First, as a pre-treatment, the metal is washed in acid and the oil removed. Then the undercoat is applied and left to dry before the enamel glaze is applied. It is then dried again, fired, inspected, and shipped.
The undercoat is a key determinant of the overall quality of the dial. It’s the most crucial step. If the undercoat is too thin then the dial will be prone to flaws, and if it is too thick then not only will it exceed model standards but achieving the correct coloration will also become more difficult. The standard range is from 0.10mm to 0.12mm, with the latter being the ideal thickness.
You can do it by timing the application, or you can use your intuition to judge it visually. Looking at the degree of wetness of the dial surface, you can gain some insight into the thickness of the coat and gauge how much further to go to achieve the optimum level.
I’m told that Seiko has used enamel dials since the Laurel, but with the Presage, some design elements have changed. The watch face design now has more than three hands, an inset sub-dial, and open date window. As the design changes, so does the approach to enamel application. The technique and grip on the spray gun to apply the enamel must change as much as the composition of the enamel glaze itself. The process requires harmony between brain, eyes, and hands to adapt to each individual design to create a quality product.
And not just that, the weather can also affect the finish. In an environment where the humidity drops during hot summer weather, the way the applied enamel glaze dries becomes changeable, making it easier for irregularities to occur. Of course we have data that allows us to maintain consistent quality during changing atmospheric conditions, so it’s possible to match the process to the weather, but then things like sudden evening showers occur… You can see how sudden changes in environment may even stop the work process. The best weather conditions are on cloudy days from autumn to spring.
As there are a number of processes involved, it’s difficult to work out a definite number per day, but I’ve settled on a routine of half a day of pre-treatment with the coating process on the following day. However, there are no do-overs with this work so, factoring in the final checks, I produce about 200-250 finished dials a month.
Honestly, I feel relieved (laughs). It’s not just me, but a lot of people contribute to the finished watch. However, if there is a delay in my part of the process, it creates trouble for everyone. Therefore I take care to make the deadline.
Enamel has a unique beauty, and what I think is amazing about that beauty is that it will not fade over years or even decades. Moreover, although it depends on how it’s used, a feature of enamel in cookware is that it improves the taste of food. Plain stainless steel or aluminum cookware can impair the taste slightly, but it’s said that with enamel you don’t get this.
At the moment I’m putting my efforts into staff training. The reason I’m trying to capture as much of my enamel processing know-how as possible as quantifiable data is to aid in this training. If I can cultivate artisans who know how to make use of this data, they will be able to inherit my enamel dial production techniques.