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Author: Subject: xylitol + quicklime + water = cool putty
deltaH
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[*] posted on 8-4-2014 at 06:04
xylitol + quicklime + water = cool putty


I've discovered that one can make a fun and interesting mouldable grey plasticine-like putty that sets rock hard upon cooling to room temperature. I believe it may be an organic glass with a low glass transition temperature (a few tens of degrees C above room temperature).

Wearing heat resistant rubber or silicone gloves, one prepares it quiet simply by mixing (on a volume basis) two cups quicklime powder (calcium oxide), four cups granular xylitol (a sugar substitute sold in most supermarkets) and then adding one cup boiling water in a heat resistant bowl. Use a strong and large mixing spoon made from steel to mix.

After an initial delay, a violent exothermic reaction takes place that produces much steam and frothing (lime slaking). During this reaction I vigorously mix the thickening slurry with the strong spoon to break the large bubbles allowing the steam to escape and keeping the putty from mushrooming over the bowl. The reaction subsides quickly after starting.

After this you have a tacky grey putty. Keep mixing with the spoon, but it gets difficult as it firms up. At some point, wearing heat resistant thick rubber or silicone gloves, transfer a big lump of it into your gloved hand and begin kneading/working the putty in your gloved hands while it is hot. This is important! It takes some experience to judge the best stage when to transfer it into ones hands for kneading, do it too soon and it will stick to your gloves like crazy, too late and you will have a poor putty that crystallises and break apart forming a grainy mess. NB Knead well for a few minutes between you hands!

As you knead, it will take on the texture and feel of grey plasticine putty, very beautiful! While still hot, shape it into whatever shape you want, but be warned, it will harden if left to cool completely and you won't be able to shape it then (unless you reheat it). I suppose one could sculpt with it if you have a hairdryer to reheat hardening parts.

When you’re done, you can clean bowls, spoons and tools with hardened putty on it simply by soaking it in water for a few hours. It will dissolve leaving behind a fine lime powder slurry that is easily washed outside.

While initially slightly tacky to touch, this tackiness disappears after a few hours and your creations will resemble grey rock. It is also not hydroscopic.

Some properties:

    Very hard (doesn't scratch with nail)
    Glossy opaque light to dark grey depending on quicklime purity
    Not hygroscopic but not water resistant either in excess water
    Initially slightly tacky, but loses this in a few hours
    Brittle, will shatter if dropped!
    Shattered putty crystallises, it would appear, when re-heated.
    EXTREMELY bitter taste - a good thing so animals won't lick it :)

Some permutations experimented with:

    Other sugar alcohols (sorbitol and glycerine) result in a plastic or glass to crystalline phase transition quickly making powders. Glycerine caramelises somewhat and makes other unwanted by-products.
    Only xylitol seems to have a sufficiently metastable glass phase for this putty.
    I haven't tried erythritol, which might also work.
    Using slaked lime doesn't work.


[Edited on 9-4-2014 by deltaH]




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[*] posted on 9-4-2014 at 19:37


Quote: Originally posted by deltaH  

EXTREMELY bitter taste - a good thing so animals won't lick it :)


Are you implying that you made a mysterious putty and then TASTED it?
Well, either way, sounds really cool. I know I have to try this now. (Though I definitely won't taste it)
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[*] posted on 9-4-2014 at 20:32


Very interesting. I wonder if the Lobry de Bruyn–van Ekenstein transformation is involved. Have you tried with glucose?
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[*] posted on 9-4-2014 at 20:45


Do you have pictures? I might try this!
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[*] posted on 10-4-2014 at 04:47


Hi guys, I've been experimenting with this stuff for quiet a bit now, but destroyed almost every sample I made to explore what it can withstand etc and of course a thousand failures before I got it right, stupidly, I have nothing left but dregs, mostly crystaline powders because I purposefully induced crystallisation to see what not to do, but I promise to buy another packet of xylitol this weekend (still have lots of quicklime left) and make some more and take nice photos. I had some nice 'sculptures' (flat plates and stone shapped things) sitting on my fridge for a week, but then I also managed to destroy these experimenting with them :(

Sorry for the somewhat long winded explanation about making it, but I wanted to state everything I could think of that I learnt through trial and error so that people have the best results.

