The advantages of having gas on you welder go beyond allowing use on
aluminum.
When you use a torch to cut steel, you actually "burn" the metal. The
oxygen reacts with the metal and it dissapears. In fact, once you start
cutting, you can actually turn the gas off and the straight oxygen will
support the cutting process.
When you "burn" a hole through a thin section you are welding, you are
doing the same thing. A MIG (metal inert gas) welder floods the area with
a non-burning gas- usually nitrogen, argon, or helium- and retards this
process. So you can use more heat on thinner metals and not burn through.
Gas also limits the amount of slag that build up around the weld. This
allows you to see your weld pool more clearly and makes it easier to
control the weld. It also makes cleanup easier.
Someone mentioned practicing on scrap metal with a wire feed (non-gas)
welder. Although I have never used a wirefeed welder without gas, I
wouldn't thind that it would be much easier to use than a standard arc
welder, in my opinion. If you use the right welding rod, a DC arc welder
can weld fairly thin material. The issue is with welding thin material is
getting enough heat without burining through.
When welding thin sections, I would rate the following as the most
important to the least important. This is assuming that the welder can be
adjusted to put out the proper amount of energy.
1) Electrode diameter. The smaller the welding rod or wire, the thinner
the material you can weld. Wirefeeds by nature use very small electrodes.
You can also get very thin welding rods for standard arc welders.
2) Cover material- by this I mean gas or flux. Inert gas is by far the
best. Argon is great. Helium is good but can cause embrittlement in some
materials such as titanium (probably not an issue on most LBC's). Nitrogen
or mixtures are acceptable for most welding situations.
3) Welder quality- Two issues here. A good welder better controls the
power output, gas flow, wire speed, etc. Second, a good welder will use DC
current instead of AC. This allows you to start and maintain an arc at a
lower power setting than an AC welder. Also, some people claim that
certain DC polarities work better in certain welding situations but I don't
know for sure.
4) Rod or wire material- There are more types of welding rods than Carter
has pills. There are different rods for welding vertically compared to
welding horizontally. I leave this last because we are talking about wire
feed or arc welding of relatively thin steel sections. Most of the time,
you would be using a multi-purpose rod or wire. However, if you are
planning to weld cast iron or aluminum, then material selection would be
very important.
I am not a professional welder but I have spent a lot of time in a machine
shop and have laid down more than my share of beads. As alway, my
opinions, YMMV, yada yada yada.
Regards
Bill Eastman
61 MGA patiently shivering in the garage awaiting Springtime on the tundra.
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