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Post by briank on Feb 23, 2018 6:37:00 GMT -8
Thank you @pigbutton, it was more on the material side of the conversation that I was asking briank and peterberg to comment as their joint comments in another thread asked @karl to build a batch box stove to proove that the geopolymers are up to the job. I am on that quest and wonder what the specifications are, from their point of view, for a material to cope with the rocket environment. Is it so many fires? So many years of use? Such abrasion resistance? Such outside wall of core temp? What else that needs to be shown before it can be recommended for use in an indoor rocket installation? First and foremost, someone needs to actually do one from start to finish and document it. Until then it can’t be recommended to do it yourselfers. Has such been documented yet? Secondly, it needs to stand up to prolonged burn cycles, and without any evidence of actual or impending catastrophic failure, especially the roof of the firebox. Resistance to various temps is pointless until a working model with some evidence of longevity and documentation is achieved. Third, it needs to be shown that this can be done using standardized recipes and techniques that are well documented and illustrated and easily and reliably repeatable without long or expensive periods of experimentation. People are building these and placing them in the middle of their homes. We have already and completely established that commercial refractory materials can be used satisfactorily without endangering the end user, and they’re readily available and relatively affordable. Before recommending their use inside the home, we need some kind of documentation of the use and repeatability of geopolymers in the construction of rocket heaters. There is too much liability involved (both moral and legal) to do otherwise. (In case you’re wondering, every Continuing Medical Education conference I’ve attended every year for the last 25 years has had presentations on liability, and I had to complete separate yearly online liability courses for my malpractice insurance, so it’s something that’s always been in the back of my mind. Doctors have been successfully sued over casual advice they gave to a total stranger at a cocktail party, and I know for a fact that there are liability issues for a forum based on recommendations made there. Forum admin have a moral and legal requirement to air appropriate precautions/warnings regarding something with these levels of danger should catastrophic failure occur.) |
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Post by sksshel on Feb 25, 2018 8:08:16 GMT -8
briank I share your concerns about the various recipes and the level of documentation. It would be helpful if there were 1 or 2 (or few) recipes that are (1) well documented, (2) simple, (3) cheap, made from (4) widely available and (5) consistent components, and (6) completely tested. That is a good part of the reason for this thread. There are many ideas and voices in a forum like this. Some are good, but many will not work. It is really hard to "cut through the smoke" in order to see the issue clearly. There are a few on here that are attempting to do just that. The longest journey begins with a single step. I am unsure about your comments about liability. What you say may very well be true about doctors (I have no basis to question it), but I don't think it applies to some "Joe Shmoe" like me participating and sharing information on a public forum. Most people realize the famous quote by Abraham Lincoln to be true, "You can't believe everything you read on the Internet".  I'm just not sure how the US courts will rule on that. When I get the chance, I will ask a lawyer about it. I could be wrong, but I believe the goal is to build a valid geopolymer from whatever recipe. Geopolymers have a specific chemical makeup, have a long history, and are proven to withstand much worse than the rigors of a BBR/DSR/J-tube. The question that needs to be answered for every recipe is "Does it produce a valid Geopolymer?" The answer to that is somewhat complicated by all of the junk that people want to put into any and all recipes. I believe all 6 requirements listed above have been met by the original posts on this thread. There is one gray area in my mind, is the result a valid uncompromised geopolymer. That is where I think we are.
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Post by drooster on Feb 25, 2018 10:00:25 GMT -8
...Geopolymers have a specific chemical makeup, have a long history, and are proven to withstand much worse than the rigors of a BBR/DSR/J-tube. ... So why have we not seen even a small working J-tube out of low-temperature-setting-geopolymer ? |
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Post by smartliketruck on Feb 25, 2018 16:32:50 GMT -8
So why have we not seen even a small working J-tube out of low-temperature-setting-geopolymer ? Nice "Put up or shut up"! Entirely within the theme of "Answers Questioned" Can you point to a super simple small stand alone proven J tube core that can be quickly thrown together and will work without a bunch of ancillary support systems (chimney, bells and so on), just a burner that will prove a materials worth. Not that I couldn't figure one out for myself, but one that can act as an agreed upon standard test for all comers. This way any new materials can be tested to the same initial standard, I propose we ask " Is it donkey proof?" |
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Post by coastalrocketeer on Feb 25, 2018 16:35:27 GMT -8
