Specialist Crafts Potters & Casting Plaster

A versatile range of quality plaster can be used to produce working moulds for the slip casting of sanitaryware, tableware or castings. It is off-white in colour and has an approximate initial setting time of 9 minutes. It can be carved, turned, or sanded when completely set and can be painted using acrylic paints once sealed with a primer or PVA glue. The plaster can be stored for up to 6 months providing that it is kept in a dry storage container and the lid is properly secured after use.

Available sizes: 2.5kg Bucket/25kg Bag Potters Plaster and 10kg Casting Plaster.

What's the difference?

Potters Plaster is designed specifically with ceramic mould making in mind. Its porous, absorbent nature helps remove moisture from liquid clay slip, allowing a clay wall to form against the surface of the mould. Preferred choice for slip casting, press moulds, slump moulds, and other pottery techniques requiring repeated use.

Casting Plaster is a more general-purpose plaster designed to create strong, smooth and detailed casts. It is ideal for casting, mould making, sculpture, decorative work and general mould-making projects where the specialist absorbency required for repeated ceramic slip casting is less important. Once fully set, both types can be carved, shaped and sanded. Finished plaster pieces can also be decorated with acrylic paint once suitably sealed with a primer or PVA.

Mixing:

To find the amount of plaster/water mixture needed for your cast, first, fill the mould with clean water and pour it into a mixing bowl. Dry the mould prior to casting. On average ratios are 940g of plaster to 1 pint of water. Slowly pour plaster into the water and stop when the mound of plaster powder starts to show above the water. Mix gently, but quickly, until you have a smooth creamy consistency. Try not to whip/beat the mixture, as this will create air bubbles. The recommended mixing time is approx. 2 to 4 minutes, depending on batch size. The precise consistency to use will need to be adjusted to suit the individual application. Changes to plaster to water ratio will influence product performance particularly setting time, strength and permeability.