A relatively new material for furniture construction, plastics come in so many different varieties that generalization becomes difficult. Price increases of recent years (most plastics are petroleum-based substances) have somewhat set back earlier expectations that plastics would become the primary material for furniture making. Still, many modem designs use plastic parts, and certain plastics are widely used for special applications. Its most visible application in furniture is probably as stet laminate, used as a tough surface material .
Laminates are composed of layers of heavy paper impregnated with melamine resin. Plain colors, patterns, and imitations of wood grain are common surface finishes. The thickness of the laminate shows as dark brown or black at the edges unless they are trimmed in some way. Some recently developed laminates, of uniform color throughout their thickness, do not create edge-appearance problems.
Acrylics (such as Plexiglas or Lucite, to mention two well-known trade names) resemble glass in their transparency. They also can be made translucent and colored. While less subject to breakage than glass, they scratch more easily and attract dust and lint with static electrical charges. Acrylics can be bent and molded into curved shapes and are used mostly to make transparent parts and occasionally entire pieces of furniture.
Molded plastics, such as styrene, polyethylene, nylon, and vinyl, are often made into small parts for special purposes such as glides, rollers, edge trim, and drawer pulls. The only other plastic sufficiently strong and moderate enough in cost to be usable for major furniture parts is fiberglass, a hybrid material in which glass fibers are embedded in a molded polyester resin.
It is commonly used to make custom auto-body parts and small boat hulls. Fiberglass chair shells can be molded to body conforming shapes that are very strong and durable when well designed. The plastic may be exposed, painted, or covered with upholstery padding.
Fiberglass chair shells can be tested for strength with deliberate rough handling, in testing machines, and through observation of chairs in regular use. The sight of broken plastic shells is common in public spaces, which impose the harsh tests of heavy use and, sometimes, deliberate vandalism.
Chair shells made of plastic softer than fiberglass, used in many designs, cannot be expected to stand up to this kind of heavy usage. A fair test of any plastic chair is to kneel in the seat and try to tear loose the back by pushing back and pulling forward. Also, test leg or base connections to the chair body; they should be unbreakable in any reasonable form of rough treatment.
Foamed plastics have become favorite materials for cushions, mattresses, and padding in upholstery. Foam takes the form of slabs, thin sheets, or molded parts shaped into cushions or fitted to entire chair forms. Upholstery foams vary greatly in degrees of softness,durability, and resistance to fire.
Poor quality foams do not hold up well, and some foams produce toxic fumes when burning. The quality of foams can only be verified through manufacturers specifications and guarantees, since testing calls for laboratory techniques.Plastic foams can also be made stiff enough to be called rigid. Combinations of soft and rigid foam are used in some modern upholstery, either alone or with embedded frames of wood or metal or with bracing panels of wood, metal, other plastics, or fiber.
Evaluating such hybrid plastic furniture is somewhat difficult, since the construction is concealed in the finished product. Testing for comfort, durability against hard use, and similar characteristics can be done fairly easily by sitting in each piece, moving in it, and deliberately trying to break it. Durability in service over a long period can be tested only by the products service record, so any new construction material should be approached with caution.
Given a structural framework of a stronger material, such as wood or metal, rigid foam, with a plastic surface finish, can also be used as the primary material of storage furniture. This technique is currently used to create mass-produced furniture of minimal quality with surfaces colored to simulate wood. Its potential for use in well-designed furniture of higher quality will probably be developed eventually.
This is a technique using a variety of materials to create softness in seating and reclining furniture. Upholstery can range from a thin pad added to a hard seating surface to a complex construction that provides excellent comfort. Since a covering of fabric, leather, or plastic usually conceals all upholstery construction, its techniques and quality are hard to evaluate. Inspecting an upholstered unit before it is covered or watching the upholsterer at work in the shop are the best ways to become acquainted with upholstery techniques.
Traditional upholstery, still used in many quality products being with a frame, sturdily made in hardwood, with strong joints .This establishes the outer form of the finished unit. The open bottom is laced with an over-and-under weave of heavy webbing. Onto this, a number of coil springs (16 to 25 per seat) are tied and sewn to be pulled down into a partially compressed position. Canvas is placed over the springs and a cushion added on top. The cushion may be a removable unit or sewn down in place. The back is similarly treated, often without the coil springs. Padding is placed on arms and edges, and the whole is covered with the material that will be visible in the finished product.
Traditional upholstery, which depends on skilled labour, is slow and costly to produce. Most modern variations stem from efforts to reduce this labor cost. For example, flat, sinuous springs or elastic webbing often take the place of coil springs. Plastic foam (discussed above) may replace older cushioning materials, such as down, felt, or cotton, or various grades of foam may make up the entire upholstery construction.
The resulting comfort can be evaluated by direct trial. Durability is again, harder to evaluate. Upholstered furniture made with good workmanship using good materials can have a long life, but upholstery using shortcut methods and cheap materials can be a doubtful economy, leading to the dismembered examples so often discarded after a short life. The reputation of a particular manufacturer is again the best guide to quality.