I drink from these when I dream

For many years, I have processed the clay for these myself, from lumps I get from the raw stockpiles behind the Plainsman plant. These are made from the PR3D raw clay mined near Ravenscrag, Sask. It is the bottom layer of six. It has the most potential for pottery because it is low in contaminants, fine-grained, light-burning and vitrifies well below cone 10. When I remove all particles coarser than 200 mesh (by slurry up and vibratory sieving) this becomes MNS (mother nature's stoneware) all by itself. Left: 200 mesh. Right 325 mesh. Centre: 150 mesh with added ball clay and feldspar to produce porcelain.

My coffee tastes better in these because they symbolize the potential of even the current quarry (as opposed to importing tens of thousands of bags of American clays each year). This is what I dream about. Processing the products past 42 mesh to get porcelain-like bodies. The finer particle size doesn't just unlock plasticity, but it eliminates problems that plague customers: glaze pinholing, fired specks, coarse particles and sand, even inconsistency and poor drying. Couple that with moving to a deposit further east and reduce soluble salts are reduced and clays get whiter. I even dream that this clay won’t get left in the ground, unmined, like what’s been done for the past three minings! Even that these glazes will be made. Is the future under our feet or in Tennessee and Georgia?

Related Pictures

Here is What Processing a Clay Can Do

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The clay is Plainsman 3B.
Left: Without processing, other than grinding to 42 mesh (currently the finest Plainsman can grind on a practical scale). When fired toward zero porosity it burns like this (at cone 6, 8, 9, 10 and 10R bottom to top). Of course, these are not big issues for non-vitreous rustic bodies fired at cone 6. The speckle and bloating are caused by impurity iron-bearing particles and others having an LOI (they decompose and produce gases that cause the bloats).
Right: The impurity particles make up a small percentage; they can be removed in the lab by sieving to produce a natural porcelain that fully vitrifies by cone 6 (the middle bar). Only about 5% of the material was removed to produce this amazing product (I call it MNP).
Imagine what could be done if this raw material could be mined further east, where clay quality is much better!

Here is why new grinding equipment is needed

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These two pieces have been fired to cone 6, without glaze, I use this as a way of comparing changes in the character of the fired surface over time. These are made from a mix of A3 and 3B, the two main raw stoneware clays. The mix has been ground to 42 mesh (using a hammer mill). These materials vary in the amount of sand they contain and the amount of iron stone concretion particulates, so smoother and more speckle-free than this as a matter of normal variation. Plainsman has made sandy and speckled clays like this for so long that they seem normal. Yes, rustic bodies do have their appeal. However, the limits of the particle size reduction equipment and current quarry materials have resulted in importing American materials to satisfy customers who want smoother, whiter, more plastic and more vitreous bodies. Plainsman is now producing tens of thousands of boxes a year made from these imported materials! Transporting expensive clays at great distances begs the question of why not better leverage the clay resources that are right here. That, and associated independence, quality and lower production costs, are hopefully coming soon.

Rutile Blues - Almost every single stoneware potter uses them

These are made from Canadian materials and recipes

Rutile blue glazes - essential to every potter

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There is a lot of magic, Canadian magic, in this picture. Pretty well every single potter working at mid-temperature needs rutile blue, gloss black, honey amber and transparent glazes (even multiple versions of each). And almost all need a base slip (or engobe). Here they are.

Upper left: GA6-C and GA6-B on light and dark burning bodies.
Upper right: GR6-M and GA6-C on M340 (with black engobe L3954B).
Lower left: GA6-C and GA6-B on M340 (with black engobe).
Lower right: GR6-M, G3914A, G2926BL on slow and fast cooled mugs.

Every glaze company makes multiple variations of each of these, especially rutile blues (or floating blues). Unfortunately, they often do not fit Plainsman Clays. But these do, in fact, they are adjustable (and better in other ways, as well as less expensive). Unfortunately, even though Plainsman Clays mines and makes most of the raw materials and gives out these recipes, it has not been making them, forcing customers to use the American-made products. This is a missed opportunity, hopefully rectified soon.

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