Can someone test my clay?

On Sat, 15 May 2004 21:56:33 -0400, knob wrote:


I'm about 1.2 hours Southeast of you in the heart of the
Northwest Ohio Black Swamp. Ancient lakebed, flat as
you can get. I am on a rocky ridge though. I dug about
4 feet down, how deep do you dig?

I only have to dig a couple of feet or less to hit clay in my garden,
but since this is a subdivision, that depth is undoubtedly in
the region that has been disturbed by the developer's
original contouring.

Michigan has been extensively modified by glaciers, so I have
no idea if there are any primary deposits around... but I seriously
doubt it.

Your rocky ridge might be a source of granite from which primary
clay could erode. The question is where it would go after erosion.
Most of the time, it is swept along and tumbled by stream action,
and ends up as secondary clay somewhere else. I suspect that
you need some sort of "settling basin" right below the ridge in
order to have the primary clay end up there.


Bob Masta
dqatechATdaqartaDOTcom

D A Q A R T A
Data AcQuisition And Real-Time Analysis
www.daqarta.com

On Fri, 14 May 2004 12:38:42 GMT, (Bob Masta)
wrote:

SNIP

But it would be interesting to know how commonly
one can expect to find stoneware clays in the wild.
I think these need to be "primary" clays, weathered
out of a granite cliff right into a local deposit. So I
suspect there need to be mountains around...
something we don't have where I live (Ann Arbor,
Michigan), but obviously not everyone is so
handicapped. ;-)

Oops, my mistake! It seems only kaolin and
similar porcelain clays are primary types, and
everything else is secondary, washed to its
present location by water. In fact, my garden
clay is not mature at cone 2, but melted by
cone 6, so it's somewhere between low-fire
earthenware and high-fire stoneware. I don't
know how to tell other than by testing.

Sorry for the confusion...


Bob Masta
dqatechATdaqartaDOTcom

D A Q A R T A
Data AcQuisition And Real-Time Analysis
www.daqarta.com

I found a marvellous site for researching raw clay. It gives all the
information you need. www.covenantacres.com. After reading it, my
admiration for clay suppliers increased tenfold as the work involved was too
much for me.
"Uncle John" wrote in message
...
want to learn more based on a memory from their crazy dad.
Maybe not. I've got my eye on a pile of bricks for my
kiln already.

Go to the library and request Michael Cardews book "Pioneer Pottery". It
should answer most of the questions for you.

John W