Transcript Furniture Structure and Materials

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
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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
• http://www.muvtons.com/products.html