High temperature, smooth, medium plastic, vitreous, white firing, refined body for reduction and oxidation porcelain functional ware. P600 is intended to provide the most porcelainous nature possible in a plastic vitreous cone 10 white body made from North American kaolins (#6 Tile and EPK). It is fluxed with nepheline syenite and has 23% silica and we add some micro-fine bentonite to increase plasticity. It is a legacy product, P700 is has better firing and working properties.
P600 is a smooth and very slick fine grained body. Its kaolin-only nature impart a different plastic character than white stonewares (which also contain ball clay). P600 is plastic, but not as plastic as P700 or H570.
P600 demands more than the usual attention during drying, especially on difficult shapes (like large flat plates). Time is required to remove all the water since the bentonite and #6 Tile kaolin resist water penetration. If you need to join sections, be sure to follow good practice (i.e. use as much pressure and lateral movement as possible when joining, dry pieces evenly, avoid making ware with an uneven cross section.
P600 fired bars. Cone 10R top. Cone 6 to 11 oxidation (upward from bottom).
Although P600 is not a true translucent porcelain, it does vitrify to a very pleasant silky surface and does display a measure of translucency on thin pieces. It is not nearly as white as P700. P600 normally reaches zero absorption at cone 10 and 10R. If ware made from it has a shape that is not structurally strong (i.e. a straight sided cylinder, goblets with flared bases, overhung bowls) it is likely to warp, especially if set on kiln shelves that are not flat.
P600 has a more pleasant vitreous surface than H570 and fires whiter but it is more prone to warping during firing. P700, on the other hand, is whiter than P600 and even more vitreous.
P600 is a variation on the widely used '25% Porcelain' recipe. However it uses only kaolin rather than a kaolin:ball clay mix. It thus has a lower silica content and so crazing may occur if your glaze has a high thermal expansion.
The body fires to a high strength, a strength that can be severely compromised if a glaze is under excessive tension. We recommend that you stress-test a piece of ware using a boiling water:ice water test. Ware should be able to survive several two-minute cycles before trouble appears. If you need assistance to adjust the thermal expansion of your glazes, please call Plainsman.
If you wish to use slip on your ware, make it from a base of P600 for the best possible drying shrinkage/fired shrinkage match.
You can develop a compatible glossy or matte base for this body from our suggested starting point base recipes available on our web site. Information is given on how to fit the glaze to your body and how to customize it it for colors, opacity, speck, variegation, etc. For slip decoration, be careful to match drying and fired shrinkage of the slip with the body since low temperatures generate little glass to adhere the slip.
We do not supply a thermal expansion value. The reason is that such numbers often mislead users. First, a body has different thermal expansion characteristics when fired at different temperatures, schedules and atmospheres. Dilatometers are only useful when manufacturers can measure bodies and glazes over time and in the same firing conditions. If a chart is supplied here, please view only as a way to compare one body with another.
Another significant issue is that many customers compare measured thermal expansion numbers with calculated values of glazes in efforts to fits those glazes to a body. This does not work. Calculated values are relative only and have limitations that must be understood. The best way to fit glazes to your clay bodies is by testing, evaluation, adjustment and retesting. For example, if a glaze crazes, adjust its recipe to bring the expansion down (using your account at insight-live), fire a glazed piece and thermal stress it (300F into ice-water). If it still crazes, repeat the process.
If we recommend a base clear or glossy glaze, try calculating the expansion of that as a rough guide to know whether your glazes will fit.
Thermal Expansion Chart. Average: 5.5.
Drying Shrinkage: 5.0-6.0% Dry Strength: n/a Water Content: 22.0-23.0% Drying Factor: C110-C120 Dry Density: n/a
Sieve Analysis (Tyler mesh):
+100: 0.0-0.1% 100-150: 0.1-0.3 150-200: 0.2-0.8 200-325: 3.0-5.0
Cone 8: 7.0-8.0% Cone 10: 7.0-8.0 Cone 10R: 7.5-8.5
Cone 8: 1.0-2.0% Cone 10: 0.0-0.5 Cone 10R: 0.0
P600 Salt Fired by Jim Etzkorn.
Safety Data SheetClick here for web view.
|Plainsman Clays Ltd.|
702 Wood Street, Medicine Hat, Alberta T1A 1E9
Phone: 403-527-8535 FAX:403-527-7508