SLIP (CERAMICS)

'Slip' in a ceramic context is made by mixing clays and other minerals with water and usually a deflocculant such as sodium silicate. The addition of a defloculant allows the water content to be kept to a minimum which reduces the amount of shrinkage when slipcasting. The mixing can be by hand or more usually in a blunger. Slip can also be used to create a texture similar to that of stucco by smearing the body with slip and then tapping it, causing the slip to form peaks. However, when the slip dries these peaks become very fragile, so they are easily broken off (which can be a good thing, since they can be very sharp after firing).
Slip can be used decoratively when placed onto the leather-dry clay body surface by dipping, painting or splashing, this is often described as slipware. Slip is also used as a sort of glue; two pieces of clay are "scored" (slashed shallowly), slip is applied to both pieces, and then the two pieces of clay are joined. This is almost always necessary when manually attaching pieces such as handles, spouts, and other pieces of clay added to the body.