Blue Grey Plastic

Alternate Names: 98 Blue Grey Plastic, 98 BGP

Description: Highly plastic red burning earthenware

Oxide	Analysis	Formula
Al2O3	15.35%	1.44
SiO2	66.90%	10.63
Fe2O3	3.72%	0.22
CaO	0.49%	0.08
K2O	3.25%	0.33
MgO	1.58%	0.37
Na2O	1.33%	0.20
Cr2O3	0.01%	-
MnO	0.02%	-
P2O5	0.11%	0.01
SrO	0.01%	-
TiO2	0.50%	0.06
LOI	6.80%	n/a
Oxide Weight		890.28
Formula Weight		955.24

Notes

An extremely plastic red burning fine-grained material from the Elkwater area in southern Alberta. It was used in brick manufacture and in pottery clay bodies and it was still in use in the production of Alberta Slip in 2024. This was a successor to 45R.

Ba ppm: 1006
Cr ppm: 39
Ni ppm: 34
SO₃: 0.04
Sr ppm: 66
V ppm: 78

Loring Labs analysis 2006 showed 16.2 Al₂O₃, 64.0 SiO₂, 4.6 LOI, 4.55 FeO₃, 2.7 SO₃.

Related Information

Redart fired bars vs. Plainsman Blue Grey Plastic

The Redart clay bars (left) are fired at cones 06, 04, 2, 4 & 5 (top to bottom). The Plainsman Blue Grey Plastic bars (right) are fired at 06, 04, 03, 02, 2 & 4. The SHAB test procedure (used to make these) gives us the firing shrinkage and porosity at each temperature, these are direct indicators of the fired maturity. Notice how much the fired color changes with increasing temperature. The fired maturity is pretty similar but the BGP is a little browner in color. It is also much more plastic (the drying shrinkage quite a bit higher).

Links

Typecodes	Clay Other Clays that are not kaolins, ball clays or bentonites. For example, stoneware clays are mixtures of all of the above plus quartz, feldspar, mica and other minerals. There are also many clays that have high plasticity like bentonite but are much different mineralogically.
Materials	98 Mix

By Tony Hansen
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