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Thursday, 24 March 2011 14:53

Sculpture

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In ancient times, the art of sculpture included engraving and carving of stone, wood, bone and other materials. Later, sculpture developed and refined modelling techniques in clay and plaster, and moulding and welding techniques in metals and glass. During the last century various additional materials and techniques have been used for the art of sculpture, including plastic foams, paper, found materials and several sources of energy such as light, kinetic energy and so on. The aim of many modern sculptors is to involve the viewer actively.

Sculpture often utilizes the natural colour of the material or treats its surface to achieve a certain colour or to emphasize the natural characteristics or to modify the light reflections. Such techniques belong to the finishing touches of the art piece. Health and safety risks for artists and their assistants arise from the characteristics of the materials; from the use of tools and equipment; from the various forms of energy (mainly electricity) used for the functioning of tools; and from heat for welding and fusing techniques.

Artists’ lack of information and their focusing on the work lead to underestimating the importance of safety; this can result in serious accidents and the development of occupational diseases.

The risks are sometimes linked to the design of the workplace or to the organization of the work (e.g., carrying out many working operations at the same time). Such risks are common to all workplaces, but in the arts and crafts environment they can have more serious outcomes.

General Precautions

These include: appropriate design of the studio, considering the type of power sources employed and the placement and movement of the artistic material; segregation of hazardous operations controlled with adequate warning displays; installation of exhaust systems for control and removal of powders, gases, fumes, vapours and aerosols; use of well-fitted and convenient personal protective equipment; efficient clean-up facilities, such as showers, sinks, eye-wash fountains and so on; knowledge of the risks associated with the use of chemical substances and of the regulations that govern their use, in order to avoid or at least reduce their potential harm; keeping informed on the possible risks of accidents and on hygiene regulations and being trained in first aid and. Local ventilation to remove airborne dust is necessary at its source, when it is produced in abundance. Daily vacuum cleaning, either wet or dry, or wet mopping of the floor and of work surfaces is highly recommended.

Main Sculpturing Techniques

Stone sculpture involves carving hard and soft stones, precious stones, plaster, cement and so on. Sculpture shaping involves work on more pliable materials—plaster and clay modelling and casting, wood sculpture, metalworking, glassblowing, plastic sculpture, sculpture in other materials and mixed techniques. See also the articles “Metalworking” and “Woodworking”. Glassblowing is discussed in the chapter Glass, ceramics and related materials.

Stone sculptures

Stones used for sculpture can be divided into soft stones and hard stones. The soft stones can be worked manually with tools such as saws, chisels, hammers and rasps, as well as with electric tools.

Hard stones such as granite, and other materials, such as cement blocks, can be used to create works of art and ornaments. This involves working with electric or pneumatic tools. The final stages of the work can be partially executed by hand.

Risks

Prolonged inhalation of high quantities of certain stone dusts containing free crystalline silica, which comes out of freshly cut surfaces, can lead to silicosis. Electric and pneumatic tools can cause a higher concentration in the air of dust which is finer than that produced by manual tools. Marble, travertine and limestone are inert materials and not pathogenic to the lungs; plaster (calcium sulphate) is irritating to the skin and to the mucous membranes.

Asbestos fibre inhalation, even in small quantities, can lead to a risk of lung cancer (laryngeal, tracheal, bronchial, lung and pleural malignancies) and probably also cancer of the digestive tract and of other organ systems. Such fibres can be found as impurities in serpentine and in talc. Asbestosis (fibrosis of the lung) can be contracted only through the inhalation of high doses of asbestos fibres, which is unlikely at this type of work. See table  1 for a list of the hazards of common stones.

Table 1. Hazards of common stones.

Hazardous ingredient

Stones

Free crystalline silica

 

Hard stones: Granites, basalt, jasper, porphyry, onyx, pietra serena

Soft stones: steatite (soapstone), sandstone, slate, clays, some limestone

Possible asbestos contamination

Soft stones: soapstone, serpentine

Free silica and asbestos

 

Hard stones: marble, travertine

Soft stones: alabaster, tufa, marble, plaster

 

High noise levels can be produced by the use of pneumatic hammers, electric saws and sanders, as well as manual tools. This can result in hearing loss and other effects on the autonomic nervous system (increase of heart rate, gastric disturbances and so on), psychological problems (irritability, attention deficits and so on), as well as general health problems, including headaches.

The use of electric and pneumatic tools can provoke damage to finger micro-circulation with the possibility of Raynaud’s phenomenon, and facilitate degenerative phenomena to the upper arm.

Work in difficult positions and lifting heavy objects can produce low-back pain, muscle strains, arthritis and joint bursitis (knee, elbow).

The risk of accidents is frequently connected with the use of sharp tools moved by powerful forces (manual, electric or pneumatic). Often stone splinters are violently shot into the working environment during the breaking of stones; falling or rolling of improperly fixed blocks or surfaces also occurs. The use of water can lead to slipping on wet floors, and to electric shocks.

Pigment and colourant substances (especially of spray type) used to cover the final layer (paints, lakes) expose the worker to the risk of inhalation of toxic compounds (lead, chromium, nickel) or of irritating or allergenic compounds (acrylic or resins). This can affect the mucous membranes as well as the respiratory tract.

Inhalation of evaporating paints solvents in high quantities over the course of the working day or in lower concentrations for longer periods, can provoke acute or chronic toxic effects on the central nervous system.

Precautions

Alabaster is a safer substitute for soapstone and other hazardous soft stones.

