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Post by coastalrocketeer on Feb 2, 2018 19:00:27 GMT -8
Oops! I did mean branja... sorry branja, and thank you E :-) Just saying that independent of Geopolymerization, because I'm not sure I'm even achieving that in my current mix, more fibers would be one potential solution where you want more crack resistance in a "high water demand" clay, or working with a higher water mix for other reasons, such as layered molding as used in epoxy and fiberglass. My latest mix was a so thin it was a paste that would partly settle out and separate from the clear liquid portion. VERY high water content. With enough fiber, which I just kept adding til it made the consistency right for molding by hand, the puck dried at 190F in the oven over two days with no cracking.  |
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Post by esbjornaneer on Feb 2, 2018 23:52:32 GMT -8
I have edited the original posts but will add here too:
I redid the torch test and came out with a back side temp of 88C for Sample 2, and 60C for Sample 7 after 10 minutes.
I should also mention that these muffins are about 30mm (25-35) thick and have a diameter of 50(back side) and 70 (top/torch side).
Coastal: what temp gradients are you getting with your torching (front//back temps)?
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Post by coastalrocketeer on Feb 3, 2018 13:37:34 GMT -8
That square puck above is also about 3.5 cm thick, and 19.5x19.5 cm... had my propane torch on it for a full hour and never went over 200F/93C on the opposite side in high humidity 55F ambient outdoor temps on my front porch. It actually LOWERED in opposite side temp after the first 15-20 minutes, as I believe the torch heat was still driving out residual moisture up to that point.
It has a volume of about 1300cc and weighs 883 grams. So weighs about 675mg per CC of volume.
I was not going for excessive strutural strength with this mix, but trying to achieve a cheap substitute for $10/sq ft LD ceramic fiber board.
This was cast from the leftovers of what was put on the mold I made...
Hopefully this evening I will find time to post some updates to my own thread and can answer any more questions you have there...
I was going for low density minimum necessary strength material, and presuming to get my insulative value from the entrained air spaces and reduced mass, as much as from particle boundaries, and the excess fiber reinforces the structure, increases volume
and allows for the high water content of the mix to exit without cracking...
In a lower mineral wool, lower water content mix, I would not expect it to increase volume the same way.
I think there is probably a balance to be found for any particular mix and feedstock/aggregate combination, where mineral wool is being used, to provide enough water dissipation/structural reinforcement, without using more than is necessary, or so much that it might somehow inhibit Geopolymerization....
Which, in my mix for this go round, it may very well be doing.
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