Regarding tack welding, who is correct? Technician A does not use filler rod, while Technician B asserts that tack welds align parts.

In the context of tack welding, both statements made by the technicians are accurate, which supports the understanding that the correct choice is that both technicians are correct.

Tack welding serves a specific purpose in metal joining, particularly in the context of assembling parts before performing a full weld. Technician A's assertion that no filler rod is used aligns with the common practice in tack welding, where the objective is primarily to hold parts in position, rather than to create a finished weld.

Meanwhile, Technician B's claim that tack welds are intended to align parts is also true. The primary function of a tack weld is to temporarily secure portions of the workpiece in the correct position, ensuring proper alignment before the final welding steps are undertaken. This process greatly enhances the accuracy and quality of the final weld.

By supporting their respective claims with the roles that tack welds play in assembly and the techniques employed, both technicians contribute to a comprehensive understanding of the fundamental concepts in collision repair and refinish work.