Hi, I'm Chris Jarman from Eliminator
Kustoms here in Goodrich, Michigan. We
kind of specialize in high-end racecars,
street car, metal fabrication and engines.
Today I want to talk to you a little bit
about the proper techniques and
procedures on welding mild steel roll
cages in cars. A lot of times we get
people that try to do it their own or
shops that are unqualified, which is
great but they don't pass certification
and a lot of these cars have to pass
certifications. So what we're going to
talk about is different angles that you
will find in these race cars and that
you need the proper technique to get the
proper weld techniques down. We're going
to go over some joints that we recently
cut out of a customer's car that would
not pass certifications. I'd like to
point out some of the flaws in the
welding process here. Here you can see
the weld is very cold. The fusion is not
in some spots etching into the metal on
both sides. On this joint you actually
have a lot of stop and starts and you
can actually tell the way the weld looks
that there was a huge gap that the
person tried to fill in, which is
something you really don't want. What
you're really trying to achieve is is a
perfect world like this. Great fusion on
both sides, we had good tight joint
preparation which aids in the welding
process to get to this finished product.
For our project today we've chosen the
Millermatic® 212 Auto-Set™. We're going
to be using this to weld one 34 wall DOM
roll cage tubing mild steel. We're
choosing to use the machine in manual
mode because we're going to be making
fine adjustments to our weld and wire
speed due to the angles and notches
typically found in the roll cage
application we're going to be doing.
We're going to be using 0-30 wire. We're
going to be using a 75-25 argon CO2 mix
also in the process. Okay, the first joint
we're going to go over today for with
our tips is the 90 degree joint. First
you want to make sure that you have a
really good fit. This is going to lead to
a good weld joint. The next thing you
want to do is make sure you tack in good
four spots, okay. Usually typically go top
and bottom side to side. If you do that
you'll actually probably depending on
your weld side will actually when you're
welding you'll weld over top of your
tack. We like to weld and actually tack
in the four corners that way we can
actually start and stop at our four tacks.
Okay, we're going to talk to you a bit
about a tip about welding direction. On
this joint actually is thicker tubing. We
actually use the pull method which is
actually pulling the gun towards us, the
MIG gun. What that's doing is it's
actually creating more penetration due
to the weld wire actually going towards
the heat at all time. If you're going to
be using thinner metal what you might
want to do is try the push method,
because what you are doing the wire is
actually transferring towards the cooler
part of the joint, which is creating less
heat for less penetration which will
give you more control and not as much of
a chance to actually blow a hole through
your weld.
Okay, the next joint we're going to talk
about is our 30-degree joint. We've
already got it tacked up. We chose to
tack it on each side and on the bottom
and three points. The reason we're going
to do that is we're going to actually
start in the deepest part of the bevel.
We're going to go down one side. We're
going to come down the other side and
then we're going to finish to weld the
bottom up.
Okay, we finished up our 30-degree joint.
During the process the gun nozzle was
able to get down deep enough in the
joint to actually permit us not changing
the settings on the machine. During this
process we actually use the push method
so we could actually watch the arc and
the puddle as we were actually doing the
weld. Okay, we're going to go on to our
last joint here which is our 45 degree.
You can tell the joint is much deeper.
We've gone ahead and tacked it up. The
one thing I want to show you is a little
tip. We are going to be adjusting the
machine now. We're going to be turning it
up just a little bit; the heat. Reason
being is the wire is sticking out of the
nozzle a little bit farther because we
cannot get the MIG gun tip down in the
joint as far as such on a 30 degree
angle. What happens is we're going to
turn up the machine to promote the wire
burning off hotter in this joint because
it's sticking out longer so we can get
better penetration in the weld.
Today we showed you a lot of typical
joints that you're going to find on
common roll cage construction. One of the
highlights that we pointed out was your
actual MIG gun nozzle placement in the
joint as you're welding. Another good tip
to remember is depending on your
material thickness whether you want to
use the pull or drag method or the push
away from your method. The drag method
towards you will promote more
penetration and more heat for thicker
metals. If you're joining the weld center
metals, you might want to try the push
method because it directs the heat away
from the weld with less penetration to
prevent you from blowing through your
material for getting the weld too hot.
For more racing, customizing, and
restoring tips go to MillerWelds.com.
