GENERAL ENGINEERING & FABRICATION TECHNIQUE
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soft drink bottles, and milk jugs are examples of products made through this process. Rotational Molding – Plastic pellets can be placed into a mold and heated to a liquid state, or two or three-part resin systems are mixed and poured into a mold. The mold is turned on one or two separate axes to evenly spread the material until it hardens. This process commonly produces hollow objects, but is also useful for solid objects. It is commonly utilized for asymmetrical objects like toys, kayak bodies, and resin cast sculpture.
ENVIRONMENTAL CONCERNS Plastic engineering has made tremendous advances over the past 50 years. Many polymers are now created to withstand prolonged exposure to harsh chemicals and solvents; however, there are environmental limits to the appropriateness of plastic when used in public artwork.
DURABILITY Industrially produced plastic objects are classified within the plastics industry as durable or non-durable67. Products with a useful life of over three years are considered durable, e.g. appliances, plumbing materials, home siding. However, due to environmental considerations, many products are being engineered with a useful life of less than three years, which are considered non-durable, e.g. water and soda bottles, trash bags, food delivery systems. Essentially, any plastic that is created for short term use is likely engineered to be non-durable. Artists wishing to use found objects in their artwork should avoid using non-durable plastic objects as they are not designed to have an adequate lifespan for public artwork.
ARTWORK VS. FUNCTIONAL PROTECTIVE COMPONENTS When considering the use of plastic in exterior environments, a distinction must made between what is the artwork, and what is a functional component designed to protect the artwork. For instance, a cast acrylic relief would be considered the artwork, but a protective cover of polycarbonate over the relief would be considered a functional component designed to protect the artwork. WSAC requires functional components be designed to be easily replaceable, both in terms of how they are attached to the artwork and the ability to purchase a comparable replacement through a third party vendor. American Chemistry Council, Inc. Plastics 101: life cycle of a plastic - Production Processes. Learning Center: Plastics Division. <www.americanchemistry.com> 67
This distinction is important as WSAC does not consider plastic artwork to be acceptable in exterior environments. However, WSAC does consider functional components made of plastic that are designed to protect the artwork to be appropriate for some exterior artwork, e.g. nylon or Teflon dielectric gaskets to isolate dissimilar materials, polycarbonate sheet to protect glass or neon artwork from vandalism, polyurethane and epoxy adhesives for joining materials, polyethylene vapor barriers for some terrazzo and concrete flooring systems, or acrylic latex paint to color and protect wood.
DETERIORATION OF PLASTICS FOR MORE DETAILS VISIT US ON WWW.IMTSINSTITUTE.COM OR CALL ON +91-9999554621