Textured Engobe

Description

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.

Process Properties

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.

Firing


Cone 6 Ox

Cone 10R

Cone 10 Ox

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.

Physical Properties

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

Chemical Analysis

 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 Sheet

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Logo Plainsman Clays Ltd.
702 Wood Street, Medicine Hat, Alberta T1A 1E9
Phone: 403-527-8535 FAX:403-527-7508
Email: plainsman@telus.net