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Post by coastalrocketeer on Dec 16, 2017 1:01:05 GMT -8
So I took the very first successful (actually hardened, and not too soon) puck I made with Karl's info on Clinoptilolite Zeolite in his long ago post I missed about zeolite geopolymers, which I recently found when searching info on it based in his recent post about his own build using Geopolymerization of this mineral. donkey32.proboards.com/thread/2021I had a couple of bad first tries... One that didn't harden at all, and one that went off so fast in the pot, it was lost entirely, and a bit of a mess to clean up... The third attempt was a little closer to his recommendations, and hardened nicely in the oven overnight at 170F. I put it in a sealed plastic ziplock bag inside it's silicone mold to keep the moisture in and let it stay in the oven overnight, then checked it and found it to be hard enough to unbag and de-mold, so I placed it in the oven at 170 without the bag to bake moisture out... Turned it up to 250 after a couple of hours when it seemed fairly dry, and then up to 350 for 45 minutes or so just to make sure it was totally dry. I wasn't quite right on the binder or the mixing steps per Karl's reccomendations, but it still hardened into something about like plaster of Paris. Refractory ability agains the propane blow torch seems to be excellent, and actually glassifies, and improves strength of the material's surface where it melts and bubbles at the center of the torch's blast of heat... I used significantly more toilet paper, about 6 sheets of Scott single ply in a finished puck that weighed 140grams after drying. This led to structural issues, and I believe it would have been less prone to cracking had I used something closer to one sheet or his reccommendations of a couple of sheets per dry kilo geopolymer refractory mass. I will post some photos and a video up to YouTube as soon as I figure out a good image hosting site... |
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Post by coastalrocketeer on Dec 16, 2017 1:29:06 GMT -8
The cracking may have also been due to having let it set in the oven for a period (first hour) before squeezing it into a slightly undersized bag in it's soft silicone mold. The cracks seem to be where I flexed it getting it into the bag after it was already part way cured.
I am going to do an "immediate needs" core from a mix similar to this one after one more round of testing with some additional advice on mixing methodology from Karl, and combine that with Pinhead's ceramic fiber lined stove pipe as a riser.
Just got two 50 gallon barrels and going to get one more for initial barrel and two more heat radiating bells...
Recently aquired a 48"x25 foot roll of 8lb 2300F ceramic fiber blanket, so I'm Rollin' in the stuff! (If anyone in Oregon, or visiting my area wants to buy some, I'll sell some of it by the square foot. My purchase cost was $2/sq foot.
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Post by coastalrocketeer on Dec 22, 2017 22:33:34 GMT -8
Photos - Unbroken portion of "heart" shaped puck, oven cured at 170F, with the broken off piece I'd first torch-tested and surface sintered/glassified, with a small butane torch, sitting on top  Closer views of the "flame treated" piece    Closer views of Some smaller broken off pieces, and the first flame sintered piece     side view is of largest piece of puck broken at weak area showing internal cross section... After 20-30 minutes of flame treatment with a plumbers torch, Melting never went deeper than 3/16", and absolutely no spalling, Explosive or otherwise, occurred.       The last two are close ups of the remains of the first torch-flame treated broken off scrap that was placed in the hot coal bed of an insulative refractory lined box stove... Expanded up like glassy volcanic lava... I believe the lining board is called skamol, very expensive, and not likely as insulative or heat resistant as an optimized geopolymer mix, which this first semi-successful experiment definitely is NOT... It is however highly encouraging that based on Karls advice about process/methods, and the reasoning behind them, I will be able to make a very successful refractory, and with further experimentation and some well chosen aggregates and fibers, a strong and highly insulative one. |
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Post by coastalrocketeer on Dec 22, 2017 23:31:23 GMT -8
Video (at 2x speed, because I'm too boring for normal speed viewing, and I like sounding like a chipmunk)
So the time for this (horribly badly mixed and portioned) geopolymer puck to reach 140 degrees or more where it was too hot for me to keep my finger tips on the opposite side was 2 minutes in real time...
