3D Silty Clay

Medium to high temperature, silty, low plasticity, light tan firing, clean native stoneware. It is mined from our Ravenscrag, Sask. quarry. We have unlimited reserves of it.

3D is a high-quality body ingredient. It contains natural feldspar and quartz (so bodies based on it need no silica or feldspar). It vitrifies fully by cone 10. A 2% talc addition will vitrify it at cone 6! Mechanically, it is the cleanest (lowest in particulates and oxides of iron) and most consistent raw material we have. In the raw lump form, 3D clay weathers and slakes very readily. It is suitable as a filler where the other ingredients produce too much plasticity. It is suitable as a body base, the majority ingredient. It's low drying shrinkage (yet high dry strength) give it excellent potential in industrial applications.

3D stockpile at the Plainsman plant site

95% 3D and 5% bentonite produces a body with good plastic workability that fires very pinhole and glaze-defect-free. By itself, it dust-presses well (for tile manufacture). It works well with additions of low temperature iron-bearing clays (like Redart) and responds well to small feldspar and talc additions to achieve maturity from cone 5-10.

3D is also a alternative to sand or grog as an addition to bodies where plasticity needs to be cut and drying properties improved (without compromising vitrification).

3D opens up the internal pore structure in the dry body matrix, this helps channel water out during drying.

3D fired test bars from cone 10 down to 5 oxidation and cone 10 reduction (top).

3D, by itself, vitrifies to 0.5% porosity at cone 10. In oxidation it burns buff, increasing to grey-buff as temperature increases to cone 10. It fires with less reduction speckle and to a lighter buff color than any other native naturally-fluxed material we have.

Because 3D is low in gas-producing particles, glazes fire with fewer surface defects (e.g. pinholes, blisters). In fact, even the unground, slaked material produces clean glaze surfaces. Minimal processing is needed to make the lump form useful.

This material is good base for medium and high temperature body recipes. It can be the majority ingredient because it contains natural feldspar and quartz, so it only needs a plastic clay addition. For medium temperature, only a little feldspar or talc is needed. If it is processed to a finer particle size (by air separation or wet sieving) plasticity increases significantly (to the point that it can be used 100% to produce a cone 8 stoneware).

To see some example bodies that demonstrate the amazing possibilities of this material, plus more technical information, please click here.

 Drying Shrinkage: 4.5-5.5%
 Drying Factor: B110

Sieve Analysis (Tyler mesh):

     +48     (300 microns): 0.0-0.6%
   48-65 (300-210 microns): 0.5-1.0
  65-100 (210-149 microns): 0.5-1.5
 100-150 (149-106 microns): 1.0-2.5
 150-200  (106-75 microns): 3.5-5.5
 200-325   (75-45 microns): 5.0-8.0

Fired Shrinkage:

   Cone 6: 5.5-6.5%
   Cone 8: 5.5-6.5
  Cone 10: 6.5-7.5
 Cone 10R: 6.5-7.5

Fired Absorption:

   Cone 6: 3.5-4.5%
   Cone 8: 2.0-3.0
  Cone 10: 0.3-0.9
 Cone 10R: 0.2-0.7

 BaO       0.4
 CaO       0.2
 K2O       2.6
 MgO       0.5
 Na2O      0.1
 TiO2      0.6
 Al2O3    16.3
 P2O5      0.0
 SiO2     71.5
 Fe2O3     1.1
 MnO       0.0
 LOI       6.6%