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Pulse MMA: better gap bridging and bead shape

MMA stick welding with a Fronius machine

Pulse is usually talked about for MIG and TIG, but many modern inverters also offer it for MMA (stick) welding. For site work, repairs and root runs where fit-up isn’t perfect, it can make a real difference.

How pulse MMA works

Just like pulse MIG and TIG, the machine switches between a high peak current and a lower background current (see What is pulse welding?). The peak melts the electrode and parent metal; during the background the pool cools and starts to freeze before the next pulse.

The benefits

  • Better gap bridging: because the pool partly freezes between pulses, it is much less likely to drop through a wide or uneven root gap.
  • Easier out of position: the same effect gives you more control on vertical-up and overhead welds.
  • Improved bead shape: a more even, regular bead profile with better wetting at the toes.
  • Less spatter: a calmer pool throws out less spatter, so there is less to clean off afterwards.
  • Less heat input than welding at the peak current all the time, which helps on thinner sections.
Stick welding with a Fronius Ignis

Tips for good stick welds

  • Keep electrodes dry. Low-hydrogen (basic) electrodes in particular need storing and, where specified, baking or holding in a quiver.
  • Use the hot start to get a clean strike, and arc force (dig) to stop the electrode sticking in tight joints.
  • Hold a short, steady arc length and a consistent angle.
  • Match the electrode diameter to the joint and position rather than turning the current up.

Our recommendation for stick welding

For a dedicated, portable stick welder we recommend the Fronius Ignis 180 XT. It has the MMA Pulse function built in, which Fronius says gives better-looking welds and faster welding, especially out of position. It runs on 110 V or 230 V, so it suits site work as well as the workshop, and HotStart and Anti-stick make striking and restriking easy. It is supplied with a 230 V plug, and we can fit a 110 V plug if you ask.

If you also need MIG and TIG, MMA pulse is one of the processes on the Fronius Fortis, alongside MIG/MAG and TIG DC, so one machine covers all three. Browse our MMA (stick) machines and electrodes.

Talk to us

Need a stick welder for site work or a multiprocess machine for the workshop? We’ll help you choose. Call 0141 959 5666 or email info@weldsafe.co.uk.

Images © Fronius International GmbH.