Some metal dental prostheses are cast in a centrifugal casting machine consisting of a mould and ceramic crucible, counterbalanced across an arm by adjustable weights.
When the machine is rotated, molten metal tends to be ejected from the mould, particularly during the first rotations of the arm. Severe burns to technicians sometimes occur while they are doing this work.
In one laboratory the casting machine has been recessed into the laboratory bench so that it is below the bench surface but still easy to reach. As the casting process requires manual operations and repeated applications of heat from a small hand-held torch, a lid over the recess is not practical.
The second safety feature is a hardwood beading or lip around the inside of the opening to the recess. This beading must be wide enough to prevent any metal from splashing or spilling out of the casting mould. (Instead of beading, a lip can be made from angle-section aluminium or steel).
For work with molten metal, suitable eye and facial protection is always necessary. In this case a face shield.
Hierarchy of Controls:
- The risk level of severe or minor burns has been reduced by the fabrication of this simple and inexpensive guard.
- The recess in this case was made from solid chipboard, but it could also be constructed from fibre-reinforced cement sheeting.