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Post by Vortex on Mar 20, 2017 1:57:13 GMT -8
Some of these recipes mention "powdered Waterglass". Is that a commercial product? Yes, search for Sodium Silicate Powder. |
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Post by firewatcher on Mar 20, 2017 16:15:02 GMT -8
I made some clay and silicate bricks two weeks back and I didn't add water I just varied the silicate amount. I only added silicate no hydroxide. I think the mix I made needs extrusion. When I put the samples in the oven they get very soft. Softer than they were before the heat. I removed them and the drier mix is now no longer pliable. I will fire it soon. Last year I tried to geopolymerise the same clay with silicate and hydroxide at ambient temps and I failed... (I left the brick out in the rain and it fell apart) I will definitely try this new recipe out and give feedback, I have all the ingredients. I think this one needs Karl's critique though... Hi lawry, I read through the material a few times but didn't come away with a specific "recipe" to try...did I miss something or did you get access to the full article which tells proportions of "ingredients"? |
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Post by firewatcher on Mar 20, 2017 16:27:00 GMT -8
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lawry
Junior Member
Posts: 113 
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Post by lawry on Mar 20, 2017 22:13:42 GMT -8
Hi lawry, I read through the material a few times but didn't come away with a specific "recipe" to try...did I miss something or did you get access to the full article which tells proportions of "ingredients"? Hi firewatcher. I was gonna wing it... đ Here is an article that is accessible which talks about the same process. It has "a recipe" The final curing temperatures are impractical for me though. The highest I can get is 320C www.researchgate.net/publication/263776475_In-situ_carbonation_of_alkali_activated_fly_ash_geopolymerI use an app on my phone for quick molarity calculations. I always use 14M Sodium Hydroxide for Fly Ash. |
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Post by coastalrocketeer on Mar 31, 2017 11:13:15 GMT -8
If I am remembering right from Karl's geopolymer forum, I believe that would be sodium metasilicate...
Sold as Red Devil TSP 90 cleaner in the paint prep section at my local ace hardware...
This permies forum post discusses it...
Has to be dissolved in a KOH or NaOH solution, and the reaction is exothermic... So add slowly.
People also apparently use amorphous silica and silica crystal kitty littler as feed stocks.
Lots of videos on YouTube of the mixing process, which should be similar for all.
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lawry
Junior Member
Posts: 113
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Post by lawry on Mar 31, 2017 13:32:24 GMT -8
I use cat litter as well...
I have been dying the baking soda clay brick. I will fire it tomorrow then put it in water on Sunday to confirm if it has geopolymerised
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Post by coastalrocketeer on Mar 31, 2017 18:35:35 GMT -8
My local pottery supplier sells amorphous silica which is presumably ground finer and is $40 for a 50 lb bag and has none of the additives of the kitty litter, but I'm told can be used the same way.
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Post by pigbuttons on Mar 31, 2017 19:40:32 GMT -8
Great thread. I did an experiment with a recipe from the "Geopolymer" book. The problem was that I didn't know how to do the mole conversions so I just winged it with straight gram ratios of the ingredients. Then I found this site: www.convertunits.com/from/mole/to/gramThe block ( 4" x 3" x 3.5" ) produced was wet cured ( 72 hours ), then air dried ( 4 days ), then cured in my oven at the 200*F setting ( 12 hours ). The result has been fired a few times in my rocket stove and is holding up nicely. I did find that the outer shell is more durable than the interior because I scratched through the outer shell and found that the interior is a little crumbly. Although not as insulative as the stove's vermiculite and calcium aluminate body, the block was still cool to the touch on the side away from the combustion chamber when the interior of the combustion chamber was glowing yellow hot. 900 ml fine grain vermiculite 120 ml red fire clay from a ceramics shop 180 cc H2O from a high grade water filter but not distilled 17 gram NaOH from lye 11 gram Alumina ( calcinated ) from a ceramics shop 50 gram Silica from kitty litter I mixed the NaOH in the water, then added the Silica and mixed until dissolved ( over an hour, grinding first is recommended in the future), then added in the Alumina. In a separate container I mixed the red clay and vermiculite, then added only enough water from the tap to get the mix to clump when squeezed tightly. I poured the solution into the vermiculite/clay material and blended with a paint mixing paddle and a drill for 20 minutes. The result was a moist but still crumbly consistency. This was then pressed into a mould that was lined with kitchen plastic wrap. The biggest take away from this is that even with wildly mismatched ratios, reasonable results can be achieved. |
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Post by SteveStuff on Apr 1, 2017 15:00:24 GMT -8
Good Stuff Pigbuttons! Thanks for the recipe!
Basically what you came up with is fairly insulative so may be good for riser and burn tunnel (in a J), but would probably not handle the abuse of the wood load?
Also, "not as insulative as the body", what is the body made of? or should I say, how did you build it?
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Post by pigbuttons on Apr 1, 2017 19:16:52 GMT -8
The body is cast using vermiculite and Calcium Aluminate cement in a 4 to 1 ratio. It is a long horizontal burn tunnel, square 4" J-tube, cast into a steel box, with a steel feed tube attached, and a steel riser. I still have some work to do on it to finish up the this prototype. The first prototype was made with Portland cement and it still works fine but is starting to crack somewhat in the area of the burn chamber.
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