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Hello!

Recently I was talking with another potter about AMACO's new "Cosmic Tea Dust" and "Aventurine." I mentioned that I loved the sparkles they have and she said it's just crushed mica. I know very very little about glaze so I was wondering if anyone has tried adding  mica to their glazes and what the outcome was? Did it any sparkle show through? If not, does anyone have other suggestions to get that sparkly twinkle into my glazes?

I use in-house glazes at my studio which fire to cone 5 for reference!

Thanks so much!

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Hi Mud!

No experience in my own work, nor have I seen any mica sparkle in person ...interesting

https://digitalfire.com/material/1018

Looks like low fire application; see also

     Specialized Techniques

      Mastering Mica

      by Kate and Will Jacobson

at the end of https://ceramicartsnetwork.org/wp-content/uploads/2014/12/Glazing_Techniques_Sample.pdf

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18 hours ago, Hulk said:

Hi Mud!

No experience in my own work, nor have I seen any mica sparkle in person ...interesting

https://digitalfire.com/material/1018

Looks like low fire application; see also

     Specialized Techniques

      Mastering Mica

      by Kate and Will Jacobson

at the end of https://ceramicartsnetwork.org/wp-content/uploads/2014/12/Glazing_Techniques_Sample.pdf

Thanks for sharing the sources! I have a feeling I'll be using the glazing techniques pdf quite often now!

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I have fiddled with mica some, using it in sodium silicate stretched/crackle forms, and then a modified very low temperature (cone 018ish) raku-like firing to put in the smoke bin to carbonize the crackles. The issue is that the fun colored mica products are for cosmetics and soap (bath bombs) and they either melt out at hotter than ~1400F or the color burns out. There are a few types of mica used in ceramic bodies that hold their own at the higher temps, but you have to order them specially and they don't have the fun colors.

Edited by Dick White
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On 9/12/2020 at 9:11 PM, glazenerd said:

 

@glazenerd, I was literally just reading that thread! Too bad the pics are so compressed that I can hardly even make out the crystals on those discs!

So the only way to get mica powder you mention is to order it direct from China, is that right? Or are there suppliers in North America?? 

Edit: Okay, scratch that, some ceramic suppliers have mica 325 mesh in stock. This is exciting!

Edited by 2Relaxed
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4 hours ago, 2Relaxed said:

@glazenerd, I was literally just reading that thread! Too bad the pics are so compressed that I can hardly even make out the crystals on those discs!

So the only way to get mica powder you mention is to order it direct from China, is that right? Or are there suppliers in North America?? 

Edit: Okay, scratch that, some ceramic suppliers have mica 325 mesh in stock. This is exciting!

 

IMG_0271.JPG

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  • 3 weeks later...

It's so funny how minds converge on ideas. I began researching mica in glaze before the pandemic and was encouraged by @glazenerd's success. I also wished I could see the pictures better at the time and so thanks very much for so boldly asking. And thank-you @glazenerd for your initial post. The copper glaze is beautiful. I imagine it has high flow?   I was also inspired by cosmic tea dust as I like to use it on my jewelry pieces but I'm not actually convinced they get the effect from mica. I've only seen people theorise on it. 
Now that we can go back to the community studio, I'm going to be trying a smaller particle size of mica that I got off Amazon (mostly just for convenience). Based on the SDSs and CAS #s for mica 325 mesh and the one I got, they should otherwise be the same type of mica. 

Going to try a few different concentrations in our little kiln which I like to use for jewelry and the big kilns which are better for slow cooling.

I'll try to remember to update even if it goes very bad.  

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On 9/17/2020 at 10:58 PM, 2Relaxed said:

@glazenerd Very nice! Do you think micro-crystals are possible with mica? If I omit the hold and/or don't slow cool?

Sorry for the delayed response; family member passed recently and I have been tied up with settling her estate. Microcrystalline glaze form a specific ionic bond called HCP (hexagonal closed pack) crystals. This glaze is mica saturated: and you are seeing the large plate like structure; which is a common property. During the 16-17th century that would quarry large thin sheets of mica for use as window glass. 

Tom

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On 10/6/2020 at 12:45 AM, ChristinaB said:

It's so funny how minds converge on ideas. I began researching mica in glaze before the pandemic and was encouraged by @glazenerd's success. I also wished I could see the pictures better at the time and so thanks very much for so boldly asking. And thank-you @glazenerd for your initial post. The copper glaze is beautiful. I imagine it has high flow?   I was also inspired by cosmic tea dust as I like to use it on my jewelry pieces but I'm not actually convinced they get the effect from mica. I've only seen people theorise on it. 
Now that we can go back to the community studio, I'm going to be trying a smaller particle size of mica that I got off Amazon (mostly just for convenience). Based on the SDSs and CAS #s for mica 325 mesh and the one I got, they should otherwise be the same type of mica. 

Going to try a few different concentrations in our little kiln which I like to use for jewelry and the big kilns which are better for slow cooling.

I'll try to remember to update even if it goes very bad.  

You assumption is correct: the glaze needs to be fluid in order for the mica to form crystals. I use pure muscovite mica: 37% alumina and 13% potassium. (325 mesh)  Enough colorant to suggest color, but not so much as to over power the mica.

Tom

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