Cad welding has a common use in the joining of reinforcing steel bars. A sleeve similar to a heavy wall pipe serves as a crucible and is placed over the connection which has a gap between the ends. Thermite powder is poured through a hole which also serves as the ignition point. A oxyacetylene torch is used to ignite the thermite which by the way burns at a furious rate melting the bars together. The result is a full section splice which has strength equal to or greater than the reinforcing steel. I believe that rail tracks are done similarly except that there is a mold serving as a crucible to contain the thermite which does not become part of the finished weld. Cables such as buried grounding grids are done on a much smaller scale to form a permanent joint as mechanical compression connectors can fail over time. Although I have seen cadwelds done to 2 - 1/4 " rebar when I worked in the nuclear construction field, Ive never performed the process. Maybe some other folks can shed some light on this matter.
Steve Dodd
Dodd Welding Services
Newtonsville, OH
DODDWELDS@aol.com
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