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Post by coastalrocketeer on Jan 29, 2018 13:51:45 GMT -8
The dissolving lye delivers quite a lot heat and one can use hot water for the mix. As a safety aside... I had one mix where I had the lye sitting in a mound on top of the binder feedstock and added hot water... So much heat was created in the already close to boiling water as it dissolved the lye, that a good portion of it boiled off violently, and if I'd been a bit closer, I might have gotten super strong lye water spattered in my face by the rather violent boiling... So definitely be cautious and heed Karl's advice to mix the lye into the binder feedstock powder before adding water, or mix just enough water in to make a paste and then stir in the lye powder. I believe he has stated that pre mixing feedstock powder and lye is the best method as water demand to create a paste is minimized, and thus lye concentration and mineral dissolution reactions are maximized. |
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Post by esbjornaneer on Jan 30, 2018 0:28:53 GMT -8
Coastal, your first and last statments are correct. Mixing feedstock powder with water to a paste is just in order to know how much water it too much! (I had been using too much water in _all_ my clay binders which was the reason Karl came up with the way to get me to use less  I had been focussing too much on water dissolving the NaOH rather than giving it time.) |
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Post by coastalrocketeer on Jan 30, 2018 20:31:30 GMT -8
I am currently trying Karl's advice of using phosphoric acid to pretreat my zeolite and produce extra reaction heat, as well as using as little water as possible. The zeolite is nice because the water seems to spread VERY evenly through it.
I can stir 50 grams of water into 500g of zeolite and it remains a "powder" but the water becomes evenly distributed quite quickly just stirring with a knife... So trying adding water 50 grams at a time after stirring the lye in with the first 31.25 grams of water with 18.5 grams of phosphoric acid 40%...
EDIT: Which should have given me about 1.5% of my binder's dry ingredient mass as phosphoric acid, per Karl's advice elsewhere for obtaining extra heat... Unless I was supposed to use 1.5% strength phosphoric solution to minimize reaction with the zeolite and have it all react with the lye.. It fizzed which presumably used up some of the acid, so maybe I understood wrong
Not even going to paste consistency until I have let it rest in a 180F oven at this high concentration for a bit
EDIT: A bit turned out to be a couple of hours in the oven with me adding water 25 grams at a time... And then letting it sit in the oven for a while longer...
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Post by esbjornaneer on Jan 31, 2018 0:47:45 GMT -8
Wow that is a little water! Can you be a bit more specific about how long 'a bit' is? And maybe add that info to your zeolite/SweetPDZ thread where it will be more use for future readers  I'll start a new thread about my fire clay experiments over the next few days to not make this thread clogged with the fire clay info too. |
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Post by coastalrocketeer on Jan 31, 2018 6:03:34 GMT -8
Wow that is a little water! Can you be a bit more specific about how long 'a bit' is? I added water when it seemed to be getting too thick.. Edited my post above to answer your Q and provide some additional info, and will be posting about all of my latest experiments in my thread soon. |
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Post by branja on Jan 31, 2018 9:51:38 GMT -8
Dont forget the 60% of H2O in 40% acid. H3PO4 is used for Fe complexing,your zeolite probably dose not have much Fe.Acid delamination works with layerd clays,zeolite is not layerd.
What is the purpose of H3PO4,im interested?
I only see Ca reaction with H3PO4
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Post by coastalrocketeer on Jan 31, 2018 11:40:32 GMT -8
Dont forget the 60% of H2O in 40% acid. H3PO4 is used for Fe complexing,your zeolite probably dose not have much Fe.Acid delamination works with layerd clays,zeolite is not layerd. What is the purpose of H3PO4,im interested? I only see Ca reaction with H3PO4 Thanks for the reminder and question :-) Yes, the ratio of water and acid was taken into account... When figuring out total water and acid for the purpose based on the total quantity of binder feedstock. It was a suggestion from Karl to create extra heat when the lye is added, for more complete dissolution of the zeolite, rather than for breaking down the zeolite it's self... Which I had been having issues with using a zeolite "powder" that is really more granular. I don't want to clog up this thread with more discussion of zeolite which is OT... I'll be updating my zeolite thread as soon as I am done with 3 new test batches. |
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Post by esbjornaneer on Feb 1, 2018 0:38:01 GMT -8
Some pictures and reporting on the attempts I did before moving on to fire clay: I made 7 samples in total with launa so far. I did not rest the binder for any of them and mixed in too much water while making the binder. Sample 1 & 3-6 all dissolved in water after only curing at room temp. (Karl has since said that samples may not pass the 24hr water test when cured at room temp only.) Sample 2 was too wet when I un-moulded the others so I forgot about it and when the other 5 had dissolved in the water I thought it will never survive the water test. So I stuck it in the fire box of my 150mm BBR for a fire to see what it would do. It survived the fire box and then survuved 24hrs soaking too. post fire, pre soaking 2 pics:   post soaking then dried again 2 pics:   I have now done a plumbers blow torch test. I only continued for 10 minutes per sample. As a guide line I torched a RA heavy fire brick to see what would happen. After 10 min the back of it had reached 130degC while the flame side was fluctuating 650-850C on my IR thermometer that is rated to 700C. The flame side was glowing orange, the laser pointed at the centre of the flame. The torch was turn on full and the distance to sample was adjusted so that the tip of the innermost/pale blue part of the flame was touching the sample. Sample 2 rated the same on the torch side and also on the back 130C (I noticed when testing 2 more samples that unless I was careful I may have picked up the temp of the support/platform I rested the sample on so this temp may be faulty, may test again another day and edit this number). clay/lye in binder % binder in sample % fibre in sample (all % of dry weight) % water in sample Sample 1 1 20 0.1 40.6Sample 2 1 40 0.1 40.6 Sample 3 2 20 0.1 40.6 Sample 4 2 40 0.1 40.6 Sample 5 3 20 0.1 40.6 Sample 6 3 40 0.1 40.6 Comments/improvements of the torch test, etc., welcome! EDIT: I redid the torch test and cam out with a back side temp of 88C for Sample 2 after 10 minutes. |
