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Post by ronyon on Dec 1, 2016 21:20:59 GMT -8
Is a bell built of a single thickness of brick,rock,cement block,etc,sufficiently gas tight to be safe indoors? Or is another layer of masonry or metal or something needed?
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Post by satamax on Dec 1, 2016 22:51:18 GMT -8
Well, double skin is better. But you can get away with single skin. Few have done it here. One thing, i think bricks and plaster could be considered as double layer or skin.
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Post by matthewwalker on Dec 2, 2016 6:20:33 GMT -8
Single is fine in my opinion. If your heater works, it's always underpressure. If it's not, you have bigger problems.
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morticcio
Full Member
"The problem with internet quotes is that you can't always depend on their accuracy" - Aristotle
Posts: 371
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Post by morticcio on Dec 3, 2016 11:46:51 GMT -8
Both my heaters are single skin and used a clay/sand mortar. The first was rushed and only had a 1mm-2mm mortar bed. It leaked like a sieve when I first fired it from cold! Fortunately it was in a draughty shed so was able to open the doors until I patched the holes. When I dismantled the bell there were gaps everywhere so no wonder the thing leaked! The second heater was fine. I used a 4mm-5mm bed, ensuring the whole surface was covered. I intend to finish it off with a 10mm coat of clay/sand plaster.
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Post by ronyon on Dec 3, 2016 19:00:20 GMT -8
Thank you for your answers. Remind me,the sand in the sand and clay mortar is to reduce shrinking,right? No special sand is needed?
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Post by yellowdog on Dec 4, 2016 17:56:16 GMT -8
A sharp sand i heard is prefered over a rounded type like beach sand.,tighter stacking means more heat retenion. ?what ratio sand to clay gives most heat retention? I heard 3sand 1clay?? ?will adding rocks improve heat retention more? Like granite? any thoughts?
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