Potters Plaster
Potters Plaster is a mould-making material for slip casting sanitaryware, tableware, and castings. It cures in 9 minutes, has an off-white color, and can be carved, turned, or sanded once fully set. For painting, a primer or PVA glue sealant is required. The product can remain viable for 6 months when stored in a dry, sealed container.
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.