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SUPPORTS, FIXTURES & FITTINGS
The majority of art and design casts contain some type of set-in fixture which can be used as a means of securing the finished sculpture to a base, wall or similar feature. Fixings and fittngs for casts are normally supplied by the founder. In most cases the fixings used are of a straightforward design, simple both to attach to the cast itself and then secure it to a mount. Occasionally the size, design or positioning of a sculpture requires a more elaborate or substantial fixing to be specified and fitted. This page looks at some of the circumstances affecting the choice of fixing, and the typical solutions used by founders to secure art and design casts.
STANDARD FIXTURES & FITTINGS (FOR BASES & PLINTHS)
Foundries have evolved various systems for securely fixing common types of art casts (heads, busts, figures etc), to bases, plinths and other mounting features. The simplest method usually involves the supply of a threaded STUD or BOLT, which is accommodated on the sculpture by a tapped FLANGE or BOSS added to the cast. One end of the stud can be screwed into the cast’s flange/boss, the other end is inserted into the CLEARANCE HOLE drilled into the mount, this end is then secured either with a nut and washer from under the mount, or permanently fixed using a suitable resin capsule or injected compound.
Flange and boss plates for the cast can be modelled in wax, then attached to a convenient point on the sculpture, usually on the inside of the WAX PATTERN during the wax’s preparation for INVESTMENT. The flange then becomes an integral part of the cast’s fabric. Alternatively, the founder will weld a pre-cast metal plate onto the finished cast before patination. The metal flange or boss may then be drilled and tapped with a suitable THREAD for locating a stud fixing. Where available, WHITWORTH (BSW) threaded studs are preferred over METRIC (M) for use with relatively soft alloys like gunmetal, the coarse pitched BSW thread is less likely to be stripped or pulled out of place under load.
Once the flange has been tapped, a TEMPLATE can then be made to accurately describe the position of the fixing(s) on the sculpture. The template can then be used to locate the position of clearance holes on remotely situated plinths and bases, in advance of the finished work’s delivery and installation.
Under normal circumstances, the price quoted by an art founder for the cast will include the fitting of a flange to the cast and the supply of a standard type stud fixing. In the vast majority of cases the founder’s standard fixing will be more than satisfactory and perfectly adequate to securely mount and support the finished work. The founder will also be able to supply information about the fixing (stud diameters, thread types, positional templates etc), these details will enable installation contractors to prepare in advance a plinth or any other feature designed to receive the cast.
Like any other unusual or unique item, the supply or fit of a non-standard fixing should be discussed and agreed in advance with the founder. Given that special fixings are often more expensive to obtain and fit than standard solutions, the founder may adjust any earlier estimate or quotation to take account of any additional costs involved.
Legal responsibility for ensuring the suitability and serviceability of fixings and other safety features can be something of a ‘grey area’. If a structural engineering contractor has been retained to design a fixing, it is normally their responsibility to ensure the overall design and specification is both safe and adequate for it’s stated purpose. Correct installation (for instance the tightening of restraining bolts to a specified torque), is normally the responsibility of either the founder or other installation contractor carrying out that aspect of the job. Anyone carrying out formal design or installation work should be qualified to undertake this type of work (where applicable), contractors should also hold adequate insurance policies. Any doubts or concerns about the suitability of a support design or the material specified for a fixing should be discussed with the founder or other responsible person. Consultancy fees (for structural engineers and other professionals), are normally met by the client (ie the artist, designer or commissioning body for example). Likewise, costs incurred for testing materials and structures (sometimes referred to as NON-DESTRUCTIVE TESTING or ‘NDT’ [see SUPPLEMENT]) are also usually charged to the client.
It should be stressed that the majority of art foundry projects need not undergo detailed engineering surveys, extensive testing, or indeed have any extra internal support structure added. Whilst safety considerations must be paramount, the measures taken to secure a work should be always be consistent with needs, rather than overly excessive.
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