Dials and Hands
The white, or sometimes black, dials of pocket watches and early wristwatches were made by firing vitreous enamel at high temperature onto a thin copper plate.
Vitreous enamel is made from powdered glass. This was fused onto the copper dial plate by firing at high temperature, melting the glass and causing it to run together to produce a smooth glassy surface. First the white or black background is made, which might take four rounds of firing and smoothing to get the desired finish. Then the numbers and tracks are drawn on in black or white "painting enamel", which is fired at a lower temperature to fix it to the white background.
After firing an enamel dial is invulnerable to ageing or fading. Vitreous enamel dials will be cracked if they are flexed by being clumsily removed from the movement, but apart from this they will last forever.
Sometimes these dials are described as "porcelain", but porcelain is a ceramic made from clay that is used to make sinks and toilets. It is totally unsuitable for making watch dials. Vitreous enamel is called "porcelain enamel" in the USA, which often gets shortened to "porcelain". In any language this is completely wrong.
Dial cross section
The cross section here shows how an enamel dial is made. A sheet of copper is cut to the correct size and shape, with holes cut for the hand arbors and dial feet attached to its underside. The dial feet are small copper rods soldered to the underside of the dial that enter holes in the movement bottom plate and are held in place by screws, holding the dial to the movement.
The copper dial plate was coated with vitreous enamel, crushed and finely powdered glass. It was then heated in a furnace until the enamel melted, fusing together to form a smooth surface and bonding to the copper.
The numerals and minute and seconds tracks were then either painted or stamped on in vitreous painting enamel, sometimes called vitreous ink, and the dial fired again. This melted the enamel of the numbers and other details and bonded them to the base layer of enamel. In the cross section I have shown a white enamel dial with a red 12. When the enamel of the numbers and other details melted and bonded with the underlying enamel it became virtually flat with the dial surface as the cross section shows.
Initially the numbers and tracks were painted by hand, but later an engraved copper block was used. The engravings were filled with vitreous ink and a gelatine pad used to pick up the ink and stamp it onto the dial. In this way many dials could be made accurately and quickly.
Names on the dial
Throughout the nineteenth and early twentieth centuries British retailers only allowed their own names onto the dial. The concept of a "brand" being applied to watches was unknown, and the names of foreign manufacturers were simply not allowed. This only changed in the mid 1920s when Hans Wilsdorf started to advertise the Rolex brand in Britain and people started asking for Rolex watches. Wilsdorf says that when the Rolex Oyster was launched in 1927 he made the decision that he would insist that all Rolex watches carried the brand name on the dial. This was the start of a trend and other manufacturers soon followed.
This generally meant that watches supplied to the British market before the late 1920s or 1930 had dials with no name on them at all, they were left blank so that the retailer's name could be painted on in enamel paint. The importer might have offered this as part of his service to the retailer, or the retailer may have arranged himself for his name to be painted onto the dial.
Enamel paint is quite different from vitreous enamel and nothing like as durable. It is a solvent based paint applied cold with a brush. Often a retailer's name painted on to a dial in enamel paint has partly or almost completely worn away or flaked off over the years, whereas the rest of dial markings in fired vitreous enamel are still crisp and sharp. This is an easy indication that the name was painted on after the watch was made.
When you have looked at a lot of original watches without brands on the dial, seeing a manufacturer's name or brand on the dial looks wrong and not original. However these days people like to see a brand name so sometimes well known names are added to the dials of watches in an attempt to boost their value. A name painted on recently using enamel paint can be difficult to identify, it looks crisp and sharp and glossy, just like the rest of the dial. There are two ways in which such an addition can be identified.
- Look carefully across the dial at an oblique angle with a lens in good light. As the cross section shows, enamel paint usually stands up proud of the surface unlike the fired enamel numbers which are virtually flat. If you can see the name standing up like this it has definitely been added, but a very skilful painter will make the letters very flat so some painted names can evade detection by this method.
- Wipe the suspect lettering with a solvent that dissolves paint such as acetone. Names fired into the enamel will not be affected by the solvent whereas names painted on later will dissolve and wash off, leaving the original enamel details of the dial intact.
Some Thoughts on Dial Refinishing
Bear in mind that removing the paint is easy, putting it back to match the original is difficult. I would recommend that you take some close up pictures of the dial and hands and send them to several companies. Give a detailed description of what you want doing and ask them if they can do it in the way that you wish. If you want the dial and hands to look exactly like they do now, paint colour and finish included, make sure you say so. Be as detailed as you can in describing what you want, don't imagine that they will know. Take up references and do your due diligence before committing your dial to them.
Think carefully about getting radium paint on an early dial replaced with luminous paint. The old radium paint no longer glows in the dark, so if you replace it with luminous paint which does, it will be obvious what has been done. I think this is a good thing, it makes it obvious that the paint is a modern luminous compound and not the old, non glowing, radium based lume.
I have used a couple of UK based dial repainters, but they tend to be quite expensive. US dial refinishers seem to be cheaper because they have a greater market and therefore are able to work on a larger scale, more commercial basis. A poll on the NAWCC message boards recommended a number of US dial refinishers, with International Dial Co. coming out as the clear winner. Next time I need a dial refinishing I am going to give them a try, and I will record the outcome here. NB: I haven't used International Dial Co. yet, and I don't have any connection with the company, so this is not a personal recommendation from me, I am just going on the results of the NAWCC poll.
The style of the hands should match the dial. In particular, if the numerals are skeletonised for luminous paint, the hands should also be skeletonised.
Hands should also be the right length. The minute and seconds hands should terminate on their respective tracks, and the hour hand should point to or just touch the number.
Copyright © David Boettcher 2006 - 2017 all rights reserved. This page updated December 2016. W3CMVS.