restoration of silvered dials

When restoring silvered dials I always use the least means necessary to achieve the required result. In the following four examples, the last was the only one for which I used an all-over application of the silvering powder. The first three were simply rubbed over with cream of tartar finishing powder, and areas of heavy loss were touched in with the application of silvering powder on a cotton bud. None of the dials had their underlying surfaces refinished. All of them were coated with microcrystalline wax after treatment to provide protection against atmospheric moisture and custodian’s fingers when hand setting. This approach leads to minimal loss of historic material and information, and is also the most cost-effective for the client. See the bottom of this page for more information about why I use this process.

The silvering on clock dials often becomes worn or damaged with age. This can be caused by the hands touching on the dial, or even by the accumulated years of owner’s fingers touching the dial to set the hands. Equally, atmospheric pollution can corrode the silver layer to form dark or opalescent patches of silver sulphide. In order to refresh damaged silvering, some restorers will advocate complete refinishing of the dial with abrasive paper to form a homogenous surface before applying the silvering layer. For dials with heavy damage (such as deep scratches and dents) and substantial losses of the wax numerals, such considerable intervention may be required to provide an acceptable result. However, this kind of refinishing should only be used in extreme circumstances, as the associated removal of material results in loss of historic information. The fine detailing and crisp edges of engraved numerals and signatures are quickly lost, as are any inked (rather than engraved) signatures. Multiple instances of this kind of treatment can result in more substantial areas of shallow engraving being lost altogether. Also, the ‘grained’ finish that abrasive papers leave on a dial is often not appropriate to the period of the clock and is not an accurate reflection of its original condition.

An over-willingness to refinish dials often belies a misunderstanding of the science behind the silvering method - The chemical process that is taking place is generally adequate to remove patchy areas of corrosion, the silvering powder itself is a mild abrasive and can, in most situations, achieve a result that significantly improves the aesthetic appearance of the dial whilst retaining some level of historic character and not leading to an over-restored appearance. Cream of tartar is often used as a finishing powder in the silvering process to brighten up a recently treated surface, in instances of only mild damage an application of this finishing powder may be all that is needed to see significant improvement.