Unfortunately it does not stand up to hearth temps for an hour with heat from all sides.
I am, however, confident that with a few small batches and some additional ingredients (mineral wool/rock-wool fibers for crack prevention, and fine granulated blast slag for aggregate/grog) it will become the type of material needed.
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Post by coastalrocketeer on Dec 22, 2017 23:50:37 GMT -8
One thing I will comment about my horrible first try at following Karl's initial guidance is that it seems to turn a LOT of the torch heat hitting it into radiant heat reflected back... Such that I could feel it VERY noticeably on the radiated upon surfaces of my fingers wrapped around the torch handle, and it was a significant part of what made me move my tumb from the bottom of the front face to the side after a short period.
Would describe it as not heavy compared to a similar volume of rock, It also seemed to cool enough to be handle-able quite quickly for something with it's not excessive but not negligible mass...
I would assume those are desirable qualities... But will be trying more mixes and continuing to document the results, as well as now the process and specific materials and amounts, closer to the materials, ratios and methods Karl has since elucidated on further in other threads in response to my, and other's, questions.
Though the expansion of the one piece left in the in the brightly glowing coal bed of the box stove leads me to believe this is not a suitable mix for a rocket stove core as it is. Additionally, I don't know exactly how much water I added or remember exact ratios of lye, binder zeolite, and aggregate zeolite added after initial gelling, as it was the third attempt after two initial failures... End of a long night when I took the silicone mold out of a double boiler pan and slid it into a ziplock bag and placed in the oven on a "disposable grade" steel cookie pan...
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Post by coastalrocketeer on Dec 23, 2017 0:18:44 GMT -8
Time compressed (2x speed) video of my first 7 minutes of applying the propane plumber's torch to one side of the larger puck and using the "Ok, that's getting uncomfortable now!" method of reverse side heat testing... youtu.be/XXSfkNipErI |
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Post by coastalrocketeer on Dec 23, 2017 0:29:53 GMT -8
Took about 2 minutes for the 1-1/2" sample to get too hot for my fingers on the back, which takes 1 minute at 2x speed.
Smoking was most likely burning out of cellulose as I used about 100x more bath tissue than Karl reccommended to prevent cracking during drying.
Stopped entirely once I'd gone over both sides and edges with the torch for about 20 minutes...
I could see doing this to the outsides of a core or plate with a torch to "glassify" and harden the outer shell and make the majority of smoke go inward, during burn-out of an inner wood, or other combustible form material... preferably biomass sourced, wood/cardboard/paper...
My first inner core will be from OSB... So I'll be temporarily extending the riser to 6-1/2' or so with an additional 4' section of ceramic wool connected to the top of my 2-1/2 to 2-3/4 foot tall riser, while burning out the inner form section, in hopes of burning as completely as possible any byproducts of the glue in the OSB.
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Post by Orange on Dec 23, 2017 4:41:30 GMT -8
interesting, so this thing is like ceramic fiber boards (thermal conductivity around 0,1 W/mK)
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Post by pigbuttons on Dec 23, 2017 5:22:00 GMT -8
Interesting stuff. Thanks.
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Post by Deleted on Dec 23, 2017 7:52:34 GMT -8
Thanks for sharing your experiment.
Judging from the pictures the Sweet PDZ powder is rather granular, not a true powder.
The melting indicates a quite high amount of lye.
However natural materials are never pure and even very pure minerals may vary in chemical composition.
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Post by esbjornaneer on Dec 23, 2017 7:59:35 GMT -8
Orange it all depends on what the tepms are too. I can not find any data for geopolymers (there is a scientific article about it but all I see is a mention of 40-100degC not the temps we are interested in). The data I found for cfb it is 0.08 at 600C, but 0.2 at 1000C so a range there too.
