DISCLAIMER: I'm not a pro, I still have lots of learning to do! These things helped me improve, but doesn't mean they're necessarily right or will help you.
It was a good day of tig-welding practice yesterday. The tubing pictured here isn’t bike frame tubing, it’s the same 0.9mm x 1″ diameter straight gauge 4130 tubing from Aircraft Spruce (AS) that I have been using for practice. (I may use it for straight blade/gauge segmented forks though someday soon.) Every day seems to produce different results depending on how tired I am, how much time I decide to spend filing and cleaning the tubes, and so on. Anytime when I have learned something new, whether it be telemark skiing or how to ride a certain stretch of technical trail, I tend to over think doing that thing while trying to do it – looking where I don’t want to go – and messing up because of that. Too many things, too much advice swirling around in my head while thinking that I’m trying to focus on the task at hand. But like most things, the less you consciously think about that task, and the more you just let your body DO the task, the better it turns out. I’m not there yet with getting in the welding ‘zone’ or whatever you want to call it, but I can tell that i’m loosening up a bit. I’m not gripping the torch so tightly and I’m breathing easier while welding, and moving the torch more quickly and smoothly along the joint.
I’m by no means ‘there’ yet with the welds. As the pro’s will see any even read this blog, I am still not moving quick enough and/or using too much heat so overheating is still occurring to a certain extent. But some of that is not the weld and just the darker color of the tubes from AS (and the fact I’m not polishing the tubes in these pics before or after welding). This joint is first pass, non-pulsed, just moving the torch and dipping the rod into the puddle…plain ole tig welding.
So, the tips that have helped me the most (this one goes to 11):
- Finish filing the cope/mitre with a Smooth or 2nd Cut file (not a Bastard), and then smooth out with a higher grit emory cloth. People have recommended 80-100 grit but I like an even higher grit than that. Use the emory cloth inside and out of the tube. Blow out the scale on the tube with an air compressor gun.
- After filing, deburring, emory cloth’ing: Clean the tubes you’ll be welding more than you think you need to. So that you you eat a meal using the tube as a spoon. I use Simple Green and then water, and then SG again, and then water, inside AND out. Blow out any moisture or extra scale with the compressor. Some use more toxic cleaning agents, but my house is on a septic system so i don’t want to use that nasty stuff…for more reason than one.
- Overestimate the amperage you need to weld the joints by 5-10 amps, based on personal experience and tubing thicknesses. Make mistakes (on practice tubes of course) so you know how hot is TOO hot.
- Slowly depress the footpedal to heat up the metal and to not blow through the tubes, once you get a good puddle going start moving the torch along the joint at a ‘not-too-slow’ pace (not sure how to describe the pace…).
- Once done with 1/4 the circumference of the tube, SLOWLY back off the heat to prevent any ‘volcanoes’ or craters from forming. Leave the torch there, not moving, for the gas purge time (~12 seconds).
- Breathe. Make a conscious effort to breath while welding. It sounds stupid, and maybe nobody else does this but me, but I noticed that I was holding my breath to stay more still while moving along the tube. Not good.
- Learn to rotate the torch in your hand along the joint while welding to keep the proper torch/tube angle, and learn to move your head to stay in close sight of the puddle at all times.
- It’s ok to pause and restart if you can’t see the joint and puddle well enough. Better to have the correct angle and see the puddle as best as possible than blow through a tube or not get enough weld penetration.
- Find something to rest/steady your hands on, both hands. I like to use tubing blocks.
- Visualize the process before you start. Practice the movement, without striking the arc, with both torch and rod hands, making sure you can move along the entire length of the joint without any obstructions – visually or physically (i.e.,, tube gets in the way of your view, or the gas lens cone hits the tube, etc). It’s surprising how much this helps. I thought all was good until I tried doing this and had to re-position my workpiece or torch or both.
- Practice, practice, practice, practice…to..infinity. One tube joint every day if you can. Like any training, if you lose a week of welding, your welding ‘fitness’ deteriorates, at least when just starting out.
These tips probably sound obvious to most welders, but I used to try to weld 0.035″ tubing at 32 amps by flooring the footpedal, and although I’d get a puddle going, i’d end up blowing through tubes more frequently than with using more heat (not very intuitive, eh?) because I’d stay put too long trying to get the puddle to form and keep it moving. I like the results I get better when going a bit hotter than that (42-46amps for 0.035″ thickness tubing) and backing off a bit once the puddle forms and moving faster along the joint dipping the rod to cool the puddle. The area of heat affected zone is narrower (seen as the space between the blue and the bead), and you get no (or less, in my case) of that gray matte crusty looking area immediately adjacent to the weld that indicates too much heat.