Building materials-- WOOD

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Building materials-- WOOD
Wood grows on trees. But the kind of trees
determines the kind of wood. There are two basic
types- hard wood and soft wood.
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In North America the difference between hard and
soft wood is leaves. Hard wood comes from trees
with leaves- Oak, maple, poplar, cherry, walnut,
etc.In theatrical construction we dont like
hardwood, its heavy, dense and difficult to work
with. But most importantly- its EXPENSIVE!
Hardwood is great for furniture you want to last
for years. On stage we just need to make it look
like its made to last for years.
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Soft wood comes from trees with needles- pine,
spruce, cedar, redwood, cypress. These trees
grow faster and provide most of the lumber
available for building. It is less dense,
lighter, and easier to work with.
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We are going to break wood down into two
categories. First lets discuss- Stick lumber
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Stick lumber always comes in even lengths.
Standard lengths are 8, 10, 12, 14, and 16.
Lumber is priced by the board foot, so a lumber
order just involves the total amount of linear
feet we need. Long clean pieces of lumber are
usually more money.
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Sizes of stick lumber
Most lumber sold today is milled lumber. This
means they have sanded the wood so it is smoother
and doesnt have as many splinters. But some
thickness is lost in this process. This gets us
into the difference between nominal and
actual size. Nominal size is the name of the
size of wood, like 2 by 4. The actual size of a
2 by 4 is 1 1/2 inches by 3 1/2
inches. There are two principal sizes that we
will talk about. Most of the lumber sold today
in America is made into these sizes. They are -
1 by and 2 by.
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2 by
1 by
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1 by
Lumber that is nominally called 1 by is actually
3/4 of an inch thick. We usually order 1 by 12
(3/4 x 11 1/4) and rip it down to the the width
we need with the table saw. The sizes you will
most often encounter in theatre carpentry are 1
by 3 (used to frame stage flats) and 1 by 6 (used
to frame platforms.
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2 by
This kind of lumber is actually 1 1/2 thick.
Its exactly twice the thickness of 1 by. The
most common size is the 2x4 (1 1/2 x 3 1/2).
But 2 by comes in many sizes- 2x2, 2x6, 2x8,
2x12 This is heavier lumber usually used for
platforms or structures that will remain in use
for a long time.
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Ruff cut
Lumber that has not been milled is called rough
cut or barnwood. This lumber is usually not
available at Lowes and Home Depot but you can
find it at a lumber yard or farm supply store.
In Theatre we use this stuff when the design of
the show calls for it.
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Pressure treated lumber

• This is wood that has been treated with inorganic
  arsenic (poison) to preserve the wood from
  insects and rotting. PT wood is meant to be used
  outdoors, in contact with the ground where
  untreated wood would rot within a year. We dont
  like this in the theatre for several reasons.
• It is heavier that untreated wood.
• It is more expensive than untreated wood.
• It takes paint differently than untreated wood.
• It releases toxic arsenic into the air when
  cut with a saw.

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Sheet lumber

• When we have used stick lumber to make a frame we
  use sheet material to cover the frame. There are
  several types of sheet materials used for
  different situations.
• All sheet material comes in the standard size of
  4 feet by 8 feet.

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Plywood

• Plywood is created by gluing several layers (or
  plys ) of wood together to create a strong sheet
  of wood. Trees are essentially peeled to make
  thin sheets of wood. These are then glued
  together with the grain changing direction with
  each layer.
• Plywood is made in correctly labeled sizes,
  unlike stick wood. 3/4 plywood is 3/4 thick.
• The grading system for plywood uses two letters (
  one for each side). Plywood that has one very
  good side and one mediocre side is called AC. We
  usually order the cheapest stuff- CD.

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Aspenite

• This is a wood product made from what is
  considered waste wood. It looks like wood
  shavings glued together into a sheet. This stuff
  is cheap and comes in the standard sizes and
  thicknesses. The glue can smell a little funny
  when being cut with a saw. Aspenite has one
  major disadvantage- it tends to fall apart when
  it gets wet.

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Particle board

• Particle board looks like aspenite made from
  sawdust. It is very cheap but is much heavier
  than plywood of the same size. This is the stuff
  that is used in Mica furniture. It is made very
  flat and takes the Formica veneer very well.
  Unfortunately when there is a break in the
  material is cant be repaired or reglued.
  Particle board also falls apart in water.

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Luan

• Luan is a thin material somewhat like plywood but
  the surfaces are a much better finish. This is
  unfortunately made from rainforests. There are
  some companies trying to produce Luan from farmed
  trees or sustainable sources.
• We use this stuff a lot. Its cheap and light and
  strong and has a great surface for painting.
  Most of the wall flats in theatre is made with
  Luan these days. This is usually found in 1/4
  and 1/8 thickness only.

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Masonite/ pegboard

• This is thin sheet material that is used for
  flooring. The platforms that are made from
  plywood are then covered with masonite to give a
  hard smooth surface for painting, walking,
  dancing. Masonite comes in 1/4 and 1/8
  thickness, and in tempered and untempered
  finishes (tempered is harder and doesnt warp in
  high humidity).
• Pegboard is masonite with holes every square
  inch. It is used to organize and hang things.

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Veneer

• In Theatre we are mostly concerned with
  appearances. The audience will be seeing the
  show from a distance and as long as things look
  correct from that distance we can get away with a
  lot up close. Veneer is a thin sheet of wood or
  Formica that is glued onto another material. A
  desk made from particle board that is covered
  with an oak veneer will look like an oak desk.
  Some of the furniture in your house may have
  veneer on it.

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MDF

• Medium Density Fiberboard is a new engineered
  wood product that can be considered super
  particle board. The board is made from very
  small particles and is strong and can be cut into
  very detailed shapes.

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This is an introduction to wood. We will cover
how to use this material to create things for the
theatre in the weeks to come