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Post by gadget on Mar 23, 2018 15:05:47 GMT -8
Hey Matt,
I've watched your fiber board video a couple of times. I would love to hear how your burn chamber that does not have fire brick in it is holding up to wood loading. I'm considering a burn box made of fiber board that has rigidizer and a face coat added to it. I have a 3" thick piece of 2300F fiber board that is about the right size of a burn chamber. I'm thinking it may make a good burn chamber floor for setting wood on.
This is a great thread, lets keep it going. I think ceramic fibers are the future for wood burning.
-Gadget
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Post by matthewwalker on Mar 24, 2018 10:16:30 GMT -8
Gadget, it's holding up great by my standards. I'm here nearly through year two with this core in daily hard use and the firebox "cheeks" are slightly hollowed from abrasion, which is to be expected. In my opinion, like the secondary air solutions, they should be expected to be wear areas. Almost all efficient wood heating units have consumable parts of one type or another. There are air delivery tubes, firebrick linings, vermiculite board baffles, catalytic converters, etc. In the case of a CFB firebox, the repair is so simple and affordable that I feel it's one of the better compromises in a heater. When it's time I'll simply either replace those panels, or just stick a utility knife in there and cut out the problem spots and insert some new replaceable cheeks.
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Post by gadget on Mar 25, 2018 21:31:10 GMT -8
Gadget, it's holding up great by my standards. I'm here nearly through year two with this core in daily hard use and the firebox "cheeks" are slightly hollowed from abrasion, which is to be expected. In my opinion, like the secondary air solutions, they should be expected to be wear areas. Almost all efficient wood heating units have consumable parts of one type or another. There are air delivery tubes, firebrick linings, vermiculite board baffles, catalytic converters, etc. In the case of a CFB firebox, the repair is so simple and affordable that I feel it's one of the better compromises in a heater. When it's time I'll simply either replace those panels, or just stick a utility knife in there and cut out the problem spots and insert some new replaceable cheeks. That is great to hear! I would love to see a follow up video if and when you do a spring cleaning on the heater, especially on the firebox. Have you thought of or experimented with any patching yet? Thats to say for large dings or areas with lots of wear. I was thinking some kind of refractory "putty" applied with a putty knife or how about colloidal silica soaked loose fill ceramic fiber for patching?? Thanks again for sharing so much good info!!! You and others out there helping us newbies. -Gadget |
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Post by esbjornaneer on Mar 27, 2018 8:45:29 GMT -8
matthewwalker I would love to hear your comment to @yasintoda 's post: In france we need to insure our stoves for 10 years, just like houses. It changes the way you think, for sure ! And also Yasin's comment about the idea of certain parts needing replacing within the 10 year guarentee time. So what is the longevity we should aim/build for, is it (should it be) different in different countries? Then it will be difficult to have a building material 'recommended' as what is acceptable in a 'throw-away-society' is not acceptable in a more quality restricted country. (I am not commenting on the quality of the core here, nor the ability of a material to insulate, just the length of time it can be used in a location within the stove.)