One thing I can add though is that the xylitol to quicklime ratio is somewhat flexible, 1:2 on a volume basis for powdered quicklime and granular xylitol works nicely, 1:1.5 also works, but gives quite a hard putty that is somewhat difficult to mould whereas the 1:2 is more plasticine like after kneading hot.

zts16, tasted only a miniscule grain on the tip of my tongue, figured at worst it would consist of calcium xylitol alkoxides, so wasn't too worried about toxcicity of such small amounts. But the extreme bitterness is useful as xylitol is very toxic to dogs and didn't want them eating my putty creations and then dying. Now I am not worried about this, because I think no animal nor human would ever eat this, the bitterness is EXTREME! I also have many ants around and they don't touch it either (does that infer something about the relative intelligence of ants and me :P)

Paddywhacker I've experiment using sugars, specifically I tried fructose and sucrose. They have a tendency to caramelise sometimes that the sugar alcohols sorbitol and xylitol didn't show (but glycerine does). Sucrose tends to make hard stuff rapidly (more crystalline, less glassy phase), so doesn't work well for a nice plasticine like putty. Sorbitol forms a similar putty, but on standing quickly reverts to powder mass that literally crumbles in ones hand. Xylitol can also undergo this crystal transition in this putty when nucleated, but it is far more stable and looks very stable from first preparation (without reheat). When I make more this weekend, I will save a sample for months and see if it crystallises.

I think during the slaking stage of the CaO, something more than simply slaking takes place in the pressence of the xylitol. I think in the pressence of the very high concentration of sugar alcohol, the CaO slakes but the resulting hydroxide is not crystalline or alkoxides form. I have confirmed that these putties don't form by heating slaked lime powder and the sugar alcohols, for example, there is something special about slaking the CaO in the presence of high concentrations of sugar alcohol that makes this work.

thesmug, by all means you should try it, it's great fun and very pretty and fairly safe. At least no bad smells. When the violent exothermic reaction takes place when the heating runs away, only steam comes off and there is a faint pleasant sweet smell in the air from the xylitol.

If you want a light grey putty in the end, DO try to source a very good quality calcitic burnt lime. I managed to source a sample of fantastic lime eventually, but my initial batches were dark grey because of impurities.

I would love to see people post some little paper weight type sculptures made with this stuff. I'm not very artistic unfortunately :(

It's tricky working with it though when it's so hot, I used dishwashing rubber gloves, but these are two thin and while one doesn't get seriously burnt with them, it is unpleasant to say the least, especially the kneading stage.

I have heard though that one can buy silicone gloves that are very heat resistant but still give one good hand feel, I'll be looking out for those, failing that, slightly thicker rubber or two pairs may do the trick nicely.

[Edited on 10-4-2014 by deltaH]




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[*] posted on 10-4-2014 at 04:59


Another source for your lime is pickling lime found in most stores that cater to people who can food. This is food grade so I would assume it would be fairly pure.
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[*] posted on 10-4-2014 at 05:02


Thanks hypalcon, is pickling lime unslaked though, because slaked lime doesn't work for this putty unfortunately. Well to be more precise, you can make some sort of putty with slaked lime, but it doesn't have the same extreme glassy hardness upon cooling.

In Cape Town (where I live), finding good quality unslaked lime powder was very hard. I had to have a sample sent to me from a quarry/limeworks in a town a few hundred km's away. It was not locally available, only several types of slaked limes were and one very bad quality unslaked flakes.

One other thing, would somebody who has access to erythritol in their country please let us know if this works as well? I can't find any OTC erythritol in South Africa. I think that will then cover just about all the common sugar alcohols that I can think off. Polyvinyl alcohol might also be quiet good for these putties (technically not a sugar alcohol but similar), if not in pure form, then as an additive to prevent crystallisation.

