How Enamel Dials are Made
7 November 2006One of the most interesting facets of Horology has to be the hand made works of art found in enamel pocket watch dials. These came into fashion with 19th century pocket watches but were introduced many years before in clock dials. In fact, the technique of enameling dates back to ancient China.
The main benefit of enamel dials is that they are impervious to the elements. The enameling is resistant to water stains, ultra violet light, and dust, each environmental _condition which can age and degrade painted dials, yet can give us the attractive dial patinas from aging that are so desirable. With the exception of cracking and chipping, enamel pocket watch dials seem never to age, and are as beautiful today as when first produced.
The technique involves producing the dial blank out of a thin sheet of copper. These can be either stamped out or hand crafted. The sheet is usually hammered into a slightly convex shape, then a hole is drilled in the center large enough to allow for the axis of the hands.The dial feet are now soldered on the copper blank. The feet are usually made of copper or silver wire. A thin brass band is constructed around the circumference of the blank and the hands hole allowing for the enamel to melt flat and stay confined to the surface of the dial.
The enamel is a fine white opaque glass ground into a powder the consistency of fine sand. The enamel is then spread very evenly over the entire surface of the copper blank. Most high quality enamel dials have the dial feet side also enameled. This assures that the copper blank will not be altered by the unequal shrinking of the metal and enamel when the dial is heated and then cooled.
The dial is placed in an Enameler’s Furnace and heated until the enamel particles melt together, forming a glossy glaze with uniform consistency. The heating temperature to achieve this process is approximately 840 degrees Fahrenheit. The dial is removed from the furnace and allowed to cool. A second coating of enamel is fired onto the first, usually of a finer powder. Now the dial is ready for the numbers, figures,division marks, etc., which are usually made of black enamel, though any contrasting color will work. The enamel used for the markings is ground into the finest powder and mixed with oil, then painted on with an extremely fine paintbrush and fired again. The black enamel melts at a lower temperature than the underlying white, so the base stays stable during this final firing.
Below: A very rare example of a decorative dial from the turn of the century. Waltham 18 size movement.
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