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Post by pigbuttons on Mar 17, 2018 14:12:54 GMT -8
Well for some time now I've been experimenting with the geopolymer stuff and although rather fun, I don't have the chemistry background to bring it to fruition. So I found a refractory company about 90 minutes away that sells Kast-o-lite 30 for $45 for a 55 pound bag. This is significantly cheaper than I could make geopolymer what with shipping of the ingredients and all, plus my time and energies for testing etc. I did a small test batch yesterday: it wet cured in 16 hrs, is as hard as regular portland based concrete, as of yet is showing no signs of shrinkage or cracks. I'm getting ready to try and heat cure it up to about 500F. I'll let you know how it goes. Here's the recommended usage sheets: Kast-O-Lite instructions |
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Post by pigbuttons on Mar 17, 2018 19:51:40 GMT -8
In my wife's oven I started out at 300F and an hour later took it to 375F, then an hour after that to 500F for 30 min. It stays hot longer than I would have expected, but in order to get the consistency to properly mould into the form I needed 13 times the minimum amount of water. Even at that the stuff was still far to the dry side of plastic. There is the slightest appearance of shrinkage away from the steel mould (I would guess less than 0.0005 of an inch, and then only on two sides), no cracks, no flaking, it is still as hard as portland based concrete. It is probably important to note that this product is designed to be used as is with no amendments, or fillers, or aggregates, or admixtures. Think of it more like quickrete than portland cement. It contains sand, fiber, and some light weight aggregate that is not listed individually on the MSDS.
So here are some numbers:
Kast-o-lite 30 6.31 oz
Water 0.95 oz
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Total weight 7.26 oz (wet)
yielded volume 8.6 cu in
Cured weight 6.64 oz ( would indicate that 0.62 oz of the 0.95 oz of water, or 2/3, was driven off during the curing process.)
That works out to 0.772 oz per cu in.
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Post by keithturtle on Mar 17, 2018 20:45:17 GMT -8
I use the kast o lite 26 because that's what I can get locally, and it's cheaper. I built a vibrating table very much like this one www.youtube.com/watch?v=GWImU7CCU8gI used an old misfit 1/3 hp motor 1725 rpm with a slightly eccentric weight on the shaft, works great and makes the thicker mix settle into the form without having to add too much water. Make sure that rascal is level before you pour Man that stuff sets up quick! Turtle |
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Post by pigbuttons on Mar 18, 2018 5:57:46 GMT -8
I use the kast o lite 26 because that's what I can get locally, and it's cheaper. I built a vibrating table very much like this one www.youtube.com/watch?v=GWImU7CCU8gI used an old misfit 1/3 hp motor 1725 rpm with a slightly eccentric weight on the shaft, works great and makes the thicker mix settle into the form without having to add too much water. Make sure that rascal is level before you pour Man that stuff sets up quick! Turtle Thanks for the link Turtle, that looks like even I could make one. I had a small hydraulic motor with a weight welded to one side of the pulley that worked well but I don't know where it went. I hear what you said about the 26 vs the 30 but 30 is what they use and they typically don't sell retail, they are a furnace repair company. I was only the second retail customer in the last 10 years. The other guy was building a pizza oven. You are right on the fast set up. They recommend no more than 3 minutes of mixing, and then placement with 20 min. That tends to limit batch sizes quite a bit but I'm hoping to figure out all the details here soon. |
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Post by etownandrew on Mar 18, 2018 14:21:14 GMT -8
Well for some time now I've been experimenting with the geopolymer stuff and although rather fun, I don't have the chemistry background to bring it to fruition. So I found a refractory company about 90 minutes away that sells Kast-o-lite 30 for $45 for a 55 pound bag. This is significantly cheaper than I could make geopolymer what with shipping of the ingredients and all, plus my time and energies for testing etc. I did a small test batch yesterday: it wet cured in 16 hrs, is as hard as regular portland based concrete, as of yet is showing no signs of shrinkage or cracks. I'm getting ready to try and heat cure it up to about 500F. I'll let you know how it goes. Here's the recommended usage sheets: Kast-O-Lite instructionsSo your comment made me curious about how much my current planned geo-polymer mix cost per pound. So I added it up and came out at $0.19 per dry pound. This assumes free clay dug out of the ground. However, you are right about the fiddling time doing tests and trying to work it out. If I added that it would be way higher. Also, I have not yet gotten to the end of my project and it might not work out. |
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Post by pigbuttons on Mar 18, 2018 19:27:09 GMT -8
