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Post by masonryrocketstove on Mar 22, 2023 22:11:13 GMT -8
As to why the afterburner pieces don't crack.. this is just speculation, but: the afterburner area gets hotter than the firebox.. hot enough that the vermiculite probably vitrifies from clay to fully-fired ceramic. If that's the case, the vermiculite board in the afterburner isn't clay anymore, and doesn't undergo the moisture expansion and shrinkage that vermiculite boards in the firebox do.
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Post by martyn on Mar 22, 2023 23:22:05 GMT -8
Yes that is right when the board is super heated it becomes quite different, very brittle rather than absorbent.
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Post by Vortex on Mar 23, 2023 2:43:47 GMT -8
Vortex, --I'm guessing that uneven heating is causing the vertical cracks, since the lower part is shielded from sudden startup heat by the V-shaped pieces. Top part heats faster than the part behind the V sections, expanding til it cracks to relieve stress. Just a thought, for those still designing, it's probably best to avoid temp differences across larger pieces. I considered that, but thought if that was the case it would have cracked horizontally along where it goes behind the V floor pieces, but maybe you're right. As to why the afterburner pieces don't crack.. this is just speculation, but: the afterburner area gets hotter than the firebox.. hot enough that the vermiculite probably vitrifies from clay to fully-fired ceramic. If that's the case, the vermiculite board in the afterburner isn't clay anymore, and doesn't undergo the moisture expansion and shrinkage that vermiculite boards in the firebox do. That makes sense, pieces from the afterburner ring like a fired ceramic. |
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jonasp
Junior Member
Posts: 102
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Post by jonasp on Mar 23, 2023 22:45:33 GMT -8
Interesting information thanks for sharing everyone.
I'll keep the vermiculite boards unfixed but supported by some extra smaller pieces fixed on 1 side. (Pictures come later)
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jonasp
Junior Member
Posts: 102
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Post by jonasp on Mar 26, 2023 23:14:55 GMT -8
update all the boards are unfixed besides the supports on the sides which are fixed only on the bottom. Made the white oven which rests on the vermiculite boards, did some insulation around the oven to have more heat inside the oven (really curious what the temps will be) Welded the frame of the doors     |
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jonasp
Junior Member
Posts: 102
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Post by jonasp on Apr 17, 2023 3:51:57 GMT -8
The doors are made, the roof is closed, the first fire is lit! I had a nice vortex forming with the test burn. Still need to do some additional finishes. (loam, finishing up some nice touches inside the firebox, oven and afterburner, finishing the door handles, etc etc) Oven door is still open but already hitting high temperatures, really wondering what temps it'll reach once it's insulated.     |
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Post by Dan (Upstate NY, USA) on Apr 17, 2023 17:35:43 GMT -8
Nice absolute "stove porn". Not sure how that will translate outside the English language, my apologies!
And that looks like Bosch tool in the background.
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Post by martyn on Apr 17, 2023 21:41:04 GMT -8
Very neat build, well done.
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jonasp
Junior Member
Posts: 102
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Post by jonasp on Apr 18, 2023 0:07:56 GMT -8
Nice absolute "stove porn". Not sure how that will translate outside the English language, my apologies! And that looks like Bosch tool in the background. haha i love reading other threads and all the knowledge everyone is sharing, giving some (stove) porn back is the least i can do  That is a bosch drill serving me very well. |
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jonasp
Junior Member
Posts: 102
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Post by jonasp on Apr 18, 2023 0:09:33 GMT -8
Very neat build, well done. Thank you! So many skills I've learned(by far not mastered..) during the making of the stove I hope to see some numbers of the white oven soon |
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jonasp
Junior Member
Posts: 102
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Post by jonasp on Apr 23, 2023 22:49:50 GMT -8
Today second full burn. I do have some white smoke coming out, would this purely be the wood? (It should be dry, mix of pine and bit of hard wood) The afterburner windows get's clear and black depending how hot it is.. Sometimes the vortex wants to creep forward but mostly stays in place (can i finetune this to stay more in place?) Here's a bad video, part of the vortex is barely visible.. drive.google.com/file/d/1GkMp40wJSguA0CQBz-4dpZkhXLMGgM7m/view?usp=share_linkI've placed a thermometer on the oven floor and it already get's 230 degrees without oven door |
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Post by Vortex on Apr 24, 2023 1:28:50 GMT -8
Hi jonasp, It's hard to see clearly with that much smoke deposit on the windows, that is a sure sign it's been overfueling though and explains the white smoke. It can take a while to get used to the stove and how best to run it, it will teach you through watching it.
The vortex will creep forward in the afterburner if you reduce the primary air or if the amount of wood gas being produced increases for some reason. Stack the wood front to back with the largest pieces at the bottom gradually getting smaller towards the top, avoiding big gaps. Don't use too much kindling, slow startups are much better than fast ones, the afterburner glass will stay clear when you're doing it right. Start with 20% csa primary, with the bottom air completely shut off, if this is leaking it can cause it to overfuel, after the fire has peaked open the bottom air a small bit. Let me know how you get on.
Trev
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jonasp
Junior Member
Posts: 102
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Post by jonasp on Apr 24, 2023 3:12:43 GMT -8
Hi jonasp, It's hard to see clearly with that much smoke deposit on the windows, that is a sure sign it's been overfueling though and explains the white smoke. It can take a while to get used to the stove and how best to run it, it will teach you through watching it. The vortex will creep forward in the afterburner if you reduce the primary air or if the amount of wood gas being produced increases for some reason. Stack the wood front to back with the largest pieces at the bottom gradually getting smaller towards the top, avoiding big gaps. Don't use too much kindling, slow startups are much better than fast ones, the afterburner glass will stay clear when you're doing it right. Start with 20% csa primary, with the bottom air completely shut off, if this is leaking it can cause it to overfuel, after the fire has peaked open the bottom air a small bit. Let me know how you get on. Trev Thanks for the information! I definitely made the starts too fast then. I'll tweak it next time and see how the vortex reacts |
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Post by martyn on Apr 24, 2023 5:50:36 GMT -8
I would say you need a good dozen fires before the whole system is getting dry and it wont run consistently or at its full potential until all the refractory is dry.
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jonasp
Junior Member
Posts: 102
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Post by jonasp on Apr 24, 2023 22:07:44 GMT -8
ok let's see how it progresses. Today i started with a slower start up and lit the fire more at front top. Eventually it did overfuel again at 20% intake.  maybe even less small wood at the top? Or should i start without the bypass so it'll go even slower? Once it overfuels and then slows back down into a nice vortex i still get the white smoke any reason for this? |
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