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Post by matthewwalker on Jan 1, 2018 7:23:02 GMT -8
I've been biting my tongue, but I no longer can. You are going to have a hard time getting away from crystalline silicate when building a stove. I would much rather deal with a solid board that barely dusts unless you cut it than a bag full of powder, but you guys do you. www.absorbentproductsltd.com/diatomaceous-earth-vs-zeolite.html |
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Post by Deleted on Jan 1, 2018 8:12:24 GMT -8
Only free silica like Diatomaceous Earth polymerizes in the lungs.
High quality clays with high alumino content contain virtually no free silica.
One can use grogs which do not contain free silica.
Use of respiratory protection is recomended for handling any kind of dust even wood dust or wheat flour.
Of course one can also use wet clays, but needs to measure the water content to be able to calculate the propper amounts of incredients.
Though shipping is significantly higher.
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Post by pigbuttons on Jan 1, 2018 8:26:07 GMT -8
Here is a proven recipe that I came up with over the summer. It has only been used to make samples, but those samples have been placed in the burn chamber of my J-tube and have proven durable. There are an infinite number of combinations that will work based on the vast number of ingredients and the ratios that can be tried. After doing many many batches, and monitoring which products yielded what characteristics, these products and ratios produced an excellent result. It may seem overly complex, and it is all store bought because I want it to be repeatable in the future and home dug clay will vary too much to my taste. The clay products were purchased from theceramicshop.com, the KOH from some ebay vendor, and the concrete aggregate vermiculite (agricultural vermiculite will most definitely not work), from a local construction materials supply house. The vermiculite is added to reduce weight as its volume is quite high per gram when compared to the clays.
H20 120g
KOH 25g
Kaolin 40g
Glomax 40g
Petalite 15g
Wollastonite 15g
vermiculite 30g
The H20 and KOH are mixed until completely in solution ( time will vary with heat, but can be done at room temp with patience).
The dry ingredients are all mixed thoroughly together.
Using a plastic paddle mixer in a drill at low speed, the liquid is slowly added to the dry ingredients until fully blended. It should yield a thick paste about like peanut butter (hope no one is allergic:joking).
Press into a mold. I use my shop press, and a small amount of liquid is likely to come out, but only a couple of table spoons if all is well.
It is allowed to air dry until it feels hard to the touch. For this size it took two days.
It is then put into the kitchen oven at the lowest setting (+- 250F) for four hours.
After allowing it to cool it was again put in the oven at 450F for four hours.
At this point it is relatively stable, you can get it wet and it sheds water. But one sample was left in this condition and after several months in our humid Alabama weather it had some efflorescence, the next step will fix that.
I put the other sample into my J-tube at the floor of the riser and ran a one hour fire. Multiple firings have not produced cracking or damage of any kind.
In lieu of firing in the stove I found that curing the surface with a map gas torch until the surface shines red will also stop any efflorescence.
I hope this will help those wishing to try geopolymers. In stead of heating in the oven, short, low temp firings of the stove itself should produce the same results. What I was trying to do is drive off any unreacted water from the material as slowly as practical because any of it turning to steam in any quantity inside the sample will make it pop and usually crack.
...
These ratios were approximately what were in one of the samples of Davidovitz's patent.
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Post by matthewwalker on Jan 1, 2018 8:33:27 GMT -8
Use of respiratory protection is recomended for handling any kind of dust even wood dust or wheat flour. This is exactly my point. Wear masks when handling dust. Also, zeolite contains free silica, but typically it's below the notification point which just means they don't have to report it. It's there, so wear masks when handling any of these things, please. Refractory mixes are more than just clays, there will be free silica in almost all of our materials. Cutting fire brick? Free silica. Please folks, this isn't a competition, let's all be safe. |
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Post by Deleted on Jan 1, 2018 8:35:50 GMT -8
Use wet clays, and measure the water content to be able to calculate the propper amounts of incredients.
