The cut out pieces from the ceramic vessel are embedding into a block of clay at the leather hard stage. Leather hard is a specific stage where the clay is visibly damp (dark gray in color) but hard enough to work with without damaging the piece. I have made sure that there are no undercuts where the plaster will seep into, preventing the piece from becoming trapped in the mold. I am using cottle boards to block of the diameter of the mold so that when I pour the plaster inside, it will contain its shape. Before pouring plaster in, I have to make sure there are no cracks for the plaster to escape by filling every corner with a little coil of clay. I then apply mold soap to the entire piece, including the cottle boards in order to prevent the plaster from sticking to the piece.
After the kiln cast plaster is poured in, I leave it over night to set up.
The plaster I am using is a very specific plaster used for kiln casting and slumping glass. These molds will be able to withstand the temperature of the glass once it begins slumping in the kiln.
Kiln-fired glass can be done in a ceramic electric kiln between 1300-1500 degrees F, which is lower than ceramic temperatures.
No comments:
Post a Comment