Superior White Porcelain Technical Specifications
Description
A snow white translucent very plastic porcelain for throwing, hand
building, RAM pressing and casting.
Mesh : Ball milled body
Recommended Firing
Bisque
Glaze
|
1060° C |
1280° C to 1300° C |
|
Orton Cone 04
at 150° C per hour |
Orton Cone 9 to 10
at 150° C per hour |
Coefficient of Expansion
Sample fired at 1285° C, Orton cone 9. Linear expansion is
0.350% at 500° C and coefficient is 75 x 10-7 from 200° C to 500° C.
|
Analysis
|
Shrinkage
(fired)
|
|
SiO2 |
75.02% |
From wet to dry |
2.3% |
± 0.5% |
|
Al2O3 |
20.30% |
From dry to bisque |
0.2% |
± 0.2% |
|
TiO2 |
0.40% |
From bisque to glaze |
10.0% |
± 0.5% at 1280° C Orton Cone 9 |
|
Fe2O3 |
0.40% |
|
CaO |
0.19% |
|
MgO |
0.70% |
Water absorption |
|
Na2O |
1.15% |
Biscuit |
1000° C |
Orton Cone 06 |
16% |
|
K2O |
1.83% |
Fired |
1220° C |
Orton Cone 6 |
less than 2% |
|
L.O.I. |
6.20% |
Fired |
1250° C |
Orton Cone 7 |
0% |
Presentation
Fully de-aired 10 kilogram block wrapped in recyclable
polythene bags.
Moisture content of standard clay is 22% to 24%, PR 3 to 4.
Other moisture contents are available on special request using
our Penetrometer Readings (PR) outlined below.
|
PR |
Consistency |
|
2 to 3 |
Soft |
|
3 to 4 |
Ideal throwing |
|
5 to 6 |
Firm throwing, slab work |
|
7 to 10 |
Slab, pressing or extruding |
Preparation
Crude clays are blunged, sieved and passed over rare earth
magnets, then stored in constantly agitated farm tanks. Final body blend is made
with millimetre accuracy with powdered raw materials being added and agitated
in. With this manufacturing method we can ensure reproducible recipe formulation
to within 0.1%. Final body in liquid form is sieved and passed over rare earth
magnets once again and then filter pressed. Filter pressed clays are then stock
piled in cake form and allowed to age. Extruding takes place through a de-airing
pugmill and clay is sealed airtight in polythene bags which can be stored
indefinitely.
Potter's Comments
Joseph Szirer, Senior Lecturer in Ceramics, Monash University,
Melbourne
"A smooth, white and robust body. Excellent to throw or
hand building of small to medium pieces. Easy to join and a pleasure to turn.
All in all an outstanding body."
"For years we have been looking for
a super white porcelain body (not grey, not beige). Finally we have it in Walker
Ceramics' Superior White Porcelain. Its intense whiteness means much richer
colour response. Its fine texture gives a glossier glaze result. Its fired
durability survives the most destructive of commercial kitchens. It is a
versatile clay that can be pressed, thrown or hand moulded."
Virginia Maywald & Tim Dolan of The
Big Duck & Fish Company
