search  current discussion  categories  materials - misc 

mica in clay

updated sat 21 jul 01

 

Ron Collins on thu 19 jul 01


I do a lot with mica mixed in a hand dug earthenware body, with =
additions. JUST WEDGE IT IN......I hand roll a thick coil, flatten it =
out with a groove in the center, spray on water, and dump in =
mica...repeat, and repeat...until you've got your 50% (by volume) =
in...We know where a whole mountain of mica is...don't assume you will =
find enough in the clay that you dig. ...I add about 50 percent by =
volume hand=3Dground mica done in a corn grinder..this may sound kinda =
back-woods, but you don't need tons of the stuff anyway, so just find a =
way to grind it down to about 1/8 inch or less, you'll have all sizes of =
particles.......my clay's not that short, the mica makes a nice greasy =
feel to the clay...the properties are real...it will fire on ANY type of =
stove top wood, gas, or even electricity. YES.........when fired at 06 =
or below, it does look like gold....even if you don't want micaceous =
clay, just the look, grind the mica and sprinkle on top of the slab =
before cutting and roll in.......I use white, terra cotta and darker =
natural slips, roll out slab, sprinkle on mica, roll in mica then cut =
and make...it's beautiful...vermiculite won't do all this...micaceous =
clay doesn't shrink much at all...making additions of glass, metal, etc =
easy to work with and fire into the clay...It's tough, and I want to do =
a paper kiln firing on raw ware just to see what it will do...but you =
can exploit the physical properties and have something gorgeous....It's =
got all sorts of great properties if you have a source, and the =
indigenous don't have proprietary control over what I put in my =
clay...Melinda Collins in Guatemala

Phyllis Tilton on fri 20 jul 01


Melinda: How large are the particles of mica that you use? Or is there a way that it is reduced in size or does it come powdery? At a pit firing workshop that I attended, the instructor had a fine-almost powdery-mica. We wedged it into the red clay. After reading your post, I wish I had used more. Now I want to try again. In using the 50%, does it look more golden? I am intrigued!

Thanks!

Phyllis Tilton

Daisypet1@yahoo.com

Daisypet@aol.com



---------------------------------
Do You Yahoo!?
Get personalized email addresses from Yahoo! Mail - only $35 a year!
http://personal.mail.yahoo.com/

Ron Collins on fri 20 jul 01


Phyllis...the mica that I use, I gather off the ground and use a pick to get
chunks out of the side of the hill....it has sand in it, and a little clay
probably, and when you grind it, it will be all sizes, from powdery to large
flakes. I only window-screen it to get out any rocks,etc, but there's never
anything much of that. From what I hear, the NM suppliers sell mica that is
200-300 mesh, and that's too fine to really stand out and show off if you
want the sparkley look--bear in mind that when you use more coarse mica, and
add a lot, the piece can get very light, like paperclay, and too much and
it's brittle and easily broken....so do some tests, and find the happy
medium....as with all prospected materials, my source will be different from
yours in terms of what's in it, and how it works. Melinda Collins, Antigua
Guatemala