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Showing posts with the label specific gravity

Update on Slip Mixing Mystery !

I have been busy attending to many different things and so it took a while to get new materials ordered so that I can test our casting slip using a different water supply. As a reminder ( see last pos t) after mixing slip at our location since 1958, recently I was unable to achieve a functioning balance between specific gravity and viscosity. To put it in easy to understand terms. specific gravity is the measure of the water content of the slip and viscosity is the measure of resistance to fluidity. A low specific gravity means there is a high content of water. A low viscosity means that the mixture is very fluid. I was getting an extremely low specific gravity reading such as I have never seen before and an extremely high viscosity. That is like putting enough liquid into a batter to make it like a soup but instead it is like cookie dough. Neither low specific gravity or high viscosity are functional in a ceramic casting slip. After three different batches of slip were attempted

A "Booming Economy" and the Local Water Supply

Andersen Design has been mixing casting slip at our present location since 1958. I have personally been mixing it for decades but I recently ran up against an unprecedented problem, which has persisted through three batches from three sources, the last being made from fresh raw materials, keeping adjustments for viscosity at a minimum. When mixing clay slip the amount of water content is crucial. Our specific gravity target range is 176-180. The lowest We ever go is 171 and that is for small items only. The viscosity, or fluidity of the slip has to be such that it easily pours in an out of the mold. I do not usually measure that because it is very apparent, The higher the viscosity the thicker the slip and the less flowing qualities it has. If the water content is within range but the viscosity is high, I add a deflocculant and that brings the viscosity down. This is the way it has been working for years until now when we are working on a small but potentially large wholesale or