The process of slaking clay to make it into slip is a simple one. Step one is to have a 5-gallon bucket filled 60-75% with your bone-dry clay then add water until it’s a few inches below the rim (figure 1). Let it slake for 24 hours then mix it by hand a little with a stick (figure 2).
How do you make a slip for casting molds?
What is casting slip made of?
The molds used for slip casting are usually made of plaster. They are formed by mixing gypsum and water in a 4:3 ratio and allowing it to harden around a replica of the shape you hope to produce.
What is the ratio of clay to water in slip?
This is a ratio, it is generally accepted that 1.75 is good for slip casting. So our slip is a little light at 14.4 lb. per gallon, water weighs less than clay so we have too much water in our slip, we can’t take it out so we have to add more dry materials. (if the slip was too heavy we could have added water.)