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Post by fiedia on Oct 2, 2023 4:58:14 GMT -8
I drill a 13/64" hole and feed enough rope through to pull it tight and tie a knot in the front of the door to hold it in place. Smart |
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Post by foxtatic on Oct 3, 2023 7:37:31 GMT -8
treebased Thanks for the great documentation of this build. I am considering concrete blocks for a bell design too. Looks like you overcame the threat of concrete spalling with your interior coating of notched thinset (I assume refractory thinset mortar) followed by Blakite. And you mention that you ran it for two years before you got back into the bell to inspect it, finding no issues. It seems like the monolithic coating inside would crack since it would heat at a different rate from top to bottom and no gaps for expansion. But if you are not seeing any issues then I am encouraged! Did you take the thinset/blakite coating to the top of the bell with none of they typical second skin of firebrick above the core outlet? Have you found any downsides to building the bell this way? Would you do anything different?
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Post by martyn on Oct 3, 2023 11:26:46 GMT -8
Standard concrete blocks are not going to be very good at holding heat if that is what you want from your bell?
Ordinary concrete blocks are full of air gaps the whole structure is a matrix of gravel and air.
You can look for ‘high crush’ blocks that are used under lintels, as these have been vibrated and will be more dense but no where near as solid as bricks.
Of course you can use standard blocks, they just wont hold as much heat for as long as more dense materials.
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Post by treebased on Oct 3, 2023 13:24:50 GMT -8
treebased Thanks for the great documentation of this build. I am considering concrete blocks for a bell design too. Looks like you overcame the threat of concrete spalling with your interior coating of notched thinset (I assume refractory thinset mortar) followed by Blakite. And you mention that you ran it for two years before you got back into the bell to inspect it, finding no issues. It seems like the monolithic coating inside would crack since it would heat at a different rate from top to bottom and no gaps for expansion. But if you are not seeing any issues then I am encouraged! Did you take the thinset/blakite coating to the top of the bell with none of they typical second skin of firebrick above the core outlet? Have you found any downsides to building the bell this way? Would you do anything different? I used regular thinset for the notched mortar. I thought it would be ok since it was to be buried under 1/2" of Blakite, so far so good. The whole interior of the bell minus the floor is done the same way. |
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Post by treebased on Oct 3, 2023 13:35:06 GMT -8
Standard concrete blocks are not going to be very good at holding heat if that is what you want from your bell? Ordinary concrete blocks are full of air gaps the whole structure is a matrix of gravel and air. You can look for ‘high crush’ blocks that are used under lintels, as these have been vibrated and will be more dense but no where near as solid as bricks. Of course you can use standard blocks, they just wont hold as much heat for as long as more dense materials. I agree there's arguably better materials. A more skilled mason could frame it up and pour it solid. I did pour the blocks solid with concrete and rebar and used the thinner blocks to get faster radiant heat. I'm also using a grid of copper pipe wrapped in collectors on the top to add heat to my solar water tank which in turn heats my in slab radiant floor.
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Post by treebased on Oct 16, 2023 18:29:16 GMT -8
Did the first full load burn since last winter into a cold bell today. The chimney damper was smoking back bad out of both sides of the pipe where the pivot goes through. It works fine when the bell is warmed up. The doors, frame and seal to the bell are working great. No smoke back at all. Upper window is not as clean as I'd like, it might be a function of me getting used to the reduced air intake.
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Post by treebased on Oct 16, 2023 18:46:22 GMT -8
With the old intake, the top window would be clear to the top during this phase of the burn. Might need more air, or the top chamber is choked. Chimney topped out at 120, top got to 150 and the circulating pump kicked on at 130.
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Post by Vortex on Oct 17, 2023 0:26:11 GMT -8
Somethings not right there for sure, shouldn't be making all that soot. I forget all the changes you made but if you've reduced the primary air then I'd look at that. Also IIRC you changed from an insulated to dense afterburner and firebox, all that cold mass wont help, especially the afterburner, that really needs to be insulating refractories.
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amo
New Member
Posts: 11
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Post by amo on Oct 17, 2023 7:10:46 GMT -8
Hi Treebased. Thanks a lot for documenting your build.
What is the finish product and method you applied on the metal door ?
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Post by treebased on Oct 19, 2023 4:11:02 GMT -8
Hi Treebased. Thanks a lot for documenting your build. What is the finish product and method you applied on the metal door ?
One could also apply boiled linseed oil and bake it on with a propane torch for the raw steel "cast iron pan" look, although I'd recommend removing the scale first or using pickled in oil steel. The paint is a bit more forgiving on my amateurish looking welds.
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Post by treebased on Nov 1, 2023 5:23:12 GMT -8
I changed the removable vshaped floor to set back a bit farther from the air intake and replaced the solid front of it with expanded metal to direct air into the fire. I increased the top chamber opening about 1/8" making it 2 5/8" by 11 1/2" basically by removing the mortar joint. I made no changes to the intake. This in combination with the increased draw due to colder outside temps has it running as well as if not more consistently than it did with the insulating upper section. I may rebuild the upper section out of insulating castables next year as the soft firebrick slabs failed after only 2 seasons.
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Post by treebased on Dec 9, 2023 23:14:11 GMT -8
End of a mostly full burn into a cold box, 45F outside. Very little smokeback on startup and I choked the intake a bit until draw started. Top got hot enough kick on the water pump. Dirty burn vs heat capture
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