Plaster Retarder (Trisodium Citrate) is a strong retarder used to control and slow the setting time of your casting plaster. This enables you can mix larger batches, cast larger moulds and volumes and gives you more working time when required. Plaster Retarder is a safe-to-use granular material called Trisodium Citrate, which needs to be dissolved in water and used as a concentrate that is added to the gauging water before mixing in the plaster powder. We recommend 100g of Retarder to 1ltr of hot water and allow to cool before use. This concentrate should then be used to add to your gauging water. As all plasters have different set times, it is difficult to be specific about how much to add and how much it will slow down the plaster. As a guide, we suggest adding 5ml of the dissolved retarder per litre of gauging water, this will slow down the plaster set time by about 5 minutes. Being a very strong concentration only small amounts are needed. We strongly recommended a small test be carried out to ascertain and calculate the needed reactions. Please note; Our Plaster Retarder is designed for use with Casting Plasters, such as Fine Casting Plaster and Prestia Casting Plaster. We have not tested it with building or wall plasters and believe it will not work.
