jonasp
Junior Member
Posts: 102
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Post by jonasp on Jan 18, 2023 1:10:56 GMT -8
Hi,
I was thinking if there's a good reason to not built the ceiling of the bell out of vermiculite boards.
The pro's I'm thinking about:
-easier to make it detachable if needing to change something in the bell
-insulating material
-easier to install the ceiling vs T profile metals and firebricks with ceramic wool
-more warmth in the walls vs ceiling
cons:
-not accumulating the warmth in the roof so less ISA
-less sturdy maybe?
-..
looking forward to hearing some other opinions!
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Post by martyn on Jan 18, 2023 3:25:59 GMT -8
Maybe, there seems to be a few grades of vermiculite around depending on where you live, some are longer lasting than others.
Also it appears there is no need to have an insulated roof in a batch box and it also appears that you could have a slightly arched roof thus enabling two bricks to span the roof.
If you do try vermiculite you could also try coating it with zircon as this will extend the vermiculite life and possibly help by radiating back some heat.
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jonasp
Junior Member
Posts: 102
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Post by jonasp on Jan 18, 2023 4:06:12 GMT -8
Maybe, there seems to be a few grades of vermiculite around depending on where you live, some are longer lasting than others. Also it appears there is no need to have an insulated roof in a batch box and it also appears that you could have a slightly arched roof thus enabling two bricks to span the roof. If you do try vermiculite you could also try coating it with zircon as this will extend the vermiculite life and possibly help by radiating back some heat. I'm probably going the safe route and use double layered, firebrick ceramic wool and brick. It was something that popped in my head and wanted to ask other people opinions. I've seen your test with zircon and I already have vitcas vermiculate boards and vitcas zircon for the afterburner (going for the vortex core)  |
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Post by josephcrawley on Jan 18, 2023 6:05:53 GMT -8
You're talking about capping the bell not the firebox correct?
If it is the bell I have done it and it worked well. I have also done it with CFB and it did not work well. It was porous enough to allow a seep of smoke to pass through. To correct this I applied a thin layer of sand/clay plaster to the surface.
The vermiculite board I use is called k-fac 19 from thermafiber.
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Post by gadget on Jan 18, 2023 6:07:24 GMT -8
Maybe, there seems to be a few grades of vermiculite around depending on where you live, some are longer lasting than others. Also it appears there is no need to have an insulated roof in a batch box and it also appears that you could have a slightly arched roof thus enabling two bricks to span the roof. If you do try vermiculite you could also try coating it with zircon as this will extend the vermiculite life and possibly help by radiating back some heat. I'm probably going the safe route and use double layered, firebrick ceramic wool and brick. It was something that popped in my head and wanted to ask other people opinions. I've seen your test with zircon and I already have vitcas vermiculate boards and vitcas zircon for the afterburner (going for the vortex core) I have had success with ceramic wool on a roof held up with ceramic buttons and nichrome wire. I got the idea from DIY wool kilns. I made the buttons with a mini DIY kiln from wool scraps and a hand held torch. Works good if you cant get board. |
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Post by martyn on Jan 18, 2023 8:18:12 GMT -8
I have discovered that when coating the vermiculite with zircon it is best to pre heat the vermiculite component first.
To be honest I am still experimenting but I notice that vermiculite will shrink when heated for the first time and if you coat it before it has been ‘shrunk’ then you can get hairline cracks forming in the zircon coating.
So for my last experiment I heated all the ready cut pieces of vermiculite in my kitchen oven for 30 mins at 220c, after they had cooled down, just before I coated the components I misted them with water.
I dont know if this will work much better long term but I dont see any cracks at all so far…….
My original experiments (as in the videos) is still holding up fine apart from a few hairline cracks.
However I am not using the stove every day.
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jonasp
Junior Member
Posts: 102
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Post by jonasp on Jan 19, 2023 1:05:01 GMT -8
You're talking about capping the bell not the firebox correct? If it is the bell I have done it and it worked well. I have also done it with CFB and it did not work well. It was porous enough to allow a seep of smoke to pass through. To correct this I applied a thin layer of sand/clay plaster to the surface. The vermiculite board I use is called k-fac 19 from thermafiber. yes capping of the bell. Good to know it worked well for you! Now I'm back considering that option |
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jonasp
Junior Member
Posts: 102
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Post by jonasp on Jan 19, 2023 1:07:42 GMT -8
I have discovered that when coating the vermiculite with zircon it is best to pre heat the vermiculite component first. To be honest I am still experimenting but I notice that vermiculite will shrink when heated for the first time and if you coat it before it has been ‘shrunk’ then you can get hairline cracks forming in the zircon coating. So for my last experiment I heated all the ready cut pieces of vermiculite in my kitchen oven for 30 mins at 220c, after they had cooled down, just before I coated the components I misted them with water. I dont know if this will work much better long term but I dont see any cracks at all so far……. My original experiments (as in the videos) is still holding up fine apart from a few hairline cracks. However I am not using the stove every day. Thank you for that insight, i might do the same trick if the cut boards will fit my oven.. |
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Post by masonryrocketstove on Jan 23, 2023 16:23:39 GMT -8
The vermiculite board I use is called k-fac 19 from thermafiber. k-fac 19 isn't vermiculite, and behaves a little different than vermiculite does. It's mineral wool fiber made from the recycled waste of metal refining. If the ceramic fiber didn't work but the k-fac did, then it's probably your ceramic fiber board wasn't as dense as your k-fac mineral fiber board. That or maybe the binder used in the fiber board got too hot and burned out, allowing smoke through. |
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Post by josephcrawley on Jan 24, 2023 4:51:00 GMT -8
k-fac 19 isn't vermiculite, and behaves a little different than vermiculite does. It's mineral wool fiber made from the recycled waste of metal refining. If the ceramic fiber didn't work but the k-fac did, then it's probably your ceramic fiber board wasn't as dense as your k-fac mineral fiber board. That or maybe the binder used in the fiber board got too hot and burned out, allowing smoke through. Good to know. It was sold to me as a vermiculite board and I never looked any deeper. It is definitely much denser than the fiber board I used for a roof. |
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