You raise a valid point. The term "duct tape" is indeed derived from its primary use in sealing and securing ductwork in HVAC systems. However, the origin of the name "duck tape" is a subject of some debate and uncertainty. Here are a few theories that attempt to explain the alternate name:
Mispronunciation and Misinterpretation: It's possible that the term "duct tape" was mispronounced or misinterpreted as "duck tape" over time. The phrase "duct tape" can be challenging to enunciate clearly, and the similarity in pronunciation between "duct" and "duck" may have contributed to the alternative name.
Waterproofing and "Duck" Brand: Some theories suggest that the term "duck tape" originated from the waterproofing properties of the tape. The fabric-based tape was believed to repel water, similar to how water rolls off a duck's feathers. Additionally, the brand "Duck Tape" produced by Manco, Inc. (now ShurTech Brands, LLC) in the mid-20th century could have contributed to the popularization of the term "duck tape."
Military Connection: During World War II, the U.S. military used a waterproof cloth-based tape for various applications, including repairing equipment and sealing ammunition boxes. This tape was known as "duck tape" due to its waterproofing characteristics. It is speculated that the term may have transitioned to the more general-purpose "duct tape" as the tape's usage expanded to include HVAC applications.
It's important to note that "duck tape" is often used colloquially and informally, while "duct tape" is more commonly used in technical and professional contexts, especially within the HVAC industry.
Overall, the precise origin and evolution of the term "duck tape" are not definitively known, and it may be the result of a combination of factors, including misinterpretation, pronunciation, and historical usage.