MMA Welding AluminiumMMA may be used to weld aluminium but the process is difficult to use, does not give good quality welds and leaves an aggressive slag that must be thoroughly cleaned off after welding, so it has been largely superceded by MIG and TIG. Standard DC MMA equipment, such as a transformer-rectifier or motor-generator, can be used. MMA electrodes are aluminium, or aluminium alloy, and have very active, corrosive flux coatings containing fluorides and chlorides. They are generally to an Al-Si formulation and operate on DC+ welding current. Welds from this process are very prone to gross porosity and the main causes of porosity are moisture in the electrode coating, incorrect welding technique, and poor cleaning of components. Cracking in susceptible alloys is also a problem. MMA welding aluminium can produce irritant particulate fume due to the components in the fluxes.
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