glazenerd Posted July 21, 2016 Report Share Posted July 21, 2016 For those wanting to explore an alternate to crystalline glaze without the hassle and headaches: how about Mica Crystals. A simple variation to the standard crystalline formula fired to cone 6: with a slow cool from 2100 to 1900F @ 200F an hour. Option: or do a ramp hold at 2025F for two hours. The formula was set to a median of the top three formula limits, and loosely based on a crystalline glaze recipe: Frit 3195 50% Zinc 5% Mica 20% Silica 25% Rutile 2% * seeding agent) shown- 0.25% copper carb. Swap out zinc for frit or silica pending use. Mica is also an excellent substitute for G-200 in porcelain clay bodies. G-200 typically runs 10% +/- of potassium, and Mica typically runs 12% +/- of potassium. There are no known deviations in flux levels for mica as seen with other feldspars. There are however three primary grades of Mica: the potassium does not change, but the iron, magnesium, and titanium do. Mica produces a white body porcelain. Nerd Link to comment Share on other sites More sharing options...
Magnolia Mud Research Posted July 21, 2016 Report Share Posted July 21, 2016 Who are the suppliers? and what is the particle size distribution? LT Link to comment Share on other sites More sharing options...
glazenerd Posted July 21, 2016 Author Report Share Posted July 21, 2016 Yippin 2200 Mica- 325m. Tech sheet is out in the studio: all I remember sitting here. The supplier is not a traditional source for the clay arts, and sell in bulk. Not sure forum rules allow me to disclose that- moderators? Nerd Link to comment Share on other sites More sharing options...
Joseph Fireborn Posted July 21, 2016 Report Share Posted July 21, 2016 Nice crystals. Link to comment Share on other sites More sharing options...
terrim8 Posted July 21, 2016 Report Share Posted July 21, 2016 You mean actual muscovite? I thought it might just be a name for a muscovite rich mixture. Here is a good place to get some mica & grind your own! Nor sure if they let you take "samples". http://giantcrystals.strahlen.org/america/etta.htm The spodumene is useful too but my back hurts from gardening, let alone hauling one of these crystals home. Link to comment Share on other sites More sharing options...
mss Posted July 21, 2016 Report Share Posted July 21, 2016 You don't want to breathe mica. Acute Health EffectsIn some people, mica can have the immediate effect of irritating the eyes and skin, causing redness and itching. Inhaling mica can cause wheezing, coughing and shortness of breath as it irritates the mucous membranes lining the lungs. For contact with the eyes or skin, the area should be flushed with clean water for at least 15 minutes. In cases of inhalation causing acute symptoms, the person should be moved to a space with fresh air and given oxygen if breathing is difficult.Chronic Health EffectsRepeated high exposure to mica can cause fibrosis in the lungs, where the constant irritation from inhaling mica dust causes scarring of the lung tissue. This results in the chronic coughing and shortness of breath typical of pneumoconiosis, a disease often seen in people who work in mines where they are exposed to coal dust. The carcinogenic effects of mica are unclear, but considering other known health effects it is probably best to avoid exposure as much as possible.Avoiding Exposure to MicaWearing protective clothing, gloves, goggles and face masks when working with mica is the best way to avoid skin contact and inhalation. Protective gear should not be taken home; instead it should be washed on site every day. Using engineering controls such as isolation and proper ventilation of work sites is also essential for reducing exposure. Mica is considered a hazardous substance, and work sites that do not enforce the legal exposure limits should be reported to OSHA as unsafe. from http://www.ehow.com/info_8551607_harmful-effects-powdered-mica.html Link to comment Share on other sites More sharing options...
Rae Reich Posted July 21, 2016 Report Share Posted July 21, 2016 Beautiful result at ^6. How big is your sample with the ID tile beside it? Link to comment Share on other sites More sharing options...
glazenerd Posted July 21, 2016 Author Report Share Posted July 21, 2016 You don't want to breathe mica. Agreed, but that holds true for most of the products we use in this trade. Rae: the tile is a 6" disc. The clay test bar was formulated using mica, shown for alternate flux uses. Nerd Link to comment Share on other sites More sharing options...
Marcia Selsor Posted July 21, 2016 Report Share Posted July 21, 2016 Why is it crawling? Great color and nice crystals. Marcia Link to comment Share on other sites More sharing options...
bciskepottery Posted July 21, 2016 Report Share Posted July 21, 2016 Yippin 2200 Mica- 325m. Tech sheet is out in the studio: all I remember sitting here. The supplier is not a traditional source for the clay arts, and sell in bulk. Not sure forum rules allow me to disclose that- moderators? Nerd Sourcing an item as part of a response is okay. Hawking a product . . . not so. Link to comment Share on other sites More sharing options...
glazenerd Posted July 22, 2016 Author Report Share Posted July 22, 2016 Why is it crawling? The piece is perfectly smooth, no crawling. You are seeing "whitish" patches that are clusters of mica without crystal formation. Nerd Link to comment Share on other sites More sharing options...
Denice Posted July 22, 2016 Report Share Posted July 22, 2016 Very cool. Denice Link to comment Share on other sites More sharing options...
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