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Welding Aluminum
By Blake Flournoy
Arc welding has been
historically important to construction since its common adoption in the 19th
century.
Today, it is a crucial
component of the fabrication of both buildings and vehicles.
Steel is most commonly used
for welding tasks, but certain situations call for aluminum, which is notably
more difficult to work with than steel.
However, with the right
approach and planning, you can do aluminum arc welding easily, whether the task
is at a work site or in a hobbyist's workshop.
TL; DR (Too Long; Didn't Read)
Aluminum's properties make
it a more difficult metal to weld than steel: It expands more in response to
heat, and its lower melting temperature makes it significantly easier to melt
an entire piece of metal during the welding process.
However, if you do the weld
with attention and at the correct speed and temperature, aluminum can be arc
welded through either the heliarc or stick welding methods.
Be incredibly careful
when arc welding, and never look at an arc without eye
shielding.
Arc Welding Basics
Though developments in
technology over the last century have allowed for the creation of automatic
welders and more efficient welding machines, the basic process of arc welding
has remained the same.
Arc welding is a process of
fusing two pieces of metal together through the use of an electric arc, which
creates an intense heat capable of melting the metal parts.
When melted with a specially
coated electrode, the molten metal is mixed with a filler that binds the two
parts into a single unit.
Various methods of arc
welding exist, based on the techniques and materials involved in the process.
Aluminum Troubles
Steel is often considered
the 'default' metal to use during welding, and in comparison, aluminum is a
notoriously difficult metal to bind with an arc welder.
As an active metal with a
tendency to form oxides, it is harder to create a binding filler suitable for
welding aluminum.
When combined with the
metal's high heat conductivity and low melting point, it is very easy for a
novice welder to completely melt the aluminum pieces involved in the process.
As a result, the first step
to arc welding aluminum is to clean the base metal of any oxides or solvent
oils. The second step is to be mindful of your approach.
Stick Welding
Shielded metal arc welding
(SMAW), informally known as stick welding, is one of the older forms of arc
welding.
Inexpensive and easy to
perform in a wide variety of environments, this welding technique is often
reserved for small fabrication shops and hobby welders but can be used to weld
aluminum together smoothly.
The key is to use a more
powerful, direct current welder and an aluminum-coated electrode.
By welding quickly, without
giving the metal too much contact with the arc, the aluminum can be bound
quickly.
Heliarc Welding
Gas metal arc welding
(GMAW), informally called Heliarc welding, is a process of welding that adds
inert gas, such as argon or helium, in order to ensure that oxidation does not
occur during the melting process.
To weld aluminum with this
method, it is best to preheat the metal to no more than 230 degrees Fahrenheit
before beginning the weld.
By using argon gas and
pushing rather than pulling the welding gun away from the weld puddle, aluminum
can be bound without much trouble.
Blake
Flournoy is a writer, reporter, and
researcher based out of Baltimore, MD. Working independently and alongside
professors at Goucher College, they have produced and taught a number of
educational programs and workshops for high school and college students in the
Baltimore area, finding new ways to connect students to biology, psychology,
and statistics. They have never seen Seinfeld and are deathly scared of wasps.
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