[Edited on 10-4-2014 by deltaH]




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[*] posted on 10-4-2014 at 06:05


deltaH:

All this is quite interesting. Have you any idea of how temperature resistant this material is? Does it soften/melt/char/whatever on strong heating?

I'm thinking of those poor sods that have to prepare benzene from benzoate/hydroxide, usually using empty metal paint cans. Could this be a possible cheap sealant for these primitive 'retorts'?




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[*] posted on 10-4-2014 at 07:20


hi blogfast, it softens up when heated back to a putty, exactly how hot I can't say, 60-80C would be a guestimate, but I haven't measured it accurately I must say. Reversibility, however, in some cases may be very attractive.

Also, it can be 'dissolved' by letting it soak for hours. It is somewhat water resistant if you just splash or moisten it temporarily, but it won't take long immersed exposure.

In terms of sealants, because of it's hardness and ?strength?, it may be good to pack around joints you want to temporarily keep in place (e.g. glass joints) to reinforce them, provided the joint doesn't get hot. Afterwards you can remove it by soaking in water for a few hours or hairdryer to warm up the spot of putty and peal it off.

I wouldn't suggest reusing putty just yet because the crystallisation behaviour is not yet well understood, but seems like there is a danger of seeding that can set in when reusing and this can cause a disintegrating joint.

In any event, if one does this, I would exercise caution as this is very new untried tech, I suggest we experiment with it a bit more and then cautiously try some applications as we get a good feel for the stuff.

Again let me emphasise, if you make the stuff, knead/work it WELL in your hand before using, this seems to be very important for hardness and strength and preventing it crystallising.

[Edited on 10-4-2014 by deltaH]




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[*] posted on 10-4-2014 at 08:16


I didn't realise it softens so easily although 'putty' is a bit of a giveaway...



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[*] posted on 10-4-2014 at 08:48


If you have access to calcium carbonate, you can heat it strongly for a while to drive away CO2 and leave behind CaO.
Where I live, there is practically no topsoil, and it is basically a white limestone landscape that is primarily calcium carbonate (with some iron oxide impurities, etc). I haven't tried using it for calcium oxide yet, so I don't know how well it works, but I've prepared decent quality calcium chloride from it before.
If anyone else lives in an area with a lot of limestone, it's worth a try.
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[*] posted on 10-4-2014 at 09:08


Quote: Originally posted by zts16  
If you have access to calcium carbonate, you can heat it strongly for a while to drive away CO2 and leave behind CaO.


Do you realise what kind of temperatures and heating times are needed to produce significant quantities of quick lime that way?

Hint: it really only gets going from about 1000 C.

If you're hell bent on making quicklime from limestone, dissolve it in HCl, precipitate as Ca(OH)2 with a base, filter and wash. Ca(OH)2 loses its water from about 500 C.

[Edited on 10-4-2014 by blogfast25]




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biggrin.gif posted on 10-4-2014 at 11:02
Photos!


Right then, scaled it down to one third cup measures and now all done. Struggled to get the run away stage started today, i.e. where it mushrooms out and makes lots of steam. Either my quicklime's getting old or I am ;) Simple enough to solve:

microwaved on high for 30-40 seconds while watching it and stopped when I saw it started mushrooming and started mixing with spoon... from there on it goes on it's own steam (excuse the pun).

Anyhow, here are the pics with some descriptions, sorry, I don't have woelen's aptitude for photography :(

The batch today was pretty poor because I was impatient with the kneading. You might just see that the putty still has small white specks in it, this shouldn't be, though it does give it a nice look :D

Hope the photo essay helps!

xylitol and quicklime before mixing (638x478).jpg - 145kB all mixed - looks syrupy but no runaway yet (640x480).jpg - 135kB Got the slaking to start running away by microwaving (640x480).jpg - 150kB still puffing away (800x600).jpg - 258kB too viscous to mix anymore - ready to knead (640x480).jpg - 139kB starting to knead (800x600).jpg - 234kB done kneading (800x600).jpg - 292kB used a rolling pin to make a plate (800x600).jpg - 200kB

The kind of rubber glove I am wearing are terrible for the kneading stage by the way... they don't insulate one's hands enough and the putty is hot like hell!

