Techniques of Enamelling
- Stencils sets -
The stencils were made, either according to a model
or according to a drawing or text composed by the draughtsman himself. We used an extra paper for stencil which cut out rather easily. But for our large orders we needed especially a very resistant stencil . It is for this reason that we manufactured stencils in zinc sheet. A paper stencil resisted the brush only for 60 or the maximum 100 signs,
while the zinc stencil there was practically no wear, only small breaks or cracks which were repaired by a welding.
The zinc stencils were done in the following way:
we covered the 2 zinc sides with a layer of asphalt, then we used the stencil model (cut out in paper) to reproduce this cutting on the zinc sheet by tracing all the cut out borders using a needle. Then we soaked these sheets in a bath of hydrochloric acid, which tackled the layouts and made fall the nondesired parts 1 minute later. "
According to Arthur Baumgarten
- Brushing -
Before the sheets do arrive in the brush workshop, it was necessary to give them a layer of enamel (the desired colour according to model). The application of the colours was done either with a ladle while letting run the enamel, or with an compressed-air gun. After drying the sheets were ready for the brush.
Brushing itself was done, not only with positive stencil sets but also with negative stencil sets, because at the Emaillerie we worked in inverse way ,that is to say
instead of giving a layer, we removed a great part of it. In general a stencil
set was used to reproduce a subject or text by covering the
stencil by a coat of paint. For the enamelled sign it was the opposite. Since the desired colour was already applied by the enameller, it was necessary, with the aid of a stencil,
to remove superfluity.
Let us take for example a sign with black background and white text: In this case the black enamel was applied to an already cooked white layer. With the positive stencil (openwork letters) we emphasized the text in white with the brush.
Other example. White background and black text - For that a negative stencil was
neede. The preparation of the enamel was like describe in the previous example, but the stencil was cut out in such way that the text remained and that border of the letters was removed to emphasize the white zone.
One more precision. A complete stencil key set was always in
two parts; we could not cut out the whole in only once, because
we needed supports to attach certain parts. Those were then cut
out with a second stencil (see 'A sign was born').
After the brush operation follows the cooking, and this for each hue.
This long and painful process, with individual cooking was replaced later by the serigraphy which allowed an already worked installation and only one cooking for all the colours. "
According to Arthur Baumgarten
- Serigraphy -
Being obliged to find a more rational and more
profitable way, because competition was large and our printed signs
became too expensive, we decided to test with the screen prints process, which at that time (about 1950) was not yet or badly known in the emailleries. It did not exist yet the vitrifiable paste for the process, and even the hardware to make the stencils was difficult to find. At the beginning we could import it from America and also from Germany; then 3 to 4 years later it was possible to get the whole in France, even the necessary equipment
for the manufacture of the photomechanical stencil.
The advantages of the Serigraphy process were enormous: reduced working hours, net and clean work (without final improvements) and only one cooking for all the colours applied. In more costs reduction, no more need for lithographers and highly
remunerated printers; employees compression thus meaning rather significant save allowing to sell less expensive.
A serigraphy stencil set was composed of nylon tissue or
silk tended on a wooden framework, on which was fixed a special film. The fixing or joining of this film was done by applying the framework tended on the film and by passing a moistened rag of cellulose thinner. The film was stuck immediately on the nylon tissue.
For the end, it was necessary to make the tissue quite tight around the framework in order to only let the paste pass through the openwork drawing. "
According to Arthur Baumgarten
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