| Electroforming is a plating process that
requires a very special kind of plating machine; an electroformer. All
plating machines, electroformers included, work on the same general
principle, they use DC current to cause microscopic plates of metal to
adhere to, and build up on, the surface of the piece being plated. The low
amperage and highly filtered current of electroformers produce small, evenly
distributed plates that adhere much better to each other and the underlying
substrate than with standard plating rectifiers. With a standard plating
process, the thickness of the plating is relatively thin ( a few microns at
most) and strong adhesion and even distribution is not critical. With
electroforming, however, the plating is hundreds or thousands of times
thicker. If a standard rectifier were used to produce such a thick coating,
the coating would not only look very uneven, simply rubbing it would cause
the plating to peel off the model. A magnetic stirrer is generally used in
conjunction with an electroformer to insure a very smooth, even coating.
Click hyperlink for
electroforming videos. Electroforming is used to do two very
different things: to build up models to compensate for shrinkage or to make
hollow jewelry from wax models by building up a heavy metal coating on a wax
model. When copying models, it is necessary to compensate for the inevitable
shrinkage that occurs in the various stages of the casting process.
Electroforming is the only known method of doing this. To make hollow
jewelry, the wax is painted with a metallic electrically conductive paint
(usually silver paint) and the electroformer creates a metal coating on top
of the wax. The wax is then heated and drained, leaving a hollow core. For
information on water soluble wax, see Shor Water
Soluble Waxes. For an article on the electroforming process see
Forming a Niche. |