Pneumatic or electric tools with portable dust collectors should be used. The working environment should be cleaned frequently using vacuum cleaners or wet mopping; adequate general ventilation must be provided.

The respiratory system can be protected from the inhalation of dusts, solvents and aerosol vapours through use of proper respirators. Hearing can be protected with ear plugs and eyes can be protected with proper goggles. To reduce the risk of hand accidents leather gloves (when necessary) or lighter rubber gloves, lined with cotton, should be used to prevent contact with chemical substances. Anti-slipping and safety shoes should be used to prevent damage to the feet caused by the possible fall of heavy objects. During complicated and long operations, proper clothes should be worn; ties, jewellery and clothes which could easily get stuck in the machines should not be worn. Long hair should be put up or under a cap. A shower should be taken at the end of every work period; work clothes and shoes should never be taken home.

Pneumatic tool compressors should be placed out of the work area; noisy areas should be insulated; numerous breaks should be taken in warm areas during the working day. Pneumatic and electric tools equipped with comfortable handles (better if equipped with mechanical shock absorbers) which are able to direct the air away from the hands of the operator should be used; stretching and massage are suggested during the work period.

Sharp tools should be operated as far as possible from hands and body; broken tools should not be used.

Flammable substances (paints, solvents) must be kept far from flames, lit cigarettes and heat sources.

Sculpture shaping

The most common material used for sculpture shaping is clay (mixed with water or naturally soft clay); wax, plaster, concrete and plastic (sometimes reinforced with glass fibres) are also commonly used.

The facility with which a sculpture is shaped is directly proportional to the malleability of the material used. A tool (wood, metal, plastic) is often used.

Some materials, such as clays, can become hard after being heated in a furnace or kiln. Also, talc can be used as semi-liquid clay (slip), which can be poured into moulds and then fired in a kiln after drying.

These types of clays are similar to those used in the ceramic industry and may contain considerable amounts of free crystalline silica. See the article “Ceramics”.

Non-hardening clays, such as plasticine, contain fine particles of clays mixed with vegetable oils, preservatives and sometimes solvents. The hardening clays, also called polymer clays, are actually formed with polyvinyl chloride, with plasticizing materials such as various phthalates.

Wax is usually shaped by pouring it into a mould after it is heated, but it can also be formed with heated tools. Wax can be of natural or synthetic compounds (coloured waxes). Many types of waxes can be dissolved with solvents such as alcohol, acetone, mineral or white spirits, ligroin and carbon tetrachloride.

Plaster, concrete and papier mâché have different characteristics: it is not necessary to heat or to melt them; they are usually worked on a metal or fibreglass frame, or cast in moulds.

Plastic sculpture techniques can be divided into two main areas:

  • work with already polymerized materials (casting, plate or sheet). They can be heated, softened, glued, cut, refined, refurbished and so on.
  • work with non-polymerized plastic. The material is worked with monomers, obtaining a chemical reaction leading to polymerization.

 

Plastics can be formed by polyester, polyurethane, amino, phenolic, acrylic, epoxy and silicon resins. During polymerization, they can be poured into moulds, applied by hand layup, printed, laminated and skimmed by using catalyzers, accelerators, hardeners, loads and pigments.

See table 2 for a list of the hazards and precautions for common sculpture shaping materials.

Table 2. Main risks associated with material used for sculpture shaping.

Materials

Hazards and precautions

Clays

 

Hazards: Free crystalline silica; talc can be contaminated by asbestos; during heating operations, toxic gases can be released.

Precautions: See “Ceramics”.

Plasticine

 

Hazards: Solvents and preservatives can cause irritation to skin and mucous and allergic reactions in certain individuals.

Precautions: Susceptible individuals should find other materials.

Hard clays

 

Hazards: Some hardening or polymer clay plasticizers (phthalates) are possible reproductive or carcinogen toxins. During heating operations, hydrogen chloride can be released, especially if overheated.

Precautions: Avoid overheating or using in an oven also used for cooking.

Waxes

 

Hazards: Overheated vapours are flammable and explosive. Acrolein fumes, produced by decomposition from overheating wax, are strong respiratory irritants and sensitizers. Wax solvents can be toxic by contact and inhalation; carbon tetrachloride is carcinogenic and highly toxic to the liver and kidneys.

Precautions: Avoid open flames. Do not use electric hot plates with exposed heating elements. Heat to minimum temperature necessary. Do not use carbon tetrachloride.

Finished plastics

 

Hazards: Heating, machining, cutting plastics can result in decomposition to hazardous materials such as hydrogen chloride (from polyvinyl chloride), hydrogen cyanide (from polyurethanes and amino plastics), styrene (from polystyrene) and carbon monoxide from the combustion of plastics. Solvents used for gluing plastics are also fire and health hazards.

Precautions: Have good ventilation when working with plastics and solvents.

Plastics resins

 

Hazards: Most resin monomers (e.g., styrene, methyl methacrylate, formaldehyde) are hazardous by skin contact and inhalation. Methyl ethyl ketone peroxide hardener for polyester resins can cause blindness if splashed in the eyes. Epoxy hardeners are skin and respiratory irritants and sensitizers. Isocyanates used in polyurethane resins can cause severe asthma.

Precautions: Use all resins with proper ventilation, personal protective equipment (gloves, respirators, goggles), fire precautions and so forth. Do not spray polyurethane resins.

Glassblowing

See Glass, ceramics and related materials.

 

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