BristolPotter

Yes, I'm buying in the powdered clay from Potclays, it's their 1145. I have been using way more sodium silicate (based on the recipe for casting slip from Potclays themselves), so I suspect that earthenware might behave quite different to stoneware

Hi everyone, I'm new! I currently make a very small range of slipcast items from my own moulds (created using a resin 3d printer, silicone and then plaster) and I would like to be able to use stoneware slip for its plasticity and cost-effectiveness. At present I mix my own porcelain slip that has a S.G. of 1.8, using a dedicated slip mixer, not a hand drill or anything. Every time I try to mix stoneware casting slip in the same way, I can't seem to get it past 1.6 S.G. It ends up over deflocculated if I try. I should mention that I'm in the UK and I can't get Darvan, I use sodium silicate as my deflocculant, with a little soda ash, and then Dispex for fine-tuning viscosity. It all works perfectly well for the porcelain, but the same process does not work for stoneware. Does anyone out there cast in stoneware and make their own slip? I wonder if I'm expecting too high a S.G. from stoneware, or if there's some magic trick that I'm missing to make it behave as well as my porcelain? Thanks for any suggestions!