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Firecracker welding

Dec 26, 2016

Manual metal arc welding is relatively slow, as much time is spent stopping to fit new electrodes and to clean slag before restarting. Firecracker welding allows a weld the entire length of an electrode to be welded in one pass, without pausing. Extra-long electrodes may be used to increase the length that may be welded in one pass, up to 72 inches (1.8 meters).

The need to clean slag from a manual weld before restarting increases the risk of accidental slag inclusion in the finished weld. This risk is avoided through the use of firecracker welding. As the electrode position is also constant relative to the weld, the risk of porosity is also reduced, to the level of a skilled welder. The process is also suitable for use in areas with limited access.Once started it continues automatically, without needing enough space for a skilled welder with sight of the weld.

One drawback is that the size of the bead deposited is limited by the cross-section of the electrode, as there is no scope for manually weaving the arc to deposit more rod in less weld length. For this reason, the flux coating often contains iron powder, to give additional deposition.The rod coating is generally the same as for manual arc, with no change being required. Experiments have been conducted where the coating was thinned on the side in contact with the workpiece, although this does not seem to show a great advantage.