Mother Nature's Porcelain, MNP, is a pure mined sedimentary clay called "3B" that is mined in south western Saskatchewan. It fires porcelain density at cone 6 (although not white burning, nature supplies it with just the right amounts of feldspar, silica and kaolin).
MNP is about making your own clay body from the raw lump clay or 42 mesh powder. It is about being “greener” (our traditional porcelains, like P300 and M370 are very carbon-intensive, made from highly processed industrial minerals that are transported from across North America and even over oceans).
A 10kg lump of B clay at the quarry (from the center section of the seam). It is quite damp and amazingly dense and heavy. It is layered, somewhat like the rings on a tree, the lines run horizontally in the clay bed. In the lab its splits apart in layers (revealing carbon stringers of Cretaceous plant life).
MNP has medium plasticity and can thus be used on the potter's wheel as-is. The finer you are able to sieve it the more plastic and smoother it will be. 95% should pass a 200 sieve and 90% a 325. Plasticity can be augmented with a small bentonite addition (e.g. 1-3%).
To process it slurry up the powder, sieve it, and dewater it on the plaster surface until the desired stiffness is achieved. Although it is possible to hand-sieve the material for sizes up to about 80 mesh, a sieve shaker is needed for finer sizes (100-325 mesh). At 100 mesh is practical to make most things, up to 98% should pass the screen. At 80 mesh some fine specks may show through glazes. With a shaker it should be easy to process at 200 mesh.
On the wheel this feels like porcelain - but throws better, it is super plastic but not at all sticky. But unlike porcelains made from commercial minerals, MNP has the drying properties of a stoneware (because of its high dry strength). This balance is only possible when Mother Nature mixes the silica, feldspar and clay!
MNP is the best choice for making dark-colored porcelains, it requires less stain (often much less) to achieve dark colors (e.g. black, brown, blue).
MNP fired test bars from cone 8 (top) to cone 4 (bottom). The bars on the left are the standard 42 mesh pugged material we suppy. The ones on the right we made using a slurry up process, sieved to 325 mesh.
200 mesh MNP fires to zero porosity at cone 6. Add 5-10% feldspar or nepheline syenite if maturity is needed at cone 4-5.
MNP is the best porcelain we have seen for staining to darker colors (e.g. deep blue, black).
MNP with 6% 6666 stain (right) vs. Coffee Clay at cone 5
MNP has enough natural quartz so that almost any glaze that fits our other bodies will fit this.
These are the properties of the 42 mesh material. The finer you screen it the more vitreous it will fire.
Drying Shrinkage: 6.5% Dry Strength: n/a Drying Factor: C120 Dry Density: n/a
Sieve Analysis (Tyler mesh):
+65: ~0.5 65-100: ~2.5 100-150: ~2.0
Cone 4: 6.0 Cone 5: 6.5 Cone 6: 6.5 Cone 7: 6.5
Cone 4: 1.5 Cone 5: 1.0 Cone 6: 0.5 Cone 7: 0
These are Plainsman MNP 100#, MNP and M370 50:50 mix and MNP 80# fired at cone 5 C5DHSC schedule. Inside glaze is L3500G, outside is a 85:15 G2934 and G2926B mix with 6% Mason 6600 black stain added. The pieces have the strength of a porcelain.
MNP with 6% Mason 666 black stain. Clear glazed inside, Ravenscrag blue outside.
MNP 100 mesh with 5% Mason 6666 black stain. Outside is G2934 black, inside is G2926B black. No other body will produce this dark a black with only 5% stain.
The black pixels in this QRCode are made from MNP + 5% Mason 6666 stain.
Safety Data SheetClick here for web view.
|Plainsman Clays Ltd.|
702 Wood Street, Medicine Hat, Alberta T1A 1E9
Phone: 403-527-8535 FAX:403-527-7508