[Edited on 10-4-2014 by deltaH]




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[*] posted on 12-4-2014 at 00:19


Thank you all for your comments and compliments!

Since it seemed to me that the putty I made above required further kneading, I decided to try a multiple reheat technique on my previously prepared plate, also to make sure it won't crystallise under repeated reheating (but not overheating!).

The microwave came in very handy again. I heated initially for about 30 seconds on high just to get the plate hot and malleable again from the outside inwards and then started to bunch it up by carefully folding in the outside parts followed by reheating for short bursts. There after, I applied 10-15 second reheats while every time taking it out and using a rolling pin, kneading it and folding it over. The rolling pin proved useful as when it's hot, my thin rubber gloves don't really give me the insulation I would like for hand kneading. This way was far more comfortible!

Anyhow, the point is that the microwave oven is your friend for reheating, but use it sparingly (short intervals of 10-15 seconds) or you may create hot spots that could destroy your putty.

After several repetitions, I got a fairly nicely homogeneous putty, it still had some specks in it, but this seemed to be impurities that there was nothing more I could do about, however, overall, the putty was quiet smooth and resembled, minus the small impurity specks, epoxy resin putty (for example, Pratley Putty if you guys know the brand).

Here is a final photo of a close up. The black and white specks are impurities present in the starting quicklime (it was after all a burnt limestone product). Overall, the putty is a light grey/off white colour, but this depends very much on the starting quicklime you will use.

Blogfast's idea of firing precipitated Ca(OH)2 is a good one if one has access to the necessary equipment and can reasonably exclude CO2 during a calcination.

While I have never done this, I would, however, suggest precipitating it from calcium nitrate (a kind of fertiliser) using ammonia solution and then let the slaked lime settle followed by decanting the supernatant water as it's difficult to filter such precipitates.

The residual 'slime' of lime is then simply dried by mild bake before calcining at 500C where the ammonium nitrate impurity will easily decompose to NOx and water during the calcination, so in the end, you should be left with a very pure calcium oxide powder, provided you did it in a kiln and not open so as not to have it exposed to CO2. If the calcium nitrate fertiliser is too impure, a recrystallization may be in order. One word of warning, NO2 is very toxic, so baking and calcination are not to be done unextracted indoors!

Either way, if you're not up to this, a bog standard commercial quicklime powder does, nevertheless, work for this application and some may even find the grey colour appealing :)

Finally, if your quicklime powder is quiet fine or very active, it may be wise to use cold water when preparing the putty to prevent too rapid slaking! You can always microwave the resulting syrup for 30-60 seconds on high or until it starts to mushroom out if you struggle to get the slaking reaction properly going by self heating.

Close up of set putty.JPG - 193kB

I am trying to name it something, so far the best I could come up with is xyca putty, pronounced zee-ka or z-eye-ka putty (I suspect American users would preffer the former). Could also write it as just zeeka putty in that context.

Please help by suggesting other names or comment on the existing idea for one

My wife just informed me that 'zaika', spelled зайка, means 'bunny' in Russian, as in an affectionate term a man might call a woman, rofl... oops!

Still like the name Zeeka Putty, even if it is my sweet bunny putty rofl!

[Edited on 12-4-2014 by deltaH]




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[*] posted on 12-4-2014 at 01:04


Calitol putty?Give credit if you use haha



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[*] posted on 12-4-2014 at 01:10


Quote: Originally posted by HeYBrO  
Calitol putty?Give credit if you use haha


Not bad, thanks, I had considered limatol putty as well, but I didn't like that it was generic for all 'ol's, wanted to make it xylitol specific, since sorbitol and glycerol don't really work.