...Geopolymers have a specific chemical makeup, have a long history, and are proven to withstand much worse than the rigors of a BBR/DSR/J-tube. ... So why have we not seen even a small working J-tube out of low-temperature-setting-geopolymer ? I think that has a lot to do with it being a VERY broad area of knowledge and research, and the scientific literature mostly concentrating on certain "industrial waste" feedstocks, as well as being rather technically inscrutable to those who are not chemistry whizzes. The information presented by Karl has, I believe, been provided with the intent of spurring people to experiment for themselves, with whatever feedstocks they can obtain locally to be able to create the optimum mixes for various purposes from their available materials. Many of us are not at Karl's level in either chemistry or geology knowledge, and few, if any, have his wide ranging knowledge in both at once. These are rather critical to "instinctively knowing" what feedstocks would work together well for various purposes in creating the desired conditions for polymerization and the desired material properties in the result. There is the complication of chemical and feedstock material terminology in understanding discussions. Multiple trade terms, and field specific names for the same materials in places make discussion and research of feedstock materials difficult. Karl is well convinced that these materials can be ceramic fiber killers in price to performance, and I, for one, very much trust him in that, and want to see these materials made "as easy as cob" in sourcing and mixing/application. For safety and homeowners insurance/permitting reasons, the core I am building as a first attempt, is going outside in an ALL metal and masonry, non-combustible structure, like wood boiler systems. I am relatively poor, so things are going slowly as i can find funds for various materials, or scrounge them, and time to work on it, but I will be updating my own build thread soon. I am not ready to confidently declare that Geopolymers are at a stage where anyone can read a thread here, choose feedstocks, polymerization agents,and additives, make a few test mixes, and build a safe, long lasting core from them, but there are various people working toward that goal (and creating specific repeatable recipes) with various core and mix designs and feedstocks. I can say that all of the tests i've done with the materials i'm experimenting with seem to stand up to a propane plumbers torch quite effectively, and only increase in strength where "fired" My mix does not really qualify as an LTGS, as I am not "wet curing it", and it does not become waterproof before firing. But if it works to make an insulative and moldable ceramic fiber board near equivalent, then that will not matter for my immediate, house warming purposes. I intend to continue to experiment with the feedstock I am now using, and others, to produce Geopolymers for different modes of application, as this incarnation is quite "non-structural", and able to be, due to my chosen design. When I get to experimenting with different mixes and actual definite geopolymerization again, I will make building and testing a standard 4" j-tube core a priority. Might do one more immediately out of my current mix just to replace my propane crab cooker for cooking, and for "firing" dried bricks of my current mix. |
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Post by smartliketruck on Feb 25, 2018 17:20:40 GMT -8
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Post by sksshel on Feb 26, 2018 6:28:49 GMT -8
I've read of at least one geopolymer J-tube rocket stove that has been running for many years.
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Post by sksshel on Feb 26, 2018 7:37:11 GMT -8
The materials required to cast the Batch Box portion of my project will cost under $50.
This does not include the riser or bell. It also doesn't include the materials for the molds. I got most of the mold materials from the waste pile of a new construction house nearby.
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Post by sksshel on Feb 26, 2018 8:07:59 GMT -8
Is 1832 a pretty exact max temp? Cause my understanding is that's about 300 degrees to low for the box or riser. This is very exciting and I hope it works! I'm still researching this. My initial findings are updated to the original post on this thread. |
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Post by coastalrocketeer on Dec 6, 2018 11:25:07 GMT -8
Steve, trying to replicate your mix, and have a few questions...
1) is this citric acid or acetic acid...
vinegar is acetic, citric is vitamin C (usually a powder)
Says: “$2 gallon at big lots”
2) 3 Oz of “citric acid” is only 1% of total formula weight?
3) 4 Oz H2O only one percent of total formula weight?
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Post by sksshel on Dec 6, 2018 11:33:10 GMT -8
Steve, trying to replicate your mix, and have a few questions... 1) is this citric acid or acetic acid... vinegar is acetic, citric is vitamin C (usually a powder) Says: “$2 gallon at big lots” 2) 3 Oz of “citric acid” is only 1% of total formula weight? 3) 4 Oz H2O only one percent of total formula weight? It should be acetic acid (vinegar). Just so you know, I abandoned this formula because it did not pass all of the tests. I instead used this one: donkey32.proboards.com/thread/3283/geopolymer-code-named-kansas-city?page=1&scrollTo=29144 |
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Post by coastalrocketeer on Dec 6, 2018 12:04:15 GMT -8
Thanks Steve! Good to have this link at the end then... pointing anyone to else to the final version of the mix :-)
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Post by permaculturebob on Dec 17, 2019 16:39:35 GMT -8
Hi sksshel, it's been about a year since you put up this thread, what were the results of your castings? Any tips on things to look out for?
I'm planning to do 4 basic molds, half a shoebox at a time, split horizontally, with some sort of overlapping joint where they come together. Any thoughts?
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Post by Deleted on Dec 18, 2019 7:58:30 GMT -8
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Post by sksshel on Dec 18, 2019 8:58:42 GMT -8
Hi sksshel, it's been about a year since you put up this thread, what were the results of your castings? Any tips on things to look out for? I'm planning to do 4 basic molds, half a shoebox at a time, split horizontally, with some sort of overlapping joint where they come together. Any thoughts? One issue to consider with many "castables" is shrinkage. I elected to cast flat pieces, cut them to exact size and put the building blocks together. It's not sexy, but it worked very well. The "exoskeleton" facilitated this method. It also enable the ability to remove the "engine" from the bell and upgrade it to the DSR2. It also allows for ongoing maintenance as required. The links provided by Karl document this concept. |
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I'm just not sure how the US courts will rule on that. When I get the chance, I will ask a lawyer about it. 
