Posted by Joe Lorenzino on October 28, 1998 at 23:12:03:
In Reply to: Re: Mig & Plasma cutter question? posted by AL on October 28, 1998 at 21:46:58:
My thoughts on mig's and plazma's. I too own a welding shop where we have a variety of
welders of all brands. As stated above, Service/parts is Very important. We have found in
our shop, that some of the older equipment is far superior to the "newer, better,
faster....etc." model that replaces it, so getting a used machine might be an option. I
personally prefer Miller machines. They seem to be smoother and easier to set than the
others(Lincoln, Esab, Hobart) that we have. Miller also makes machines for many other
"suppliers", so sometimes the same parts can be had from several sources instead of just
one. (This also lets you "comparison shop" for price very easily) It sounds like you
already have a stick welder, and that the mig will only be for bodywork/sheetmetal. In
that case, a 110v mig is just the ticket!! We keep one here at the shop just for those
things that are TOO THIN to weld with the big machines. BUT........ IT WILL NOT
PROPERLY WELD ANYTHING THICKER THAN 1/8"......... If you get a mig welder,
BE SURE to get the gas solenoid and a flow meter that fits a STANDARD SIZED gas
cylinder.(not the tiny "propane canister" size) Many manufacturers DO NOT include
these in the "base model" machines, and without them, you can only use flux-core wires.
(messy for body work, but a little bit "rust tolerant", solid wire with gas shield does a
much nicer job IF things are clean) Also make sure to get one that has "infinite controls"
for BOTH wire speed AND voltage, as the add greatly to the control of the machine.
Watch for the duty cycle, and the NEMA class rating. The lower the duty cycle, the more
time you will spend cursing and having coffee while you wait for the machine to cool
down again.( Duty cycles are rated as a % of time on in 10 minutes ... 20% means an
8min. coffee break every 2min. of welding AT THE RATED OUTPUT {longer when
using lower settings}) Make sure the ratings are in the same NEMA class (1 = rated @
60% duty, 2 = rated @40% duty), although some of the small units seem to be rated at
their maximum output, with the duty in fine print behind.
As for a plasma, get the biggest you can afford. Again, there may be some good
used equipment available as others change up to larger models. We are on our 3rd.
machine as purely a factor of capacity. Again, keep the parts/service thing in mind, and
the "consummables" as well. There are aftermarket suppliers for the consummables, that
are usually less expensive, so again it pays to shop around. Plazma's are faster than a
torch TO A POINT, after which, any thicker is more efficiently cut with oxy-fuel. That
point is typically about 1/3 to 1/2 of the machines rated capacity.( ours Will cut 1 1/4"
plate, but we switch to the torch at1/2" or better) Check to see if the machine is a
"contact"(must touch the workpiece to function) or a "stand off"(doesn't have to touch,
and can be used for more things) type. If it is a stand off, does it have a guard/holder that
HAS to be there for use( these "guides" tend to get burnt up Real Quick, and are way
more expensive than they look) If you don't have a torch, I would suggest buying one of
them first, as it is much more versatile than a plazma which can only cut.
And remember, any kind of machine is only as good as the operator, and the
condition of the material it is to be used on. They do not to my knowledge make any kind
of welder that melts metal, dirt, rust, grease, and paint together into anything that could
be called a good weld. CLEAN IT FIRST!!!!!!!! J.V.L.