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Post by esbjornaneer on Feb 1, 2018 0:54:09 GMT -8
Sample 7 was the first I tried to dry quicker than on the bell of my BBR. I put it into the solar oven I have and left the door slightly open. It would easily have reached 125C/250F during the day. That night I left it in the oven, outside, and there was a frost. I don't know how wet the sample was when the frost arrived but it was still in the mould. Later in the day I de-moulded it and left it in the oven with the door still slightly open for another 24hrs (total ~48hrs). Then removed it and left it on an outside window ledge, protected from water. After I came back to it after several more days hovering around freezing at night it looked like this:   clay/lye in binder % binder in sample % fibre in sample (all % of dry weight) % water in sample Sample 7 1 20 1 40.6 Torch rest like in my previous post gave a result of 100C on the back after 10 min, same temp on flame side as previously 650-850C. Can anyone comment on why the big cracks? Potential freezing, too fast drying, or something else? EDIT: I redid the torch test and came out with a back side temp of 60C for Sample 7 after 10 minutes. |
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Post by esbjornaneer on Feb 1, 2018 1:08:27 GMT -8
NOT LAUNA!! I am adding a report on my sample 8 here even though it was not using launa/expanding clay, but a pottery clay I was given by a friend. I have no idea what the mineral composition of this clay is. The reason I am including it in this thread is that it was cured the exact same way as sample 7 above but did not experience the same level of cracking.   clay/lye in binder % binder in sample % fibre in sample (all % of dry weight) % water in sample Sample 8 1 20 1 58.5 Torch test: this is where I thought of holding up an ambient temp piece of writing paper in front of the fire brick tower I was resting the samples on when reading the temp. I then moved the IR thermometer up and down until I got the highest reading on the back of the sample: 62C after 10min, while flame side was still 650-850C. This sample is still crumbly, like sample 7, but not as much. Next on to fire clay experiments. |
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Post by branja on Feb 1, 2018 4:53:26 GMT -8
esbjornaneer , nice, it is good to do experiments. You have just meet the demon called "efflorescence" , get used to it. Try to make the clay a smaler particle sample, intruduce more heat and reduce the Na mass/ total clay mass ratio.Reduce water even more. As it is mentioned before (by the "fater"  )with your type of non reactive clay you need less Na in a total mass and les any liqids. Try a bit more of reactive substances like CaOH, phosphorus acid, portland cement. Visual (from pictures) says "too much of Na salts", I was there. GP-s are cured for a month at least ,then are put in a fire (above 250C). Recheck the NaOH / Si-Al solids ratio. Dont take me too serious , just a thought. My first try had a 2cm crystals on it, and cracked all over. , keep it going
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Post by esbjornaneer on Feb 1, 2018 9:04:59 GMT -8
branja than you for your comment and suggestions. I will take them into account when I get back to the launa experiments. And are you saying that the torch test is of no interest until the 'one month + 250C firing' have been done either?
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Post by coastalrocketeer on Feb 1, 2018 22:05:44 GMT -8
Great posts E! Glad we have Karl and Jura here to give advice. One thing I will say about cracking, is that in my mixes adding a lot more than a few percent Rockwool fibers prevented that in a VERY high water mix that was like clay slip when I added the mineral wool. I am approaching it from using the mineral wool as a volume increaser, and to compensate for the extemely high water demand of the sodium bentonite clay I am using. The demand is lower when the bentonite is mixed with the alkaline binder solution and aggregate water, than when bentonite and water are mixed alone, and the bentonite does not seem to dissolve/mix in fully in an alkaline solution. Here's pure betonite with 5x as much water by weight (a consistency/water demand test) after 5 or 6 weeks of air drying on my porch...  |
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Post by esbjornaneer on Feb 2, 2018 0:56:03 GMT -8
Thank you for your pic Coastal, I think you mean Branja rather than Jura as there is no post from Jura in this thread anyway I thought it might have been the (potential) freezeing that generated the cracks but will have to replicate to see, but not for a while. But you are saying that with more fibres it would crack less if it is due to the shrinking of the clay. Karl said somewhere that he has used as much as 20% fibre at times (with other feed stock), but mostly recommend 1-3%. |
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Post by branja on Feb 2, 2018 4:41:39 GMT -8
branja than you for your comment and suggestions. I will take them into account when I get back to the launa experiments. And are you saying that the torch test is of no interest until the 'one month + 250C firing' have been done either? In my expirience (my 2 cents-im not necessarily right). How to cure: step 1: totally disable water lost (foil wrap,tupperware box,packaging tape or similar mechanisam) step 2: enable water lost (unpack, let it breathe) step 3: bake it (burn or whatever is your style) increase temperature slowly (see about chamotte & pottery delta temperature per delta time) For "unknown clay", which also makes efflorescence, you need longer time in my opinion. For reactive clays (reactive materials in the mix) time form step 1 to step 3 can be less then a month. Small -micron size particles and reactive materials (metakaolin, portland , CaOH, CaO..ect) acelerate curing. Increasing curing temperature is useful but will not make curing time 5-6 days. So far as I rememberer karls "fastest full cure" was around a week (but those were reactive materials) Torch test is "final" after all curing is done, if you have H2O left inside the water expanding might cause cracking. |
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I had been focussing too much on water dissolving the NaOH rather than giving it time.)
)with your type of non reactive clay you need less Na in a total mass and les any liqids. Try a bit more of reactive substances like CaOH, phosphorus acid, portland cement.