PARTIAL DENTURES – My stone duplicate models are taking longer to set-up in the hydrocolloid. The surface is coming out soft, chalky and lack detail, what is the problem?
Several reasons for stone and oxy-phosphate models to give this appearance; 1. Taking longer for the investment or stone to set-up may be directly related to the water temperature use to chill the hydrocolloid. Water bath should be about 55 degrees Fahrenheit; therefore, the colloid should be at that temperature when pouring the gypsum or oxy-phosphate material. The colder the temperature of the colloid the longer it will take gypsum and investment to set properly. 2. Chalky , soft and smudged surfaces may be due to; a. Insufficient set time b. Colloid temperature too cold c. Improper liquid powder ratios d.
