PROTECTIVE COATING

In watchmaking, protective coating is a temporary protection — varnish, lacquer or sticker — applied to certain parts of a component to protect them during an operation, before being removed. The principle consists of “protecting”, meaning masking an area that should not be altered, while another is being treated. For example, the inside of a gilded engraving will be protected before rhodium-plating a bridge, so that the rhodium deposit does not cover its case back; or a neighboring satin-finished surface will be protected before polishing an adjacent area, so as not to damage its finish. Protective coating is therefore essential whenever a component combines several finishes or surface treatments incompatible. Its application requires precision and cleanliness: a poorly applied protective coating lets the treatment through or spreads beyond its limits, ruining the result. A discreet but essential technique, it ensures the coexistence of contrasting finishes on the same component.