MMA (Manual Metal Arc) welding — also called stick welding or Shielded Metal Arc Welding (SMAW) — uses a flux-coated consumable electrode to strike an electric arc between the electrode and the workpiece. As the electrode melts, it forms both the weld metal and a protective slag layer, making the process portable, reliable and well suited to construction, structural steel, maintenance, shipbuilding and outdoor fabrication.
This hub is your starting point for everything MMA. Below you will find how the process works, the main electrode classifications, how to choose and store electrodes correctly, and how MMA compares to MIG and TIG. Each section links to a dedicated in-depth guide.
What is MMA welding and how does it work?
MMA welding creates an electric arc between a coated electrode and the parent metal. The heat melts both the electrode and the workpiece, while the electrode coating burns to form a protective gas shield and a slag layer over the cooling weld. That slag must be chipped off before inspection or before laying down further weld passes.
Because the shielding comes from the electrode coating rather than a separate gas supply, MMA performs well outdoors and in windy conditions, and it copes with rusty or painted steel better than some other processes. That portability and versatility is why it remains a mainstay of site work, heavy fabrication and repair.
Read more in our guide to how MMA welding works and its advantages. When it comes to the machine itself, our guide to choosing and buying an MMA welder explains the features that matter — hot start, arc force, OCV and duty cycle.
Understanding MMA electrode classifications
Most of the skill in MMA welding lies in choosing the right electrode. Electrodes are grouped by their coating type and their mechanical properties, and the common numeric classifications tell you what each is for:
- 6013 — a popular, easy-to-use general-purpose electrode for mild steel fabrication and repair.
- 7018 — a low-hydrogen electrode for high-strength structural, pressure-vessel and coded welding.
- 6010 — a deep-penetration electrode used for pipe root passes and heavy structural work.
- 7016 — a low-hydrogen electrode similar to 7018, valued for impact toughness.
Our guide to MMA electrode classifications (6013, 7018, 6010, 7016) explains each one and the key differences between them.
Rutile vs basic, and the importance of low hydrogen
Electrode coatings broadly split into rutile (titanium-dioxide based, easy to strike, attractive welds — 6013 is a common example) and basic (low-hydrogen coatings that minimise cracking and produce high-strength welds, but demand more skill and careful storage).
Low-hydrogen electrodes matter because hydrogen trapped in a weld can cause delayed cracking. They are essential on thick steel sections, high-strength steels and structural work where weld integrity is critical. Learn more in rutile vs basic and low-hydrogen electrodes explained.
Storing and drying MMA electrodes
Many electrodes — particularly low-hydrogen types — absorb moisture from the air, and damp electrodes cause porosity, excessive spatter and hydrogen cracking. Electrodes should be kept in dry conditions, with electrode ovens used where recommended, and resealed or returned to the oven when not in use.
Our MMA electrode storage and drying guide covers dry storage, electrode ovens, why electrodes become damp, and when damp electrodes can safely be re-dried.
Choosing the right electrode for the job
The right electrode depends on the material, the application and the welding position:
- Mild steel fabrication — 6013 for general work; 7018 for structural or coded welds.
- Structural steel — 7018 low-hydrogen for high-strength, tough welds.
- Outdoor welding — MMA generally beats MIG; 6013 for general work, 7018 for structural.
- Vertical welding — 7018 is commonly used for vertical-up welds.
- Pipe welding — 6010 root passes with 7018 fill and cap passes.
Electrode size also matters: 2.5 mm for thinner material, 3.2 mm and 4.0 mm for heavier fabrication. See choosing MMA electrodes by application.
MMA vs MIG vs TIG
MMA is portable and outdoor-friendly; MIG welding is generally faster and better for workshop production; and TIG welding gives the greatest precision and cleanest welds on stainless and thin material. Our guide to MMA vs MIG vs TIG welding helps you pick the right process for the material, environment and weld quality you need. For a broader walkthrough of process and machine selection, see how to choose a welding machine.
Buying MMA electrodes
When you are ready to buy, our guide to buying MMA electrodes brings selection, size and storage together so you order the right consumables first time. For the wider consumables range, see our welding consumables hub.