Drop Ring Mold
Click here to go
to a tip that discusses drop ring basics.
While it is possible to construct a drop
ring using ceramic clay techniques such as slab rolling and slip
casting, a simpler approach involves simply cutting a hole in
refractory material. By varying the shape and size of the
hole, the mold can be used to make products ranging from simple
bowls to soap dishes to ashtrays and more.
Making a drop ring mold involves three
steps: selecting the refractory material, shaping the
material to make the mold, and preparing the mold for firing.
Selecting the Refractory Material
Fiber board, such as Unifrax’s Duraboard,
is the most commonly used product, but many other refractory
materials can be used. The key requirements are that the
material be at least one half inch thick (one inch or more for
larger and thicker items such as sinks), that it be able to
withstand prolonged firings at 1300F/700C, and that it can be
Examples of other materials that work
well are Ceramaguard (a ceiling tile made by Armstrong),
vermiculite board (Skamol is one common brand), and block
insulation (such as TR-19 by Thermal Ceramics). Many of these
alternative products have the advantage that they are less
hazardous and less expensive than traditional fiber board.
Click here for the
second part of this tip, which involves shaping the refractory
material to make the mold.
Copyright 2006 Brad Walker. All rights
Parts of this discussion
have been previously published in Glass Craftsman