Welding is a popular method of permanently joining various materials, most often steel, but also plastics. However, this requires careful care and proper preparation. Arc welding (MMA) is one of the most popular welding methods. The electric arc created in this process reaches temperatures in the order of 4000 °C, and appropriate current parameters are required for its creation. So how to MMA welding and what equipment to use? See our welder's guide and learn all about MMA welding.
MMA coated electrode welding – description
For MMA welding, a special electrode is used, consisting of a metal core and compressed coating. That is why it is called a coated electrode. The weld joining the elements is created by melting the electrode and creating the so-called weld pool – a liquid metal that solidifies creates a permanent connection. To obtain a sufficiently high melting point, an electric arc is used, which temperature reaches up to 4000 °C.
The undoubted advantages of MMA welding include the possibility of joining various types of metals and alloys. Welding can be carried out in any position – including underwater. MMA welds have good mechanical properties. Unfortunately, this method also has its bad sides. First of all, it is not particularly efficient, welding itself is quite slow (up to 40 cm/min) and due to its function, the electrodes are shortened and require regular replacement. MMA welding also generates large amounts of welding gases and fumes.
How to weld using MMA method? Welder's guide
At the beginning it is worth explaining which devices and accessories will be useful and necessary in the MMA welding process. You will definitely need a transformer welder with an electrode holder and a ground wire terminated with pliers. In the case of field work, where there is no access to a source of electricity, welding power generators (commonly called motor welders) are used. The second and also necessary element is the electrode. After the welding process is completed, angle grinders and metal brushes are often used to clean and even the weld surface.
How to weld step by step:
Step 1 – connect the welder to a power source (or start the power generator) and tighten the pliers with the ground wire on the work piece.
Step 2 – rub the electrode tip against the welding location and move it away to trigger an arc.
Step 3 –Maintain a constant distance between the electrode and the workpiece, usually around 2 – 3 mm. This distance should be equal to the diameter of the electrode used.
Step 4 – Welding should be carried out holding the electrode at an angle of approximately 60° to the weld plane. It should also be noted that the length of the electrode will shorten over time and the distance between it and the surface to be treated should be monitored on an ongoing basis.
Step 5 – welding ends when the electrode is moved away from the material (first, move the electrode back slightly along the joint, then move it firmly away). After the weld has cooled down, you can clean it with a wire brush and level it with e.g. an angle grinder.
Recommended welding power generators
In places where access to a constant source of electricity is difficult or impossible, welding power generators are used. It should be noted, however, that they must be devices providing adequate parameters of electric current. We have reliable power generators from proven brands such as Pramac, Sumera Motor, Endress and Benza.
This is the basic version of the three-phase aggregate with manual start and a 429 cm³ motor with 14 HP. The equipment has a welding current in the range of 40 – 220 A DC and generates a maximum power of 7.3 kW. Standard equipment includes 1 400 V / 16 A socket, 1 230 V / 6 A socket and welding quick connectors. The aggregate itself also has a thermal protection and oil level sensor.
This equipment has a continuous power of 4.16 kW and welding current from 40 to 220 A / 170 A (at 60% load). The aggregate is equipped with a 7.7 kW gasoline engine and can work for approx. 2.8 hours on a full fuel tank (at 75% load). Allows handling electrodes with a maximum diameter of 5 mm (for rutile, alkaline and cellulose electrodes).
The aggregate is equipped with a socket SCHUKO 230V 16A IP54, 2P + T CEE 230V 16A IP44 and 3P + T CEE 400V 16A.
This aggregate, despite its considerable weight (145 kg) can still be successfully used as a portable source of electricity. It is powered by a 21 HP gasoline engine and 3.5 l / h fuel consumption (at 75% load). Generates welding current in the range of 30 – 300 A and allows the handling of electrodes with a diameter of 6 mm (rutile, cellulose) and 5 mm (basic).