What is the normal tap time range for a standard thermite weld?

The normal tap time range for a standard thermite weld is typically 15 to 35 seconds. This duration refers to the time needed for the molten metal produced by the thermite reaction to fill the joint and solidify properly.

In thermite welding, once the reaction has taken place and the molten metal is ready, the tap time is crucial in ensuring that the weld penetrates appropriately and establishes a strong bond between the workpieces. A tap time that is too short may not allow adequate molten metal to flow into the joint, leading to a weak weld. Conversely, a tap time that is too long can result in excessive loss of heat and potential oxidation, compromising the quality of the weld.

The range of 15 to 35 seconds is based on practical experience and ensures that the weld achieves the desired mechanical properties while minimizing the risk of defects. The other ranges provided in the question either start or end outside of this optimal window, which can lead to less effective welding outcomes.