Care of bronzes
All patinas can be affected by various proprietory waxes due to the varied solvents used in wax polishes. Never treat a bronze with a wax containing silicone.
Indoor bronze patinas need very little care, an occasional dusting will keep the artists intended surface. Very smooth polished surfaces may be enhanced by a thin layer of transparent furniture polish such as "Antiquax". Be very economical in how the wax is applied, generally a clean soft brush is used to apply a thin layer of wax. It is advisable to wrap any metal parts of brushes with masking tape in order to eliminate the possibility of scratching the patina whilst applying the wax.
As the wax sets on the surface but before it dries hard, a soft shoe polishing brush or equivalent is used to buff up a preliminary shine then with a clean soft cloth a high sheen is achieved by vigorous rubbing.
Please note that some modern patinas, especially those based on the white patina chemical "Bismuth Nitrate" which includes most pastel colours should not be done except with expert advice. Solvents in wax can drastically change the colour in the most delicate of patinas.
If in doubt always ask the Gallery before attempting to re-polish a bronze. It is seldom anything other than a dusting that is really necessary.
Outdoor bronze patinas are subject to the chemical action of the environment they are placed in, and the sulphides, chlorides, nitrates or acid in the rain or air will inevitably have an effect on the surface patination of a sculpture. Most sculptors are well aware of the nature of patina change outdoors and either restrict the colours chosen for bronzes or accept that change however unpredictable is part of a sculpture becoming at one with its environment.
Regular waxing of a recently cast bronze can however delay the process of a patina changing. This is done in the same way as a small indoor bronze but first the sculpture should be washed with luke warm water and a weak detergent or washing up liquid, then make sure that the bronze is completely dry before applying a layer of wax. On large sculptures the waxing should be done in sections so that the wax doesn't set too hard before the final buffing otherwise the polish will never really get to high a gloss. In very hot weather do not attempt to wax a bronze should it be hot as this can also change the colour of the patina drastically – wait for it to cool down ie at night or early in the morning.
These notes are a guide only, they do not pretend to cover all aspects of looking after sculpture and no responsibility can be accepted for any untoward changes in the appearance of bronzes. If in any doubt about treating bronze sculpture, always seek the advice of the Gallery.
© Sladmore Gallery Ltd 2011