Medium to high fire highly textured engobe. This natural Kaolin-Sand-Feldspar mix has been used for many years at Plainsman as a body addition to impart texture and improve drying properties. However we have discovered its potential as a textured slip or engobe. Plainsman Clay's ability to mine and process clay without breaking them down into very fine powders is the reason a material like this can exist.
Even though this material contains more than 50% sand and sand-sized clay mineral particles, it has very good application and water suspension properties if it is mixed to a heavy-cream consistency (it has a natural tendency to gel in water). It shrinks much less than other slips during drying and thus is less likely to crack or flake and fall away during drying. It also paints on with less noticeable brush strokes than fine-grained slip and engobes.
Cone 10R (4x Magnification)
The fired textured surface is highly unique and durable. The individual particles are cemented together by the naturally ocurring feldspar in the material. It works best at cone 10 and burns to a durable sandy and very tactile surface. Feldspar or frit can be added to mature it at a lower temperature, however this will grey the color and can cause the development of fired micro-cracks across the surface.
We have tested the integrity of the fired bond between the engobe and body (using a boiling water:ice water immersion test) and have found the bond to be very good.
Sieve Analysis (Tyler mesh):
+48 (300 microns): 0-0.1% 48-65 (300-210 microns): 7.0-13.0 65-100 (210-149): 23.0-30.0 100-150 (149-106): 8.0-12.0 150-200 (106-75): 5.0-10.0 200-325 (75-45): 5.0-9.0
CaO 0.2 K2O 2.9 MgO 0.4 Na2O 0.4 TiO2 0.5 Al2O3 12.4 P2O5 0.0 SiO2 78.8 Fe2O3 0.7 MnO 0.0 LOI 3.7%
Safety Data SheetClick here for web view (format adheres to Globally Harmonized System of Classification and Labelling of Chemicals - GHS)