< FUME PATINATION
BURIED & COVERED PATINATION
A patina can be produced by burying or covering the cast object with an absorbent medium saturated with an active chemical compound. Media considered suitable for carrying chemical solutions include soil, shredded paper, sawdust, cotton wool and cloth for example. These are relatively inert materials which do not severely react with either the added in chemical, or the metal in the cast, this neutrality is essential for controlled and predictable results.
The cast is normally placed onto a layer of the treated medium contained in a box which is also constructed from a neutral material (a treated/low resin content wood, or plastic for example). The remainder of the medium is then used to completely bury the cast, before the box is sealed shut. It may be necessary on occasion to open the box and recharge the medium with fresh chemical, especially if the patina is of a slow developing variety. Alternatively, cast sculpture can be treated with a POULTICE that is directly applied to it’s surface. The poultice can be prevented from drying out by wrapping around with plastic food film.
Artificial burial techniques are designed to accelerate and reproduce the colouring effects developed on cast’s as a result of their extended burial in natural conditions. Though these patination techniques can evolve some exceptionally subtle (if sometimes unpredictable) colourings, they are not commonly used in professional art foundries. The lack of popularity here is principally due to the significant period of time it can often take for a substantial patina deposit to develop. Sculptures coloured by a burial technique can also potentially develop a heavy or uneven patina, with some types of concentrated chemical attacking the very fabric of the cast to produce a severely cracked, pitted or encrusted surface. Although a buried patina can be exceptionally attractive on appropriate designs, a patination induced by this method can be notoriously difficult to control, especially when compared to more common techniques like the torch method.
PATINA FINISHING & PROTECTION >
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