I have the honor of teaching at the NuVu school in Cambridge for ten days starting next week: young students are going to make rolling musical instruments out of bicycles. I’m excited to see what thy come up with. But before we begin, I must learn how to weld all over again.
Welding is any process where two or more separate pieces of the same metal material are melted together to become one. Typically a filler wire is added to compensate for the inherent deficit. There’s also a shielding gas to keep the atmosphere away from the molten metal. While there are many methods of welding, the four most common techniques are arc (or stick), gas, MIG and TIG. The the method I use is TIG, which stands for tungsten inert gas.
TIG welding uses a torch with a non-consumable tungsten electrode to create an arc hot enough to melt the material. This electrode is held one millimeter away from the piece as it methodically travels along the seam. A filler wire is added with the non-torch hand, as inert gas from the torch displaces the atmosphere around the weld zone. A foot pedal is used to regulate the power of the arc. Torch speed, angle, and distance from the base metal — as well as wire angle and deposit rate — are all important factors, which makes learning the Way of TIG very difficult. However with lots of practice, lots of patience and a good teacher; you can learn make some very beautiful weld joints.
3-2.5 Titanium, 1 1/4″ diameter, .038″ wall. I learned to weld on titanium like this before moving onto steel, copper, bronze, and eventually aluminum.
Needless to say, the class cannot devote that kind of time to learning to make these ‘stacks of dimes’. Fortunately there a far easier way to weld: behold the hot glue gun of the weld world: MIG.
My first MIG welds: 4130 chromoly, 1 1/4″ diameter, .058″ wall. Tube coping by Lucas.
MIG welding has a spool of wire that is push-fed through the torch cable, and acts as filler and electrode all in one. It’s a simple, one-handed operation: set your machine, point and shoot.
Until last night, I never learned to MIG, and always shied away from it, mostly because I thought it was funny that I never picked it up. Most people learn MIG first, then move onto TIG. In retrospect I may have become a better welder if I had tried it earlier. The more empathy with the metal, the better.
I watched some videos and read some booklets. I talked with a few MIG welders. Then I gave it a shot. I have to say, it was a lot of fun! I felt like a ballet dancer in a mosh pit.
Getting the settings correct is more important than with TIG, since they cannot be changed on the fly. There’s more smoke and spatter, but far less than I had imagined. MIG welding is quick like a bunny. Best of all, it’s pretty easy to learn.
As I was welding along, remembering to keep my ‘stick out’ and ‘push angle’ correct as I swirled the puddle around and moved along the seam, I remembered the mosh pits I used to dance in at the University of Orono Maine. It was a lot of fun bouncing around and flailing: it was chaos, but with some strict rules. You dance in such a way that you pay attention to the others in the pit so that no one gets hurt. And if you lose control and fall on the ground, you are picked up by the crowd so fast you almost don’t have time to realize you went down in the first place.
MIG and Moxie: a winning combination.
I asked to borrow a MIG welder for this class in an email to the discuss list at the Artisan’s Asylum where I make, play, and teach. I thought it was a tall order, borrowing such a useful piece of equipment for two weeks. But like the mosh pit, my friends helped me out faster than I imagined. Within an hour of the request I had six offers. Like the mosh pits, we are really looking out for each other at the Asylum.
While I have more practicing to do, I am happy with my glue gun welding so far. They say that teaching is learning twice, but I intend to learn more than twice during my time at NuVu.