Slump-Hump & Drape
Slump Molds are concave ceramic forms. Bowls, plates, and platters can easily be made using this technique for it works best for shallow forms. To use slump molds, glass is placed on top of the mold and then heated inside the kiln. While inside the kiln, the glass will soften and slump down into the mold hence the name.
On the other hand, hump molds or drape molds are convex ceramic forms. An advantage that they have over slump molds is it enables you to add feet and handles to the outer surface of the piece. To use hump or drape molds, glass is placed over the mold and drapes over it when heated, which (again) gives it its name.
Both types of molds are made of ceramic because they can be fired in a kiln unlike plaster molds. They can be used with any piece of glass (sheets, noodles, frits, etc.) for both COE 90 and 96 (remember though that you CANNOT mix both COEs together).