< FITTING A CAST TO AN EXISTING STRUCTURE
JOINING & CUTTING
Unlike sculptural designs WROUGHT from mill supplied sheets and sections, a sculpture cast is usually formed entirely within a refractory mould. This means that a cast needs little, if any, further manipulation – bending, rolling, forging etc, to complete the sculpture. Despite this, few cast designs are completed in the foundry without having undergone some degree of cutting or welding process.
As well as producing cast designs and sculptures, founders may occasionally fabricate wrought elements. Wrought elements may be intended as an additional visual feature to be set in the cast design itself, or else as a support feature – such as a metal plinth, base, armature and so on. Whilst few foundries possess the tooling or machine facilities of a dedicated fabrication shop, many larger founders offer some form of basic fabrication service, usually adequate for producing the kinds of straightforward fabrications mentioned above.
Modern art foundries invaribly use full fusion techniques (WELDING), as well as BRAZING and SOLDERING processes for joining cast elements [ref]. To a lesser extent bolts, self tapping screws and rivets of varying types are used to create so called DRY JOINTS. Most commonly, dry joints are used for the fixing of an internal armature support to the walls of a cast. Cast iron designs will often be bolted in preference to welding, in this instance the mechanical joint minimises the potential for a fracture to be initiated in the cast through welding heat stress. Other techniques such as glued or ‘self secured’ joining (shrink fitted or 'panned’ down for example), are not commonly found in cast artworks, these joining techniques are only used in exceptional circumstances.
The following sections introduce some of the processes and techniques used in art foundries and other design metal workshops to join and cut a variety of materials.
WELDING, BRAZING & THERMAL CUTTING INTRODUCTION >
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NOTE: The word WROUGHT is used here as a general reference to any readily available stock metal item, including plate, tube, bar, angle and so on. |
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