Furniture Structure and Materials • •
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Quality of materials and technique in furniture construction has a major impact on both its durability and its proper use. Generally the details of construction of a piece of furniture are at least partially concealed in the finished piece. Because of this, the reputation of a particular manufacturer, published specifications, and price are all clues to the quality of construction. Well made furniture need not be expensive, but cheap duplicates of high quality products are almost always the result of some skimping on materials, or details of construction. Good furniture is not weak, fragile, or shaky when new, and will not develop weaknesses with normal use over long periods of time.
Furniture General Guidelines • Just how sturdy a piece of furniture needs to be depends on its intended use. • Many fine antiques that have held up for centuries are quite delicate, but they have been used only under conditions that do not impose too much rough usage. • Delicate materials and finishes can survive in private living spaces or in executive offices better than in hotel rooms, dormitories, or where young children will be regular users. • Whatever its intended use, good furniture is characterized by good materials, techniques of construction, and finishes at an appropriate level of durability.
Materials used to make furniture • A variety of materials are used to make furniture, but the primary structure of most furniture is based on three families of materials, used alone, or in combination. • The three families of materials are: • wood • metal • plastics
Wood furniture • Wood is still the most used furniture material, and was almost the only material used in most historic (pre 20th century) furniture. • Wood used for furniture is either: • solid wood • plywood
Solid wood furniture vs. plywood furniture • Solid wood • To produce a board measuring 1 inch thick, a tree is cut down and sawn to random lengths of 6 to 12 feet. • Since trees are round and boards are rectangular, there is substantial waste. • Imagine a square within a circle and everything outside of the square is trashed. • Next, the board desired is rough-cut from the log, and the saw kerf wastes another centimeter down the length of the log every time it makes a board.
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A 1 inch thick board must be rough cut to a little less than 1-1/2 inches thick, then dried, which causes slight warpage. To make the board flat and smooth, it must be planed, this trashes another 3/8 to 1/2 inch. In producing a 1 inch thick board already the waste is greater than the yield. The board is just a random width and length, and the piece of furniture is not even started. If the simplest stick chair is made, waste is another 25-30%, and if a piece of furniture has any curves or uses a low yield species of wood, like cherry or walnut, the waste factor is another 100% to 200%......or more.
• In comparison with solid wood construction of furniture, using plywood is much more efficient as a use of wood. • Furniture grade plywood is manufactured specifically to be used as an exposed, visual, attractive, finished surface. • One type of furniture grade plywood is called ‘Baltic Birch’ plywood. • Baltic Birch plywood is made of 7, or 15, layers of birch, each layer turned 90 degrees from the previous layer. Baltic Birch plywood is made in sheets that are 5’ x 5’. • This yields a piece of plywood that is very stable, visually refined, and without voids in the layers.
Edge of Baltic Birch Plywood 13 ply = 3/4� thick sheet
Birch natural, unstained color
• A good web page showing photos of different types of wood surfaces.
• http://www.boulterplywood.com/ProductGallery_41.ht m
A connection using baltic birch plywood Edges of typical sheets of baltic birch plywood
A table using baltic birch plywood and steel tubes.
A glass top with molded baltic birch plywood base elements.
Metal Furniture • Metals are used to make parts, such as legs, frames, and table bases, and as a primary material for office furniture, kitchen cabinetry, utility shelving, and storage units. • Steel in the form of rods, tubing, and sheets is the most used metal for furniture. • Aluminum in the form of tubes, and formed sections, such as angles, channels, and T’s is used for cast legs, frames, and small parts.
• Metal office furniture and utility files, cabinets, and shelves are made of sheet steel. • The sheets are cut, and then bent to form box shapes, or with bent flanges (edges) used to make shelves or tops. • The gauge (thickness) of the sheet metal is an important factor in determining the quality of a piece. Sheet metal that is too thin will not hold up well. Thicker sheet metal is stronger, will last longer, and will resist denting and deforming.
Plastics used in furniture • Plastic Laminates: are composed of layers of heavy paper impregnated with melamine resin. • Acrylics: such as Plexiglas and Lucite, resemble glass in their transparency, but can be made translucent and colored, and opaque. Acrylics can be bent and molded into curved shapes. • Molded Plastics: such as styrene, polyethylene, nylon, and vinyl, are often made into small parts, such as glides, rollers, edge trim, and drawer pulls. • Fiberglass: a hybrid material in which glass fibers are embedded in a molded polyester resin. Used to make custom auto body parts and small boat hulls.
A molded fiberglass part for an airplane
Making fiberglass objects
Two half molds that will be used to form a fiberglass drum.
Fiberglass chairs using a design from the 1950’s that show the fiberglass fibers.
The Eames' fiberglass reinforced chairs solved the problem of how to make a seat out of a single shell. This chair went into production in 1950.
This chair has a molded fiberglass frame that is made of fireretardant polyurethane foam.
Fiberglass seats designed by Swedish designer Peter Fargring and produced by London based LosPalurdos.
Molded fiberglass
Molded fiberglass chairs
Molded fiberglass chairs
Fabric upholstery over foam on steel frame
Molded foam with fabric upholstery
Fabric upholstery on molded foam with steel rod legs
Molded plastic stadium seats
Steel sheet metal cut out chair
Components of Chairs Office chairs are sophisticated pieces of design and construction
• Chairs need ‘feet’ to ease the friction between the floor and the chair, and to provide a visual and functionally appropriate termination of the legs. • Casters:
Special Needs Chairs often a medical environment necessity
Herman Miller ‘Caper’ chair with casters
Herman Miller ‘Aeron’ chair One of the most sophisticated, and now famous, contemporary office chairs, in comparison with a wood office chair dating from the 1940’s
‘Aeron’ chair designed by Don Chadwick, and Bill Stumpf
• High-performance, long-term seating in three sizes with a full complement of adjustments and innovative suspension • The two designers began this development process with a clean slate, with no assumptions about form or material, but with some strong convictions about what a chair ought to do for a person. • "The human form has no straight lines, it is biomorphic. We designed the chair to be above all biomorphic, or curvilinear, as a metaphor of human form in the visual as well as the tactile sense. There is not one straight line to be found on an Aeron chair.”
Substantial research and testing went into the design of the Aeron chair. • The Aeron design was refined and validated through research and experts' opinions: • It was tested for comfort with scores of users, pitting it against the best work chairs available. • Leading ergonomists, orthopedic specialists, and physical therapists evaluated the chair's fit and motion, the benefit and ease of its adjustments. • The design team conducted anthropometric studies across the country, using a specially developed instrument to calculate everything from popliteal height to forearm length. • The research team did pressure mapping and thermal testing to determine the weight distribution and heat- and moisturedissipating qualities of the Pellicle material on the chair's seat and back.
• The pellicle is a thin layer supporting the cell membrane in various protozoa, protecting them and allowing them to retain their shape. They vary from flexible and elastic to rigid. • thin film or membrane
• "The Pellicle was equally a deliberate design strategy in that its transparency symbolizes the free flow of air to the skin in the same way lace, window screens, and other permeable membranes permit the flow of air or light or moisture. • The transparency of the chair as a visual element was in keeping with the idea of transparent architecture and technology, which Aeron pioneered in advance of Apple's transparent iMac computers. • Transparency is a major design movement. • Its purpose is to make technology less opaque, to communicate the inner workings of things, and to make objects less intrusive in the environment. Aeron is a nonintrusive chair."
The Aeron chair comes in three sizes and a choice of Pellicle weaves and finishes.
Bowling Ball chair made of 15 half bowling balls
• A web page for wheels and casters • Sofa Design Ideas Website