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Post by gadget on Jun 11, 2019 12:13:35 GMT -8
I picked up a bunch of fumed silica for another project. I was going to use some to make some rigidizer but I have not been able to find a recipe online yet. Anyone make any know some good ratios?  |
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Post by Deleted on Jun 12, 2019 8:28:27 GMT -8
2 NaOH + SiO2 = H2O + Na2SiO3 Na2SiO3 = sodium metasilicate 2 KOH + SiO2 = H2O + K2SiO3 K2SiO3 = potassium metasilicate Molar mass of NaOH is ~ 40 g/mol Molar mass of KOH is ~ 56.1 g/mol Molar mass of SiO2 is ~ 60 g/mol
See also: Basic Kaolinite Clay Geopolymer Chemistry
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Post by gadget on Jun 12, 2019 10:44:35 GMT -8
2 NaOH + SiO2 = H2O + Na2SiO3 Na2SiO3 = sodium metasilicate 2 KOH + SiO2 = H2O + K2SiO3 K2SiO3 = potassium metasilicate Molar mass of NaOH is ~ 40 g/mol Molar mass of KOH is ~ 56.1 g/mol Molar mass of SiO2 is ~ 60 g/mol
See also: Basic Kaolinite Clay Geopolymer Chemistry
Hey Karl, have you worked with any pure silica rigidizers? I'm looking for something without any fluxes in it. I am going to mix up some of the fumed silica I have with water next week and test it on some fiber blanket. I was hoping someone knew good ratios. I'm looking to surface rigidize and also completely rigidize some shapes. With the surface rigidizing, goal is to make it strong so as to add a face coat without mashing down the fiber. |
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Post by Deleted on Jun 13, 2019 6:23:03 GMT -8
Pure silica rigidizer depend solely on Van der Waals Forces. Highly dispersed silica required. I would not rely on that.
Just mix a small amount of your fumed silica with water let it dry and see if it satisfy you.
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Post by gadget on Jun 13, 2019 20:13:04 GMT -8
Pure silica rigidizer depend solely on Van der Waals Forces. Highly dispersed silica required. I would not rely on that.
Just mix a small amount of your fumed silica with water let it dry and see if it satisfy you.
From what I have read, it is the binder that is used in forming ceramic fiber shapes from loose fibers and is the best option for rigidizing if you want to retain insulating values. Just was never sure on ratios with water. So I did allot of digging and found some good info finally on some forge sites. ratio of about 3 parts powder to about 7 parts water seems to be a common average. One source said they use a cup of fumed silica to a pint of water with really good results. From what I have learned, it is a very good idea to soak the blanket completely if it is going to receive a face coat so that their is not any weak fibers under the hard shell. The idea is you don't want to crush the fibers underneath so they all need rigidizing. I'm going to be doing a fiber board burn chamber and what a strong face coat for bumps from wood loading. I will start a new thread once i start testing. Thanks for your input karl. |
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Post by smartliketruck on Feb 23, 2020 8:57:25 GMT -8
Have you found a satisfactory mixture for a ridgidizer yet Gadget?
I just picked up a kg of fumed silica for the steep price of $70 Cdn so I'd rather not use much with recursive testing.
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Post by Deleted on Feb 23, 2020 10:49:03 GMT -8
Have you found a satisfactory mixture for a ridgidizer yet Gadget? I just picked up a kg of fumed silica for the steep price of $70 Cdn so I'd rather not use much with recursive testing. One can perform tests with less than one g.
One should not use something just because some forge sites do.
I would rather use Kaolin - Glomax LL (Calcined) with phosphoric acid because it will not swell as much as with lye
or Grog - 200 Mulcoa with some lye or waterglass, can be made very runny.
A small amount of citric acid added to phosphoric acid makes it much more aggressive to ordinary clays especially red ones.
All a lot cheaper.
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Post by smartliketruck on Feb 23, 2020 11:59:38 GMT -8
I do have some Glowmax, 55% phosphoric and a few different organic acids including citric. So I can give it a try. The Glowmax never worked well for low temperature setting with lye for me I called Plainsman Clays (If I remember right it was Tony Hansen of digital fire) about it about it and turns out Glowmax is calcined at 900°C+ I apologize I'm going off topic here, I'll start a new thread in the Geopolymer subsection for further discussion and edit this post to add the link.
I started the thread here
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