If the erthyritol version also works, then we might call that kind Eca or Eka Putty?

******************

For those wanting to know the ratios I've used of quicklime powder to xylitol on a mass basis, it is pretty close to 2:3. General rule of thumb is that a little more quicklime leads to harder putties and vice versa.

[Edited on 12-4-2014 by deltaH]




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[*] posted on 12-4-2014 at 09:42


Geranic oxide is also commonly known as limetol. I wouldn't go with "limatol putty" as for me at least it would get me thinking of the other, completely unrelated chemical.
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[*] posted on 12-4-2014 at 10:05


Wow, thanks, Etaoin Shrdlu for that piece of info... agreed!



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[*] posted on 12-4-2014 at 16:50


Quote: Originally posted by blogfast25  
Quote: Originally posted by zts16  
If you have access to calcium carbonate, you can heat it strongly for a while to drive away CO2 and leave behind CaO.


Do you realise what kind of temperatures and heating times are needed to produce significant quantities of quick lime that way?

Hint: it really only gets going from about 1000 C.

If you're hell bent on making quicklime from limestone, dissolve it in HCl, precipitate as Ca(OH)2 with a base, filter and wash. Ca(OH)2 loses its water from about 500 C.

[Edited on 10-4-2014 by blogfast25]


Oh ok, thanks. Sorry for the irrational idea. I had not yet looked into the temperatures required, so I was unaware that they were so drastic.
Also, a few months ago my chemistry teacher mentioned to the class that one could produce CaO from CaCO3 using a normal grill… that was probably what put the idea in my head that the temperatures required were not too high.
In the future, I will check for details like that before posting.
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[*] posted on 13-4-2014 at 00:44


This is funny.
Last summer, I dissolved some plastic glue with boric acid and something else in water to make an interesting solid. This solid could bounce like a ball on the floor, especially if it was around 1cm in diameter. Later, this solid would harden and wouldn't bounce as much, probably because of some sort of cross-linking cycles.




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[*] posted on 13-4-2014 at 05:15


Quote: Originally posted by Eddygp  
Later, this solid would harden and wouldn't bounce as much, probably because of some sort of cross-linking cycles.


Cross linking suggests the material was polymeric to start with and polymeric materials become much more 'bouncy' after cross linking: see e.g. vulcanised elastomers v. unvulcanised (aka 'gree') ones.




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[*] posted on 15-4-2014 at 03:27
Crystallization problem in xylitol quicklime putty


Aw shoot... seems that crystallization is setting in to my hardened putty a mere couple of days after reworking it using microwave reheat (see photo). One can see a tumorous mass of white powder material forming and expanding from the edge. There are other smaller masses developing all over the show.

I will now be focusing my efforts on stabilizing the formulation.

My gut feeling tells me using a blend of polyalcohols/sugar alcohols may be a good way to go to depress the temperature of this phase transition.

Since sorbitol and glycerine showed very rapid formation of this white powder stuff upon reacting with quicklime, I would think they're not good candidates to blend with the xylitol. There's the off-chance that chelation by multiples of three hydroxyl groups favours crystalline products with calcium.

Again, I come back to erythritol, but since I have no OTC source for it in South Africa, that leaves me just one other option... glycols, either ethylene or propylene glycol (I'd prefer the latter due to its low toxicity).

So I will be substituting the water addition step in the preparation with the addition of antifreeze solution to my xylitol and quicklime mixture, using a little more than what I would normally have to make up the required water balance.

The fluorescent dye in antifreeze should add a nice colour to my putty :D

I'll keep thread updated with new findings and pictures as soon as I can!

Crystallizing.JPG - 173kB

[Edited on 15-4-2014 by deltaH]




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[*] posted on 10-10-2015 at 00:56


I'm intending to start some new experiments with regards to this old thread with the aim of improving these organic glasses.

