TIG welding (by alaric)
Back in 2008, I took a welding course, in which I fixed the mistake I was making with my stick welding, and had a go at MIG and TIG.
Now, although I learnt to make nice beads with stick welding on flat surfaces, I still struggle with various things. Much of the welding I want to do is on thin metal, so I need to run the welder at a very low current, creating a feeble arc and with a tendency to stick, and still burning through if I'm not quick. I still can't do inside joint welds (the arc sticks to one side, or the other, and rarely both).
Is it my poor technique, or am I being limited by the fact I'm using a ten-year-old arc welder that cost £50 from B&Q? When I borrow a friend's MIG welder, I do much better work, and tinkering with my technique over the past decade has failed to make a huge improvement...
Whether it's me or the welder, I know that stick welding isn't perfect for what I want to do. As well as the issue with thin materials, it can't weld aluminium. I had a stick welder because it was all I could afford at the time, and living in a small flat, I didn't want to be storing compressed gas cylinders!
TIG is widely regarded as hard to learn, because there's so many variables to control - those ten complicated-looking knobs on the welder, the movement of the torch, the fine control of current with a foot pedal, the way you feed the filler metal in. However, when I tried it, I found that I liked all that control. With a MIG, you set the power level and the wire feed speed on the machine, and then pull the trigger to weld - which is great if the settings are all correct and you're doing a long straight uniform bead. But if you're having to change position as you weld, or dealing with varying thickness of metal so the rate of conduction away from the weld varies, it's trickier to have those settings correct. And to get them right, you need to do test welds, adjust, and do more test welds.
With a TIG welder, you can vary the speed at which you move the torch (and the current, with a pedal) and the rate you dab filler metal as you work, based on feedback from how the weld looks. Although there's more to vary, there's less need for trial and error. That suits me better! Back when I did the welding course, I'd really enjoyed TIG, and found it easy to do great welds, but a MIG machine looked a lot more likely to be affordable. So I was slowly saving up for a MIG machine.
And then I found that R-Tech, a local company on the outskirts of Gloucester that make welders and are widely lauded for their quality and good customer service, offered twelve months' interest free credit.
Suddenly, rather than saving up for many months for a MIG welder, I could afford a TIG welder (and quite a good one, too), with the money I'd saved as a deposit and then sixty pounds a month for the next year. THIS CHANGES THINGS...
So, today, my new TIG welder arrived. It can go up to 160 amps, it can do AC or DC (so it can be used for aluminium), it can do pulsed power control, and it has a foot pedal for precise work. So it'll be great for thin stuff. Also, it can do stick welding, but "nicely"; DC, with good current regulation, as opposed to my old AC transformer. That should make it produce much more steady arcs, so I'm looking forward to seeing if I can also improve my stick welding with it - stick welding is worse than TIG in most respects, except that it's faster and doesn't use up shielding gas. I still have a lot of stick welding electrodes to use up, so when I'm doing work on heavier bits of metal, it'd be nice to use them if I can do so and still produce good welds!
This evening, I unpacked it, ground a tungsten, put everything together, and rearranged some shelves in the workshop to set it up. I made a hook to hang the torch on by my welding bench, checked that the right things appear on the display when I turn it on, and then sadly bade it goodnight, as I'm not getting the shielding gas cylinder for it until tomorrow.
My plan is to start running test beads along a bit of scrap steel until I seem to have got the hang of it, then do a few easy jobs - such as re-doing some of the shoddy welds I messed up with the stick welder, and adding a steering stop to the festival trolley, and fixing a bit of my welding bench that snapped off after the bottom rusted.
Once I'm confident, I'm going to finish my current big project - a custom server case for love.warhead.org.uk, which hosts this site and many others! I've been taking it to my friend's workshop to use his MIG on it, which only happens when we're both free (less than once a month), and involves folding all the seats down in the car and lugging a significant weight of steel through the house. Did I mention that this thing's 1.2 meters high, and made of 1.6mm thick steel plate?
But I'm so incredibly stoked I'm going to have a TIG welder. I'd all but given up on the dream!
Alaric, Metalworking | alaric | 
Tue 21st Jul 2015 10:17 pm
Subscribe