of materials to experiment with. I am now experimenting with Karl's zeolite GP info and advice, and might have come up with a way to perform "burn tunnel and riser" suitable hardening of rock wool. It does not have the insulating value of LD board with my first test and technique, but is likely a bit stronger and probably can stand up to the feed area in J-tubes that burn only smaller sized wood like yours, and my desired design as well. The other thing that I think could easily be done with these geopolymers is to "paint" or "plaster" an inner refractory "hard face" onto softer more insulative refractories like CF Board or the MUCH cheaper blanket. (I recently aquired 100 sq feet of 1" for $2 sq. foot. I am heartened to see your design working with a "long tube" vertical wood feed. I am getting ready to coat this form with the next iteration of my own experimental interpretation of Karl's zeolite refractory GP mix around this combustible inner form... For info on my build and to see how it holds up over time, check out my zeolite geopolymer thread here, as I will be reporting whatever results I get there, good or bad. (Link to come with edit)
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Post by smokeout on Jan 11, 2018 12:08:44 GMT -8
Thanks for the info Coastal . I'm ready to do a casting so I hope you get it all figured out . lol I will be checking out your geo thread
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Post by smokeout on Jan 12, 2018 10:43:30 GMT -8
If anyone is interested, I recorded these temperatures on the feed magazine. 1000F at the base plate 1/4"x2" stainless angle 4" up 500F 1' up 240F 2' up155F 3' up 142F
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Post by smokeout on Jan 12, 2018 13:01:27 GMT -8
I made this insulated insertable/removable insert so that when I get the tunnel fire going , I can slip it right up to the location of the vertical feed tube. This helps reduce the the effective area of the horizontal tunnel. I haven't run it long enough to know for sure, but it appears as if it is making a difference. The second photo is the loaded feed magazine. The heat exchanger is hovering at 1000F and the exhaust flue is at 120F. docs.google.com/document/d/134ktvuEYe1msewNu9Ft_bPknxApO8wGXwIseSKrhR1w
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Post by coastalrocketeer on Jan 16, 2018 1:53:02 GMT -8
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Post by travis on Jan 16, 2018 17:57:25 GMT -8
Good job! Great to hear the experience of other builders. Keep it up
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