Transcript Building materials-

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.
In North America the difference between hard and soft
wood is leaves. Hard wood comes from trees with leavesOak, maple, poplar, cherry, walnut, etc….
In theatrical construction we don’t 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.
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.
We are going to break wood down into two
categories. First lets discuss-
Stick lumber
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.
Sizes of stick lumber
Most lumber sold today is ‘milled’ lumber. This means
they have sanded the wood so it is smoother and
doesn’t 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.
1 by
2 by
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.
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.
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.
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 don’t 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.
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.
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.
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.
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 can’t be repaired or reglued. Particle
board also falls apart in water.
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.
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 doesn’t warp in high humidity).
Pegboard is masonite with holes every square inch. It is used to
organize and hang things.
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.
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.
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