When you first heard of duct tape as a kid, you likely thought the term was duck tape — and you were likely right:
The origin of the name of the product, “duck tape” or “duct tape”, is the subject of some disagreement.
One view is that it was called “duck tape” by WWII soldiers either because it resembled strips of cotton duck (canvas) or because the waterproof quality of the tape contributed to the name, by analogy to the water-shedding quality of a duck’s plumage. Under this view, soldiers returning home from the war found uses for duck tape around the house where ductwork needed sealing. Other proponents of this view point to older references to non-adhesive cotton duck tape used in Venetian blinds, suggesting that the name was carried over to the adhesive product.
The Oxford English Dictionary says that perhaps “duct tape” was originally “duck tape”. This view is summarized most notably in a New York Times article by etymologist William Safire in March 2003. Safire cites use of the term “cotton duck tape” in a 1945 advertisement for surplus government property. The Brooklyn Daily Eagle uses the term “duck” in 1902 quotation for “100,000 yards of cotton duck tape” being used to protect the cables of the Brooklyn Bridge. Thus a fabric duck tape was available to which an adhesive could have been added.
It gets better. Duct tape is not good for duct work:
Late in 1998, scientists at the Lawrence Berkeley National Laboratory made a startling discovery — ever-popular duct tape was useful for hundreds and hundreds of tasks, but holding ducts together wasn’t one of them.
Over three months, researchers tested duct tape and 31 other sealants under accelerated laboratory conditions that mimicked long-term use in the home. They heated air to nearly 170 degrees and chilled it to below 55 degrees before blasting it through ducts. They baked ductwork at temperatures up to 187 degrees to simulate the oven-like conditions of a closed attic under a hot summer sun.
Of all the things they tested, only duct tape failed — and they reported it failed reliably and often quite catastrophically.
Instead of using duct tape, the researchers recommended sealing ducts with mastics, gooey sealants that are painted on and allowed to harden. Metal ducts should be held together with sheet metal screws; flexible duct connections should be secured with metal or plastic bands.