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Post by gadget on Apr 28, 2018 16:19:12 GMT -8
matthewwalker I would love to hear your comment to @yasintoda 's post: In france we need to insure our stoves for 10 years, just like houses. It changes the way you think, for sure ! And also Yasin's comment about the idea of certain parts needing replacing within the 10 year guarentee time. So what is the longevity we should aim/build for, is it (should it be) different in different countries? Then it will be difficult to have a building material 'recommended' as what is acceptable in a 'throw-away-society' is not acceptable in a more quality restricted country. (I am not commenting on the quality of the core here, nor the ability of a material to insulate, just the length of time it can be used in a location within the stove.) I personally like the idea of long life. I think that can be had with a ceramic fiber board burn chamber if a face coat is added. Just need to figure out a good recipe that is easily repaired that can handle the wood abrasion. I have been working on a face coat and testing it. Best formula I have so far is 1/3 clay (from my subsoil) 1/3 ground up firebrick 1/3 alumina sand blast media(pure white 220mesh) I'm trying to stay with commonly available items. I picked up some cat litter that is bentonite clay from the store yesterday to try and help with some cracking during drying. So far it is looking promising. It may not be idiot proof but it should help allot with the wood abrasion. I think the benefits far out way the longevity issue if there even will be one. Matt will have to keep us up to date since he seems to be the one that is pioneering this concept. Matt how about an update with video? -Gadget |
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kkp
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Post by kkp on May 20, 2018 9:31:27 GMT -8
matthewwalker I would love to hear your comment to @yasintoda 's post: And also Yasin's comment about the idea of certain parts needing replacing within the 10 year guarentee time. So what is the longevity we should aim/build for, is it (should it be) different in different countries? Then it will be difficult to have a building material 'recommended' as what is acceptable in a 'throw-away-society' is not acceptable in a more quality restricted country. (I am not commenting on the quality of the core here, nor the ability of a material to insulate, just the length of time it can be used in a location within the stove.) I personally like the idea of long life. I think that can be had with a ceramic fiber board burn chamber if a face coat is added. Just need to figure out a good recipe that is easily repaired that can handle the wood abrasion. I have been working on a face coat and testing it. Best formula I have so far is 1/3 clay (from my subsoil) 1/3 ground up firebrick 1/3 alumina sand blast media(pure white 220mesh) I'm trying to stay with commonly available items. I picked up some cat litter that is bentonite clay from the store yesterday to try and help with some cracking during drying. So far it is looking promising. It may not be idiot proof but it should help allot with the wood abrasion. I think the benefits far out way the longevity issue if there even will be one. Matt will have to keep us up to date since he seems to be the one that is pioneering this concept. Matt how about an update with video? -Gadget
That alumina sand is pretty expensive. Is that the only type of sand that is acceptable?
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Post by gadget on May 20, 2018 10:15:30 GMT -8
I personally like the idea of long life. I think that can be had with a ceramic fiber board burn chamber if a face coat is added. Just need to figure out a good recipe that is easily repaired that can handle the wood abrasion. I have been working on a face coat and testing it. Best formula I have so far is 1/3 clay (from my subsoil) 1/3 ground up firebrick 1/3 alumina sand blast media(pure white 220mesh) I'm trying to stay with commonly available items. I picked up some cat litter that is bentonite clay from the store yesterday to try and help with some cracking during drying. So far it is looking promising. It may not be idiot proof but it should help allot with the wood abrasion. I think the benefits far out way the longevity issue if there even will be one. Matt will have to keep us up to date since he seems to be the one that is pioneering this concept. Matt how about an update with video? -Gadget
That alumina sand is pretty expensive. Is that the only type of sand that is acceptable?
I picked up a 50lbs bag from a sand blast company for $40. It was much smaller in volume than the same 50lbs bag of say sand. It is very heavy and dense. If its just for a face coat then you shouldn't need to much. I guess it is not much cheaper then castable refractory or a commercial furnace lining so maybe it isn't worth it  ? I try to avoid quartz sand because it has allot of expansion at different temperatures. Pure silica sand is suppose to be better. I tired a ratio of 25% clay and 75% alumina and heated it with a torch just on one face. It seemed to be stronger than with the firebrick. Goal is to simulate the heating it would get in a burn box and have it be strong enough for wood loading. Interesting side note, I made some flat disk with this 25/75 mix and heated them up. It made for a really nice flat sanding block at 220 grit. Sanded steel really well. If you get it to hot with the torch the alumina melts and makes it smooth, other wise the surface feels like 220 sand paper. On a side note, I have been saving spark plugs from work for a while now and I smash them up for the alumina ceramic grog. It is a very high mullite ceramic and very strong stuff. I'm going to try and find some mullite grog near me. That stuff is amazing. -Gadget |
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kkp
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Post by kkp on May 20, 2018 10:22:59 GMT -8
What about Diatomaceous Earth? Does it have refractory qualities?
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Post by gadget on May 20, 2018 11:36:18 GMT -8
What about Diatomaceous Earth? Does it have refractory qualities?
