< PATINATION (RED)
ALTERNATIVE PROTECTIVE COATINGS
Whilst the application of a fine wax product is the standard means of finishing and protecting a patina; lacquer, varnish and modern synthetic materials (polyurethane, modified acrylics, epoxy and cellulose for example), can also be used as an alternative. In some cases, for example if the cast is to be situated in a particularly arduous environment, an alternative coating may provide a more satisfactory and durable protection than that offered by a wax.
Lacquer coatings are also occasionally preferred as a protective coating for highly polished metalworks (products are available under various trade names including ‘Incalac’ and ‘Permalac’). When used, a lacquer or varnish protection must be applied according to the individual manufacturer’s instructions, usually either by brush, or via an atomised spray. As with any other protective application, care is taken not to disturb the delicate underlying patina or polish – in such circumstances the spray diffuser method may prove preferable to the more direct, if potentially abrasive, brushing method. Some of the more durable lacquers require baking on in a stove enamelling type process, typically to temperatures of about 200°F (100°C), this can mean that these products are unsuitable for use on larger sculptural designs.
Not all lacquer coatings are ideal for out of doors use. In general modified acrylic, cellulose and soluble fluro polymer based materials are best suited for exterior use, though prior research is essential to identify the optimum product for a particular purpose. Before applying any alternative or untried coating, it is prudent to prepare a suitable sample and test for short term longevity and potentially adverse reactions. Bear in mind that even the best lacquer products only have a life expectancy of 20 years or so, after which stripping and re-coating becomes necessary.
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