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Post by briank on Jan 1, 2018 8:52:35 GMT -8
Here is a proven recipe that I came up with over the summer. It has only been used to make samples, but those samples have been placed in the burn chamber of my J-tube and have proven durable. There are an infinite number of combinations that will work based on the vast number of ingredients and the ratios that can be tried. After doing many many batches, and monitoring which products yielded what characteristics, these products and ratios produced an excellent result. It may seem overly complex, and it is all store bought because I want it to be repeatable in the future and home dug clay will vary too much to my taste. The clay products were purchased from theceramicshop.com, the KOH from some ebay vendor, and the concrete aggregate vermiculite (agricultural vermiculite will most definitely not work), from a local construction materials supply house. The vermiculite is added to reduce weight as its volume is quite high per gram when compared to the clays. H20 120g KOH 25g Kaolin 40g Glomax 40g Petalite 15g Wollastonite 15g vermiculite 30g The H20 and KOH are mixed until completely in solution ( time will vary with heat, but can be done at room temp with patience). The dry ingredients are all mixed thoroughly together. Using a plastic paddle mixer in a drill at low speed, the liquid is slowly added to the dry ingredients until fully blended. It should yield a thick paste about like peanut butter (hope no one is allergic:joking). Press into a mold. I use my shop press, and a small amount of liquid is likely to come out, but only a couple of table spoons if all is well. It is allowed to air dry until it feels hard to the touch. For this size it took two days. It is then put into the kitchen oven at the lowest setting (+- 250F) for four hours. After allowing it to cool it was again put in the oven at 450F for four hours. At this point it is relatively stable, you can get it wet and it sheds water. But one sample was left in this condition and after several months in our humid Alabama weather it had some efflorescence, the next step will fix that. I put the other sample into my J-tube at the floor of the riser and ran a one hour fire. Multiple firings have not produced cracking or damage of any kind. In lieu of firing in the stove I found that curing the surface with a map gas torch until the surface shines red will also stop any efflorescence. I hope this will help those wishing to try geopolymers. In stead of heating in the oven, short, low temp firings of the stove itself should produce the same results. What I was trying to do is drive off any unreacted water from the material as slowly as practical because any of it turning to steam in any quantity inside the sample will make it pop and usually crack. ... These ratios were approximately what were in one of the samples of Davidovitz's patent. Excellent, thank you! This is a recipe describing exact amounts and techniques that can be easily followed (and its no longer just "on the horizon" ;-). It deserves its own, new thread. Possible sources for these materials Could/should be mentioned. Someone needs to try this for a full batch box build ASAP. (Sorry, I have my hands full with other stuff right now.) |
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Post by pigbuttons on Jan 1, 2018 9:28:34 GMT -8
Just an FYI, the samples above are only about 4 cubic inches. It will take some techniques and a fair amount of expense to get a full sized stove core. I'm sure it will be no more expensive than the fiber board, fire brick, and refractory cement. The biggest advantage I see is that when it is done, it is essentially made out of stone, no abrasion issues, should never burn out, and is not dependent on the materials as far as shape is concerned. I'd love to be able to further my experiments but unfortunately I have a house to finish. The wife has been patient for the last 15 years, but it is time to press on to the final goal. Off topic but here is a thread with some pics: permies thread. |
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Post by briank on Jan 1, 2018 11:51:37 GMT -8
Just an FYI, the samples above are only about 4 cubic inches. It will take some techniques and a fair amount of expense to get a full sized stove core. Ok, thanks for being honest. I think some folks are under the false impression that this method is 1) ready for real world application and 2) would be cheaper than purchasing existing commercially available refractory products. |
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Post by patamos on Jan 3, 2018 20:51:16 GMT -8
I've been biting my tongue, but I no longer can. You are going to have a hard time getting away from crystalline silicate when building a stove. I would much rather deal with a solid board that barely dusts unless you cut it than a bag full of powder, but you guys do you. www.absorbentproductsltd.com/diatomaceous-earth-vs-zeolite.htmlYa, pre-made, when available and cost effective is a good way to go. The main application i can see for casting LGTS is unusually shaped components. Like casting around a bypass damper flue. I wonder how effectively a LGTS shaped tube could replace the vertical section of the secondary air delivery in a BBR? If it could handle the knocks and not need replacement every few years then such systems would become more viable for the average Joe (many of whom will keep running a heater after a metal air feed tube has burned out...) |
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Post by Deleted on Jan 4, 2018 7:03:24 GMT -8
If it could handle the knocks and not need replacement every few years then such systems would become more viable for the average Joe The strength of cementitious systems or resinous systems lies in their great diversity, which makes it possible to adapt the properties of the compound to the requirements. LTGS can be virtually all one may ever want. Even highly thermally conductive for a air feed tube, which will never burn out. |
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Post by fzurzolo on Jan 4, 2018 9:27:25 GMT -8
Here is a proven recipe that I came up with over the summer. It has only been used to make samples, but those samples have been placed in the burn chamber of my J-tube and have proven durable. There are an infinite number of combinations that will work based on the vast number of ingredients and the ratios that can be tried. After doing many many batches, and monitoring which products yielded what characteristics, these products and ratios produced an excellent result. It may seem overly complex, and it is all store bought because I want it to be repeatable in the future and home dug clay will vary too much to my taste. The clay products were purchased from theceramicshop.com, the KOH from some ebay vendor, and the concrete aggregate vermiculite (agricultural vermiculite will most definitely not work), from a local construction materials supply house. The vermiculite is added to reduce weight as its volume is quite high per gram when compared to the clays. H20 120g KOH 25g Kaolin 40g Glomax 40g Petalite 15g Wollastonite 15g vermiculite 30g The H20 and KOH are mixed until completely in solution ( time will vary with heat, but can be done at room temp with patience). The dry ingredients are all mixed thoroughly together. Using a plastic paddle mixer in a drill at low speed, the liquid is slowly added to the dry ingredients until fully blended. It should yield a thick paste about like peanut butter (hope no one is allergic:joking). Press into a mold. I use my shop press, and a small amount of liquid is likely to come out, but only a couple of table spoons if all is well. It is allowed to air dry until it feels hard to the touch. For this size it took two days. It is then put into the kitchen oven at the lowest setting (+- 250F) for four hours. After allowing it to cool it was again put in the oven at 450F for four hours. At this point it is relatively stable, you can get it wet and it sheds water. But one sample was left in this condition and after several months in our humid Alabama weather it had some efflorescence, the next step will fix that. I put the other sample into my J-tube at the floor of the riser and ran a one hour fire. Multiple firings have not produced cracking or damage of any kind. In lieu of firing in the stove I found that curing the surface with a map gas torch until the surface shines red will also stop any efflorescence. I hope this will help those wishing to try geopolymers. In stead of heating in the oven, short, low temp firings of the stove itself should produce the same results. What I was trying to do is drive off any unreacted water from the material as slowly as practical because any of it turning to steam in any quantity inside the sample will make it pop and usually crack. ... These ratios were approximately what were in one of the samples of Davidovitz's patent. This is great! I have a few questions though, about the formulation. Why so many different clays/minerals? Are you trying to hit a certain balance of minerals? If so, what would that be? And then, how realistic would it be to use regular clay from the ground if the formulation needs to be so precise?
