"Gunner Asch" wrote in message
...
On Sun, 04 Sep 2005 15:36:28 GMT, "Gary H. Lucas"
wrote:

for torturing the cat." Gunner

Gunner,
Are you Mig welding aluminum? If so I can give some useful hints. There
are a couple of things that will tell you if you are doing it right.

Great tips! Saved for the near future. Right now Im TIG welding
alum.
But thanks again, and when I get my MIG issues squared away, Ill
damned sure try em.

Gunner

"Pax Americana is a philosophy. Hardly an empire.
Making sure other people play nice and dont kill each other (and us)
off in job lots is hardly empire building, particularly when you give
them self determination under "play nice" rules.

Think of it as having your older brother knock the **** out of you
for torturing the cat." Gunner

Ah, Tig welding, my favorite process. You have so much control that it is
amazing what you can do. I have some helpful hints here too.

First, shield yourself and any helper very well from the light. I once had
a small burn hole in my shirt where my belly button is and got a 3rd degree
sunburn there! A guy asked me to weld up a set of headers for him, he held
the parts in place. He just turned his head to the side. His face and eyes
were so badly burned he was out of work for two weeks. Even though I WARNED
him over and over!

Aluminum requires tons of power to weld, because it is such a good heat
conductor. I used to repair aluminum light pole bases and even aluminum
bender shoes for contractors. These are real thick and a 250 amp machine is
a joke. I used a plumbers propane pot heater to preheat the parts. When
solder would melt when touched to the surface the temperature is about
right.

It is real easy to burn through when welding aluminum. Aluminum isn't like
steel which turns red, get brighter and brighter, and then finally sags
through. Aluminum is there, and then it ain't. The thing to remember is
that you have two sources of heat control when Tig welding. The welding
current, real nice if you have a control on the torch or foot pedal, and the
filler rod. Dipping the filler rod in the puddle cools the puddle and
solidifies it. So if you get a hole you feed the filler rod as fast as you
can and fill it right up. I find that wearing a light cotton glove on the
hand holding the filler wire instead of a welding glove gives you much
better control of the rod. Just don't leave any skin showing or you WILL be
sorry!

The filler wire should be kept close to the arc but not close enough to
melt. Because it is hot it will melt into the puddle very smoothly. A cold
rod may freeze in the puddle then burn off, and this can contaminate the
weld. Keeping it close also keeps it in the shielding gas, which helps
reduce contamination.

Note that filler wires are seldom the same allow as the alloy you are
welding. For instance 4047 is very popular for 6000 series aluminum.
Someone once asked me to weld the broken generator bracket on a VW block. I
welded it with 4047 and it looked beautiful. About 5 minutes later when it
cooled we heard a pop and the weld fell on the floor! He had another broken
mount so I ran it through the bandsaw and cut some crude filler rods. That
worked great and the weld worked very well.

Have fun.

Gary H. Lucas