Transcript STEEL - Osceola County School For The Arts

STEEL
Steel is a combination of iron and carbon.
There are different formulations of steel
for various uses. There is stainless steel
used for forks and spoons, and tool steel
used for scissors and screwdrivers.
Steel formulations are made to different
strengths and rigidity. Steel that is made
very rigid (like tool steel), will break
before it bends. The steel we usually
build with is soft steel called A36. Very
much like play dough this steel can be
formed into any shape depending on the
mold you push it through. Because all
the shapes are the same formula of steel
we can weld them together.
Steel is a material that is harder than wood
to work with but it has its uses. When we
need to have a lot of structural strength in
a small space we use steel. The same
strength in wood would take up much
more space. Another use is something
that is going to be used for a long time,
such as on a tour, and needs to take a lot
of abuse. Steel has that durability but it
also has weight.
Shapes
The more common shapes of
steel building material are I T
L C box tube, bar, rod/ dowel
and pipe
The shapes are sized depending
on the actual size of the steel.
A rectangular bar has two
sizes- the width and
thickness. An angle (L) will
have three- width of one leg,
width of the other leg, and
thickness. Box tube, I, T, C
will also have three
measurements.
Pipe
Pipe is usually purchased from
plumbing companies and has
different descriptions. Pipe is
specified by its interior diameter
(plumbers care about how much
water can go through), and the
thickness of the walls called
‘schedule’. The pipe we usually
use in theatre (all the flying
pipes) is 1 ½” Schedule 40 pipe.
Pipe often has threads cut into the
ends so you can screw the pipes
together with various
connectors. This allows anyone
with money but no shop
facilities to build things with
steel.
Steel can also be used in sheets. Unlike wood these
sheets come in a variety of sizes. They also
come in various coatings. Basic plain steel is called
‘cold rolled’. Steel that has been given a zinc
coating to prevent rust is called ‘galvanized’.
Sheets come in various thicknesses called ‘gauge’.
A sheet that is 8 gauge is very thick, aluminum foil is
about 64 gauge.
Wire and wire mesh
Wire is also described in gauge. In theatre we often use 16 gauge
black wire (basic A36 steel wire) to secure props and for an
unlimited number of special circumstances.
There are other metals that are
commonly available in wire
form. These are also sized by
gauge and are used for prop
and decorative uses on stage.
Wire is also made into wire
mesh for various uses.
The kinds that we tend to
use in theater are-
Wire Mesh
Hardware cloth -sometimes called rabbit wire, square holes, ½”
and ¼” are the usual sizes.
Chicken wire- used for poultry, hexagonal holes, great for forming
irregular shapes
Expanded steel mesh- this is heavy duty material, diamond
shaped holes, used for platforms and surfaces that have to
support weight but allow light through.
Welded wire- this is inexpensive fencing with rectangular holes.
Aluminum
Steel has one major flaw- it rusts. Steel that is
galvanized to prevent rust is difficult to weld
and paint.
We have another
option for metal
construction in the
entertainment
industry- Aluminum.
Aluminum doesn’t
rust, its lighter, and
the material comes in
the same sizes and
shapes as steel.
Aluminum for Touring
When building things for tours weight is a serious consideration. The
cost of transporting steel truss is more than the added cost of
building with aluminum in the first place. This is why most all touring
trusses and structure is aluminum.
Steel construction
Here are some ways that steel is used in building (theatre and
otherwise).
Steel rebar and wire mesh are used to create the structure for natural
shapes made out of concrete.
Steel channel is used extensively to replace 2x4 studs in construction.
This is cost effective and fire proof. This method of building is
becoming more common in the entertainment industry.
There are other metals we can use in theatre. We can use
almost anything (if the budget allows) should the show
require it. If the material is too expensive we can always
fake it.
Copper wire and tubing, and various brass parts are
commonly available.
Welding and Metal Cutting
In order to make
steel structures
we need to cut
the steel to length
and attach the
pieces of steel
together to create
solid frames.
Metal
Chop
Saw
The metal
chop saw
uses an
abrasion
blade that
grinds its
way through
the steel.
The blade
gets smaller
with every
cut and
eventually
needs to be
replaced.
Band
Saw
The band saw
has a
continuous
blade of small
metal cutting
teeth that cuts
using its own
weight to
press down.
Oxy Acetylene Welding
This kind of
welding uses
two gasses
(oxygen and
acetylene). The
acetylene burns
easily and the
oxygen is added
to make the
flame burn very
hot. This is
then used to
melt the steel.
When
welding in
this method
you need to
set the two
gasses to
achieve a
very hot
flame and
then use
your other
hand to add
steel into
the weld
using a
separate
rod of
special
metal.
Oxy-acetylene
welding rigs can also
be used to cut
through very thick
steel in difficult
patterns. This is their
usual use in
theatrical shops.
Arc Welding
Arc welders
use electricity
to melt steel.
They create a
high voltage
circuit of
electricity
using the
grounding clip
attached to
some point on
the material
and an arc
welding
electrode rod
at the other
end.
MIG Welding
(Metal Inert Gas)
The MIG welder is also an
electric welder that uses
an arc of current. The
difference is that the mig
uses a roll of wire that is
fed through the welding
gun continuously instead
of an electrode rod. It also
uses inert gas (carbon
dioxide or argon) blown
through the welding gun to
push the oxygen in the air
away from the weld.
This is a
MIG unit
with the
gas
canister
attached.
links
http://www.admiralsteel.com/products/steel_products.html