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Post by coastalrocketeer on Jan 4, 2018 10:55:53 GMT -8
This is great! I have a few questions though, about the formulation. Why so many different clays/minerals? Are you trying to hit a certain balance of minerals? If so, what would that be? And then, how realistic would it be to use regular clay from the ground if the formulation needs to be so precise?
Using your own local clay is very possible, but requires a bit of experimenting to find out for sure if it will work well, and what the best ratios to other ingredients are. |
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Post by coastalrocketeer on Jan 4, 2018 12:34:47 GMT -8
This is great! I have a few questions though, about the formulation. Why so many different clays/minerals? Are you trying to hit a certain balance of minerals? If so, what would that be? And then, how realistic would it be to use regular clay from the ground if the formulation needs to be so precise?
Using your own local clay is very possible, but requires a bit of experimenting to find out for sure if it will work well, and what the best ratios to other ingredients are. And there are a TON of possibilities... As far as ingedients, and ways to "activate" the binder... Acids or caustics, etc... I think this extremely broad range of possibilities, and the confusion of trying to keep straight, info from the multiple discussions therof, are a big part of what keeps many of us from confidently trying this. I'm experimenting in my own thread with Zeolite, as both binder and aggregate, as this was the first thing I found available locally that didn't require a bunch of stuff I'd have to travel hours to obtain. Per Karl's advice in my own thread, I am going to be branching out to trying the zeolite binder with my local clay soil as aggregate, as soon as I find some clay deposits around here that I can dig, and be confident that I'll be able to get plenty more of the same in the future. |
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Post by pigbuttons on Jan 4, 2018 21:36:38 GMT -8
This is great! I have a few questions though, about the formulation. Why so many different clays/minerals? Are you trying to hit a certain balance of minerals? If so, what would that be? And then, how realistic would it be to use regular clay from the ground if the formulation needs to be so precise?
Your reasoning is exactly right fz'. I made a number of experiments with each of the listed ingredients and many more besides. Those chosen were of the group that actually reacted with the KOH that I was using. After testing the samples of each individual ingredient over a couple of weeks some performed better than others in areas such as water resistance, shrinkage, not cracking at high temp, thermal shock, abrasion resistance, etc. So I started combining the best performers to see if I could get something that would be suitable for my purposes. This formula is what I came up with. There were some clays that worked 'well enough' by themselves, like the kaolin and glomax. But some of the others were slightly better at one particular thing and were therefore included in the final formula. I am very sure that this is by no means "The Best", and certainly not "The Only" combination that would meet my needs, but at some point "good enough" has to be accepted or one will experiment forever. Right now I'm too busy to continue on with my project; hopefully next year I will be free to continue to "MAKE" stuff. Digging local clays is certainly possible but a lot depends on what you intend to do with it. If it is a personal project and you can tolerate some variation in the outcomes that is different from wanting to do something commercially where consistency is more important. Even with these commercially purchased clays the vendor warns of minor variations from lot # to lot # even from the same producer. It comes from the fact that clays are laid down in nature over centuries of erosion and the deposits reflect that variation, usually in the amount of trace elements which can affect the finished product. |
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Post by Deleted on Jan 5, 2018 7:36:21 GMT -8
And then, how realistic would it be to use regular clay from the ground if the formulation needs to be so precise? I have sucessfully geopolymerized Loess Loam, with only 20% or less clay content, by using a zeolite based LTGS binder. One could make a binder from the Loess Loam itself as well, but curing would then require higher temperatures. Loess Loam is about the worst possible clayed soil imaginable. |
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