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Post by ronyon on Dec 21, 2013 19:35:18 GMT -8
I was thinking that clay with rock wool fibers could be cast as a core without insulation such as perlite and it would be stronger. Most designs add an insulating layer anyway, so why try to force the material to do yet another thing?
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Post by Donkey on Dec 23, 2013 9:34:43 GMT -8
Good point.. It's certainly worth a try.
I bet it could be done quite thin and still be strong enough to handle a little abuse. Like shipping..
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Post by Rinchen on Dec 24, 2013 2:21:42 GMT -8
The rockwool in clay will add strength, but not insulation.
Its the airpockets that will provide insulation and when you mix it into clay, you will loose the airpockets.
I would be interested to know how strong it will be. It might just make an excellent mix to make liners and heatrisers with.
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Post by ronyon on Dec 24, 2013 12:55:40 GMT -8
Yeah, I think this will be my riser and batch box , with loose perlite around them.
This appeals to my Lego mentality, which always plans for dismantling and re-use.
I think a porcelain clay would be best.
Still local-sourcing that...
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Post by talltuk on Dec 26, 2013 12:19:52 GMT -8
I was interested in using this in insulating cobwith perlite or vermiculite, using rockwool or glass fibre instead of straw. Wasnt sure how it would hold up to heat.
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Post by oboblomov on Jan 9, 2014 8:50:05 GMT -8
Sounds like a really good idea. I have several questions: - Any suggestions for ball park proportions of rock wool:fire clay?
- I may not know precisely what you are calling rock wool. I assume it is fiber made from basalt, but not sure. I have some Roxul(TM) bat insulation, but ripping it up strikes me as an unhealthy operation. Their website says they also market (in Canada if not in US) something called Rockfill that seems more suitable. Am I looking in the right direction?
- In casting clay/rock wool objects, is it necessary to add some sort of grog -or- should I experiment along these lines?
regards -- obob |
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Post by ronyon on Jan 19, 2014 23:00:37 GMT -8
Roxul is what I will use, wetting it thoroughly before starting. Other than that I am going to make it up as I go. Turns out Red Devil makes a "TSP" that is actually Sodium silicate, so that will be going into my water, followed by the clay and fibers, alternately till it seems "right".
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Post by pianomark on Mar 29, 2015 18:31:22 GMT -8
Ronyon,
Have you (or has anyone else) followed up on this idea? I have been experimenting with roxul, backyard clay, and sand, made into pucks, dried thoroughly, and tossed into my woodstove for multiple firing cycles. My results look promising, seems to be strong, somewhat lightweight and I haven't seen any melting, flaking or spalling. Even if a larger casting cracks, it seems that the fiber should hold it together. I hope to test some pucks in a real kiln soon, at higher temperatures.
The hardest part was getting a homogeneous mix. The roxul really resists absorbing moisture. One method that worked for me was cutting the roxul batt into 1 inch cubes with a machete, then mixing with a potato masher into clay slip, getting all the lumps out, and adding the sand last. The trick is breaking up the roxul and working the slip into it so there are no dry lumps (air pockets). I haven't tried it with perlite in the mix yet. I imagine larger batches could be mixed like traditional cob, with the feet.
Just wondering if anyone else has tried this.
Mark |
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Post by ronyon on Apr 1, 2015 21:46:41 GMT -8
I have a core built,it suffered from not enough clay,'tis crumbly and I have yet to fire it...
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