Fine casting plaster – excellent texture and detail from almost any surface
Ratio for mixing fine casting plaster is 1kg plaster to 700ml water. If too much plaster is added the plaster will not be absorbent enough: not enough plaster will result in soft, crumbly set which may contaminate your clay. Measure the correct amount of cold water out into a clean, flexible container. Sprinkle the plaster evenly over the surface of the water a handful at a time. The plaster should form peaks above the water surface towards the end of this process. When all the plaster has been added, place your hand in the mixture so that your wrist is a few inches below the surface and your hand is at a right angle to your forearm. Mix the plaster without allowing your hand to break the surface. This is to prevent air bubbles being introduced to the mixture. Keep mixing until the plaster seems to thicken slightly. It is now becoming ready to use. You only have around 2-3 minutes to work, so try not to make up more plaster than you need. After you have made your mould, wait until waste plaster has set and then flex the container to break it cleanly away. Plaster must never be washed down a sink as it will block it, so wait until the plaster on your hands has dried and then place all waste plaster in a bin.