Is pulsing a must-know technique that you must learn as soon as possible? Or is it an esoteric indulgence to be deferred until you’ve perfected basic TIG skills? We often get asked what pulsing is and how important it is. In this week’s Welding Talk, you’ll find our honest thoughts on whether to pulse or not…
When you pulse weld with TIG, you output a pulsed waveform, alternating between base and pulse currents, instead of steady current. This enables you to set a welding rhythm and work to it. Or match pulsing to your ‘dip-move-dip-move’ technique as the weld zone travels. Done well, setting up that rhythm is capable of delivering high-quality TIG welding. But, and it’s an important ‘but’, it’s a very advanced technique. From the start, we’ve got to say that there’s no shame in putting pulsing off until you’re really confident with all the basic TIG skills.
The advantages of pulse welding
The specific advantages of pulsing include achieving a given weld penetration with less power and heat – thus avoiding metal deformation, particularly with thin sheet metal. Another benefit in production environments is improved productivity by optimising the welding to your machine’s working duty cycle rating. Add the easier creation of uniform reliable welds, visually appealing ‘stack of coin’ welds; and reworking unsightly old welds, and you have an unarguably valuable TIG skill. However, as we say so often, it’s not one that most welders should expect – or even try – to master early in their TIG career.
Although you can pulse weld aluminium, it’s more usually associated with steel – particular stainless steel where work-piece overheating can so easily undermine weld integrity and appearance. As such, pulse welding sits alongside another advanced technique, gas purging.
Pulsing is notoriously challenging
Pulse welding is undoubtedly a powerful TIG technique and a great skill to have. But – and we’ll say it again – this is a notoriously challenging advanced welding technique. We often talk with novice welders who think they’ve failed at TIG because they can’t pulse weld. Our response is not to worry. Instead, we counsel that they should focus instead on perfecting good basic TIG technique – and look forward to adding pulse welding later.
Of course, at higher levels of commercial production welding, pulsing is important; but for most amateurs and many commercial welders, it’s simply not essential; in our experience, many superb TIG welders can’t pulse weld! Of course it’s good to be ambitious and take your welding as far as possible, but experience shows that over-emphasising the importance of pulsing may even be counterproductive if it introduces unhelpful extra difficulty to the already-complex TIG process.
Three key parameters
Pulse welding relies on correct setting of three key parameters. Pulse width is the duration of the pulse across each second of welding (typically 0.1 to 0.9/second). Pulse percentage refers to the relationship between the base current and pulse current. Thirdly, there’s pulse frequency, which is normally anything up to 25Hz. With digital welding machines, set-up of the three parameters is screen-based. Either way, there’s no magic setting for guaranteed results. As ever, experience, knowledge, judgement and practice are the keys.
Though the theory is relatively simple to understand, in practice, knowing how to set up your welder to give just the right pulsing is extremely challenging for novices. Even as a pulsing master, it isn’t a technique where you just dial in three settings to get perfect results every time. If welding is ever an art, pulse welding exemplifies this. There’s no substitute for practice; our best advice is to start in the middle of the available settings range, maybe with a peak-to-base relationship of 1 to 0.5, and experiment.
Do you really need to know pulse welding?
When novice welders ask whether they should pulse or not, our usual advice is to focus on their TIG basics. This isn’t because we’re trying to perpetuate some arcane inner circle within TIG welding. It’s simply because, for most TIG welders, pulse welding shouldn’t be prioritised to the detriment of other TIG skills. Indeed, in some welds, pulsing can even be harmful to good penetration – particularly with very thick materials. There’s also an additional risk of reducing current and heat going into the weld –another threat to weld integrity. Generally too, although a few welders are successful, pulsing is frowned upon for mild-steel work. That’s because it can lead to increased oxidation and brittle welds prone to rusting and cracking.
If you’ve mastered all the TIG basics and are welding to a consistently high level, by all means experiment with pulsing. If not – and please be very honest with yourself – we’d urge you to first focus on the basic TIG welding skills that you’ll use much more.
Call us for advice
With decades’ experience in welding, there’s not much we haven’t seen, including pulsing for TIG welding. Whether you’re just starting, or an experienced TIG welder facing pulsing for the first time, we can help with honest advice – and a great range of welding machines suitable for pulse welding.
Send us an email or call us for a chat!