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Rammed earth bell for RMH?

 
Posts: 525
Location: Northern Germany (Zone 8a)
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hey...

what about making a "masonry"-bell from rammed earth for a RMH?

you could make a mold from boards and fill the void with clay-sand-mixture. and tamper it after every 4-6 inches. then add a metal-sheet on top and cob that in. you could leave the inner boards inside the bell as sacrificial mold.

i would expect that the rammed earth wall would not crack or shrink much, because in rammed earth you would use just slightly damp clay-sand.

how thick would that wall need to be?

my other thought was making a masonry-bell with clay-bricks. but that would take time for them to dry out (at least a bit).

i think, i should/could make a small freestanding test-wall. but i d like to hear your guesses on thickness.


thank you very much.
 
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Location: Cincinnati, Ohio,Price Hill 45205
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Hey, it took me a while to find the relavant links, but here are some pyros doing something very much like what you describe:

http://www.firespeaking.com/media/compressed_earth_blocks/
 
Tobias Ber
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thank you william...

rammed earth should work/perform quite similar to compressed earth blocks(CEB). the bell would be like one, big CEB.

but i m still wondering about the thickness of the walls. i guess something from 3-5 inches.
 
Tobias Ber
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ok, i made a "drawing". picture is from above.

step 1: make RE casing for cast core

step 2: make caste core from clay perlite with wooden, sacrficial inner form

step 3: make RE-Bell, make manifold from cob

step 4: add heat riser

step 5: add metal plate on top

step 6: cob metal plate in, cob around feed tube

step 7: install exhaust/chimney

step 8: plaster or paint with clay-paint (if neccessary)

step 9: maybe add mass-bench later
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