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Post by coastalrocketeer on Dec 23, 2017 12:10:22 GMT -8
Thanks for sharing your experiment. Judging from the pictures the Sweet PDZ powder is rather granular, not a true powder. The melting indicates a quite high amount of lye. However natural materials are never pure and even very pure minerals may vary in chemical composition. Yes... I definitely had more lye in that batch than the amounts you reccommended in your posts. I believe that they actually remove any truly micronized portions as this product is intended to be "sprinkled" on the floor of a horse stall, and they want to minimize user's inhalation exposure. The next "test puck" batch I'm doing I have separated the larger granules from the finer stuff with a fairly fine mesh screen (scrap of an old "sheer" window curtain... Wound up with a ratio of 100 grams of finer stuff that passed through the screen, and 83.3333333 grams of coarser stuff that didn't pass through the screen. Will be using a portion of the finer part as the binder. Tried using a pestel and mortar to try making some of the binder material finer but it seemed like it was going to take forever to have any effect in reducing particle size. |
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Post by coastalrocketeer on Dec 23, 2017 12:11:43 GMT -8
I am hopeful that I can come up with a method/recipe for people to use the SweetPDZ product as is, and not have to ball mill a portion of it to use it as binder.
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Post by coastalrocketeer on Dec 23, 2017 12:32:51 GMT -8
Some pics of the fine mesh and the two different fractions it produced The mesh:  The finer portion (100 grams)  The coarser portion (83-1/3 grams)   Though the finer portion still has small grains in it, it does seem to have a fraction that is very fine powder... The white in my fingerprint ridges is powder from sticking my finger in the finer portion |
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Post by coastalrocketeer on Dec 23, 2017 13:51:36 GMT -8
(Questions for Karl below)
I would guess the finer portion is maybe 10% really fine powder... I did spend about 20 minutes trying to "grind down" the bigger grains with the 1/3 cup of powder in the pestel and mortar, but decided that doing that would be too labor intensive for any larger amount of binder...
I think my next option is to look for a finer screen so I can select out the finest portion for higher reactivity as binder material... Optimally would want to find a screen size that selected the right percentage for binder...
I intend to pick up some rock wool/mineral wool insulation to use as the fiber reinforcement/crack preventative material, but have to make a 3 hour round trip to the valley from where I live on the coast to find it.
A few questions for you Karl... Because I have a hard time keeping all the posts about different materials that are usable and methods that apply to them straight...
1) If using all zeolite as both binder and aggregate (as opposed to other aggregates) and using finest fraction as binder, and sodium hydroxide NaOH as alkali gelation agent, I need 7% or more of my total dry ingredient weight to be lye, and if doing 3:1 zeolite:lye binder that would dictate 21% of the total zeolite and lye weight for my mix, including the "aggregate portion" would be the amount of Zeolite to use as binder, and with 4:1 it would be 28% of total dry ingredient weight that becomes the "binder portion" of the zeolite... Am I understanding your ratio recommendations properly as applies to my choice of materials for this next experiment?
2) I really like the idea of making a thin enough binder to use in a couple of ways... A more pasty one like mayonnaise, that could be spread with a rubber spatula onto surfaces as a refractory surface sealer/rigidizer/lining for ceramic wool and rock wool, as well as used like epoxy in layered build ups with cheese cloth, burlap, or similar materials, and another like a thin gravy that one could saturate mineral wool, and then be mostly removed by centrifuging most of it off to leave a thin geopolymer coating over the mineral wool structure... Is any of this possible with a pure Clinoptilolite zeolite binder? I presume if it is, highly micronized particles for the binder portion would be fairly critical.
3) Is acid activation useful at all with a pure zeolite binder? (make it more hollow/porous/reactive before alkali addition?) (I have phosphoric and acetic acid laying around to experiment with)
4) I have a 4 lb bag of the sodium metasilicate "red devil tsp90" phosphate free TSP substitute as a source of water glass... Did not use this in my original mix... A solution if I t WAS however, soaked into half of the scrap that I put into the wood stove, just to see how it would soak into the already "sintered" piece, before I put it in the wood stove. (600g/litre solution). How would I use this solution in any of these Clinoptilolite mixes? Could I use it as the water I add at some stage/s of mixing the binder?
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