Yes it is a refractory. It also has some insulating properties due to the shape of the diatoms. I forgot all about it as a cheap common source of material. I am going to pick some up this week and do some experiments. On a side note, I picked up some clay kitty litter for a bentonite source. It appears to have been fired because the material is not soluble in water. Anyone know if there is a brand of kitty litter that still uses the unfired clay? bentonite adds lots of plasticity and can help with low clay ratio mixes. -gadget |
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kkp
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Post by kkp on May 22, 2018 16:57:46 GMT -8
Actually what I want the sand for is for mortar in my bell. But thinking more on it, the bell isn't going to get real hot. Sure there will be an area at the top that gets hot and I will mortar accordingly. Below that area I don't expect the bricks to get very warm so I'm pretty sure some plain ole cheapy play sand will do fine mixed with a fireclay binder. If my bell ever gets hot enough to melt that mix I'd expect the bricks to melt shortly thereafter. I was also thinking I may paint the interior of the bell with waterglass to act as a sort of sealant
Edit: Got the pipe. I'm gtg now except for rigidizer and I'll buy that this weekend.
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Post by etownandrew on Nov 16, 2018 16:15:22 GMT -8
It appears that there are two types of binders (organic and non-organic) that are used to build CFBs. I appear to have gotten the organic type and the sharp smoke generated when being initially heated is really strong. I think that I am going to need to pull off my CFB tops from my rocket mass heater and heat them to 615F in an outdoor area to burn off the stinky binders. The boards will likely be discolored brown by that. I got this from the following instruction link that seems to match my experience. www.sunshineglass.com/pdf/using-fiber-board.pdf |
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Post by gadget on Dec 11, 2018 23:42:58 GMT -8
It appears that there are two types of binders (organic and non-organic) that are used to build CFBs. I appear to have gotten the organic type and the sharp smoke generated when being initially heated is really strong. I think that I am going to need to pull off my CFB tops from my rocket mass heater and heat them to 615F in an outdoor area to burn off the stinky binders. The boards will likely be discolored brown by that. I got this from the following instruction link that seems to match my experience. www.sunshineglass.com/pdf/using-fiber-board.pdfetownandrew, I picked up a 3" thick slab CFB for the base of my burn chamber. I was initially disappointed due to the fact that it was a kind off white/yellow color and appeared to have been clued to a surface due to the yellowish substance. I took a torch to it and it started to smoke and stink. After some burning the smoke went away and it started to act like normal CFB. The area I burned to a black soot then was gone. Left behind is a nice white CFB. The coating appears to be mostly on the outside surface of the board, I'm wondering if it is just coated to help it survive shipping and installation. Try just taking a torch to a small piece and see if it is just on the outside of the board. |
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Post by etownandrew on Dec 12, 2018 13:37:14 GMT -8
It appears that there are two types of binders (organic and non-organic) that are used to build CFBs. I appear to have gotten the organic type and the sharp smoke generated when being initially heated is really strong. I think that I am going to need to pull off my CFB tops from my rocket mass heater and heat them to 615F in an outdoor area to burn off the stinky binders. The boards will likely be discolored brown by that. I got this from the following instruction link that seems to match my experience. www.sunshineglass.com/pdf/using-fiber-board. The coating appears to be mostly on the outside surface of the board, I'm wondering if it is just coated to help it survive shipping and installation. Try just taking a torch to a small piece and see if it is just on the outside of the board. That sounds possible. Certainly would be easier than what I did. |
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Post by johnjorgensen on Jan 26, 2019 10:28:13 GMT -8
Insulation in the firebox is always better than mass in my opinion. High mass anywhere near the burn robs heat from combustion, and if it gives any back in a useable way, it's far less than it stole from the early burn, IMO. Get the mass out of the fireboxes for peak performance, balance it with your durability goals. Regarding a batch box - does your statement stand true even if the brick/mass is highly insulated? For instance, a brick firebox wrapped with 3-inches of Rockwool? I tried to make a sort of insulated mirror as the roof/top lid of my batch box. Havent really fired it up yet. Ill try to post a link to it if you like... |
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? I try to avoid quartz sand because it has allot of expansion at different temperatures. Pure silica sand is suppose to be better.
