Presentation on theme: "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."— Presentation transcript:
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 leaves- Oak, 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