Well for some time now I've been experimenting with the geopolymer stuff and although rather fun, I don't have the chemistry background to bring it to fruition. So I found a refractory company about 90 minutes away that sells Kast-o-lite 30 for $45 for a 55 pound bag. This is significantly cheaper than I could make geopolymer what with shipping of the ingredients and all, plus my time and energies for testing etc. I did a small test batch yesterday: it wet cured in 16 hrs, is as hard as regular portland based concrete, as of yet is showing no signs of shrinkage or cracks. I'm getting ready to try and heat cure it up to about 500F. I'll let you know how it goes. Here's the recommended usage sheets: Kast-O-Lite instructionsSo your comment made me curious about how much my current planned geo-polymer mix cost per pound. So I added it up and came out at $0.19 per dry pound. This assumes free clay dug out of the ground. However, you are right about the fiddling time doing tests and trying to work it out. If I added that it would be way higher. Also, I have not yet gotten to the end of my project and it might not work out. Yea, digging your own clay may save money, but consistent results are going to be difficult IMO. Even with calcined kaolin from a well known manufacturer results were challenging at best. .. |
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Post by keithturtle on Mar 18, 2018 19:28:13 GMT -8
Geopolymer research has a great benefit- if the possibility of buying any sort of castable goes away, at least we can make it. It is good to have a workable geo recipe stashed away, along with sources for the materials needed
IMO
Turtle
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Post by keithturtle on Mar 18, 2018 19:31:21 GMT -8
I leaned on a castable supplier for a bag of AC, alumina cement. The smallest quantity he would sell was half-skid of 20 bags.
Not ready to commit to that yet, since the stuff has a shelf life unless stored in controlled environment, I'm told
Turtle |
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Post by Vortex on Mar 19, 2018 2:26:17 GMT -8
Keith, I stored a small bag in my house for nearly 10 years and it was still useable, and I live in Ireland! I have about 30KG here now that I've had in the house for 18 months and it's as good as new.
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Post by pigbuttons on Mar 19, 2018 5:33:46 GMT -8
I share your concern Turtle, and I loved the idea of a potential DIY refractory, but reality is "I", repeat I, don't have the requisite skills. And I'll continue to follow the progress of those brave souls that continue to search for the holy grail recipe. When they find one that has real world potential, I'm there, absolutely, I'm there.
By the way, Calcium Aluminate cannot withstand the temps of a good rocket stove. Been there and it starts to turn to dust after a couple of months. It is much better than Portland Cement which tends to start spalling, but still not much of a long term solution. It does store well in powder form if you have somewhere that stays below 60% humidity and you keep it closed up in something like a thick 3 mil garbage bag.
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Post by Deleted on Mar 19, 2018 6:11:26 GMT -8
if you stuff Kast-o-lite with a lot of vermiculite like you did with geopolymer
then failure is guaranteed.
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Post by Deleted on Mar 19, 2018 7:13:01 GMT -8
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Post by keithturtle on Mar 19, 2018 21:22:01 GMT -8
Yeah, it's my understanding that any formulated castable gets used straight-up, nothing added but water. That's the only way I'll use it.
For the record, my planned DIY castable will be 1 portland, 1/2 fine mortar sand, 1 fireclay and 4 finely seined perlite. Haven't made any pucks or parts with that mix yet, and I'm open to suggestions on ratios
Turtle, still at it
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Post by pigbuttons on Mar 31, 2018 20:07:04 GMT -8
Ok. So it's been about two weeks since I made my test batch. After baking to 500F for about two hours it was very hard and has not changed in two weeks of sitting in mildly humid conditions, only weighs as much as the Kast-o-lite ( I'm assuming that the water mostly evaporates), and although not water soluble, water is absorbed into the material. After awhile it drys out and returns to its dry weight. I cannot detect any shrinking or expansion, no cracks or even the slightest crazing. In my opinion this is an excellent castable refractory. The final test will be when I can find the time to build a full working stove and then abuse it for a couple of months.
As far as the water absorption, I'll be contacting the refractory repair company where I bought the kast-o-lite and see if they have any recommendations.
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Post by pigbuttons on Apr 3, 2018 18:39:24 GMT -8
The response from the local expert was that the kast-o-lite 30 must be cured to a min of 800f for one hour to fully lock the mechanical binders. After that it should be impervious to water infiltration.
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