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Post by foxtatic on Nov 21, 2020 18:01:52 GMT -8
I've read that waterglass (sodium silicate)can withstand temperatures up to 1100°C. That's lower than basic CFB can withstand  I hit a sample of sodium silicate treated cfb with a 3000 degree f (2012c) yard torch. Full blast, glowing red. Had a nice hard feel and "plink" sound when dropped. Not a very analytical test, but that's my experience. The cfb on it's own desinigrates with that much abuse. |
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Post by Deleted on Nov 22, 2020 6:35:56 GMT -8
I've read that waterglass (sodium silicate)can withstand temperatures up to 1100°C. That's lower than basic CFB can withstand Waterglass is a chemically reactive liquid. Combined with a material of high alumina content the temperature of continuous use may well reach more than 1400°C.
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Post by Orange on Nov 22, 2020 11:32:32 GMT -8
thanks Karl, that explains it!
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Post by wrekinwanderer on Nov 23, 2020 12:49:20 GMT -8
Karl do you have an aprox idea of what ratio?
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Post by Deleted on Nov 23, 2020 13:31:42 GMT -8
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Post by Orange on Apr 11, 2021 10:23:19 GMT -8
tested few small pieces, this CFB is rated for max 1260C:  burned them with small torch for about a minute, I think it also reach max around 1250C. There was a bad burn smell comming (binders or whaterver chemicals) so that's not good. Here are the samples, from left to right: 1. untreated cfb 2. cfb top layer painted with waterglass 3. cfb whole painted with waterglass
4. cfb top layer painted with clay+sand 5. cfb whole painted with clay+sand
 Results: 1. untreated cfb - bit softer/weaker but not as bad as in foxtatic's video
2. cfb top layer painted with waterglass - hard top layer developed
3. cfb whole painted with waterglass - hard layer developed
4. cfb top layer painted with clay+sand - bit harder top layer developed but not hard as the waterglass
5. cfb whole painted with clay+sand - bit harder layer developed but not hard as the waterglass so I think it's defenetely worth coating cfb, even with mud. I don't know how much insulation value is lowered but I think not much since material is still very light. I think I'll paint all sides with waterglass and btw the one I used is like 30 years old  |
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Post by martyn on Apr 11, 2021 12:17:45 GMT -8
I have had better results coating ceramic fibre board with water glass after it has been heated.
I have found that coating the board before it has been heated cause the water glass to crack and peel off, water glass seems to work well on vermiculite, it does not stop it cracking but does harden the surface.
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