Duck tape vs. duct tape: just don't use it on ducts
As it turns out, "duct" tape was originally manufactured back in the late 1930s and early 40s for the Army to use. It had no name at first, but it soon became known as "duck" tape. The reasons for that are not clear, but one possibility is that since this tape shed water like a duck, so it became known.
"Duck" is also a certain type of cloth, somewhat like what cloth tarps are now made of, and this duck tape was manufactured of that cloth, with the addition of an adhesive to one side of it so that it could be fastened to stuff, and a waterproofing coat to the other. It was used to seal ammunition containers and various other things which suffered from being wet.
It turned out that a hunk of it across the end of a rifle kept stuff like mud, dirt, etc. out of the barrel, a happenstance that could result in inconvenient results to both the gun and the poor GI who pulled the trigger and had the thing explode in his face.
After the war, the color was changed from olive drab to silver, which the manufacturer likely thought would make it more attractive to consumers to use as just a general purpose tape. Shortly after that, because of the silver color of the tape, which matched the color of the new shiny ductwork being installed across the country, "duck" tape became "duct" tape. This was an unfortunate semantic alteration of the name in the minds of the consuming public. The world now thought this stuff was good for sealing ducts.
Far be it from the manufacturer, who was now selling gobs of the stuff to a world just finding the economic power to put modern comfortable heating systems in old houses, to correct this unfortunate renaming. (As leaky as these first systems were, they were "comfortable" only in comparison to what existed earlier in the century, heating systems that depended upon gravity to allow warm air to rise up through huge round pipes sealed by an application of wet asbestos compounds and tapes. The first real ductwork systems were often installed by newcomers to the trade, who found that the silver-colored duct tape was their salvation at making ends of metal meet and not leak.)
So as it turns out, manufacturers, realizing that they had a gold mine on their hands, continued to promote this tape for ductwork systems even after it began to dry out and fall off. As a duct system crack plugger, the stuff was and is worthless.
On a service call I once went on, the forced-air oil furnace's chimney pipe was, the customer said, smoking. The furnace itself was located on the main floor because of a wet basement. The floor was wood covered by old linoleum, a product that is made of some filler materials and a petroleum product, as anyone knows who has thrown some into a fire. It burns like gasoline.
The first thing I noticed upon examining the furnace was that the chimney flue pipe, which had a joint each two feet, and a joint wherever there was an elbow, had been extensively sealed up with silver "duct" tape. The interior of the pipe was full of soot, which was in fact why it was leaking smoke, which the customer thought the duct tape would stop.
To make matters more interesting, the flue pipe extended through a frame and plaster wall into a chimney some four or five feet on the other side of that wall. There were a lot of joints in the pipe, each with four or five wraps of duct tape.
An examination of the inside of the furnace showed large accumulations of soot, so much that I hesitated at trying to clean it out. I was on the main floor of the house, and no matter how hard one tries, soot seems to find its way on to everything.
A company had just come out with a combustion chamber cleaner called a "soot stick." One could just throw this tube of chemicals into the heat exchanger, according to the directions, and there it would combine with the burner flame to burn that soot up and send it up the chimney. Great. I started the furnace and pitched in a stick.
Within a very few seconds, I realized that the soot stick was producing dangerously high temperatures inside the heat exchanger. Within a very few seconds more, with alarm, I saw the flue pipe, right where it left the furnace, become so hot that it turned cherry red. The cherry red began to move along the flue pipe as the chimney pipe continued to overheat, and when it got to the first duct-taped joint, that duct tape burst into flame, and pieces began to fall down to the "gasoline" floor. I stomped out that fire and turned to run for the service truck to fetch a fire exchanger, only to realize that the cherry red had reached the next joint and its duct tape had burst into flames and was dropping large flaming gobs onto the linoleum.
At this point, the furnace had reached such a rate of combustion that it began to rumble and shriek and emit popping bursts of flame and smoke out its four-inch inspection hole.
Things weren't looking very good. I was dancing around like a mad man, stomping out dropping pieces of flaming duct tape, unable to run out to the truck for the fire extinguisher. The cherry red was almost to the wall, where it would most certainly have set the house on fire, when suddenly everything quieted down, and my heart rate went back to normal.
Duck tape is great for wrapping packages. It even saved one of the moon vehicles when an explosion damaged their carbon dioxide scrubber. It makes a great emergency bandage for a finger cut and will hold tennis shoes together another month.
It is not, regardless of its name, "duct" tape.