To summarise, after experimenting with selected polyols (xylitol, glycerol, sorbitol and mixtures thereof), I determined that only xylitol gave a putty that crystallised slowly from the glass state, but it still crystallised after a few days induction.

I hypothesised that a combination of erythritol and xylitol might work better. Fortunately, I noticed erythritol on the shelves in SA for the first time the other day.

I also found a paper that determined the eutectic composition for an erythritol/xylitol mixture (see attached)... it seems like a good idea to use this mix. From the paper I quote thus:

Quote:
According to the results, the eutectic composition of the system
was found at an approximately 25% erythritol molar ratio, which
is equivalent to the 21% mass ratio. Its eutectic melting tempera-
ture was 83.9 1C. The melting enthalpy of the eutectic mixture was
found to be 248.7J/g.


Now before I used unslaked lime to introduce calcium into the system to make the putty harder and slow down crystallisation.

This time I'm going to try an interesting twist.

I have quite a bit of calcium lactate gluconate (CLG) left over from molecular gastronomy experiments. It's a high purity and very soluble form of food grade calcium.

CLG.jpg - 12kB

The lactate and gluconate anions seem particularly suitable for dissolving into a polyol glass with its unsymmetrical nature aiding the suppression of crystallisation and plasticization, so I'm going to try to saturate the xylitol-erythritol eutectic with CLG to get a TRANSPARENT product... hopefully.

It will probably be less putty-like since it would lack the calcium hydroxide filler and more glass-like, but I think this would be a cool new twist to investigate.

I'm hoping that a much higher dissolved calcium content in the polyol, combined with the eutectic mix, might make the glass stable w.r.t crystallisation, hopefully indefinitely.

Also, the glass should be edible, though it would give you a runny tummy from the polyols :) I think the bitterness previously was due to the lime.

Anyway, any thoughts and suggestions welcome.

Attachment: polyol eutectics.pdf (1.8MB)
This file has been downloaded 203 times

****************************************************
The authors of that paper attached investigated the eutectic for heat storage melts and noted in their conclusion that...

Quote:
However, experimental measurements performed by polarized
thermomicroscopy showed that the mixtures presented a low
crystallization rate, which limits their use in short term LHTES
systems. Additionally, the materials show polymorphism and tend
to form metastable amorphous states.


...which is encouraging for what I intend to do with it! I do believe getting more calcium into the glass phase is key to slowing down the crystallisation rate much further.

I would hazard a guess that the lime I previously used was only soluble in the xylitol putties to a very small extent, the remainder was just filler essentially.

Using CLG ought to raise the calcium concentrations significantly.

[Edited on 10-10-2015 by deltaH]




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[*] posted on 10-10-2015 at 05:44


Well, now I'm curious. Could this be used to make high-temperature reaction chambers (e.g. heating and crystallizing the whole thing to drive off the organics)? Or really anything that CaO could be used for (heat-resistant surfaces, etc.)?



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deltaH
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[*] posted on 10-10-2015 at 07:20


Thanks for helping to think of applications EC1 for I can't see many myself besides for it being surprisingly fun stuff to play with for some reason (inner child psychology at work?).

Unfortunately, the lime putty melts when heated :mad: so I can't see how it could be put to work in the fashion you suggest.

However, along the lines you are thinking, it might be possible to form it in the shape of something you want while it's a putty, then immerse it in say a saturated sodium carbonate solution overnight so that you dissolve out the polyol and convert the lime to calcium carbonate... and many variations on this theme of using the polyol as a soluble templating binder.

The problem is I tried this once but it doesn't work, the whole thing just dissolves into a soft mush of calcium carbonate. One needs the calcium hydroxide to crystallise in an interlocking fashion for this to work well. Maybe it simply required a higher lime ratio or some other condition specific trick, like doing it slower or something else, I don't know.

If I can make transparent glasses with calcium salts, it might have more applications.

Thanks for the ideas, keep them coming please!

[Edited on 10-10-2015 by deltaH]




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