Duck Tape is now a brand name of adhesive, plastic-coated, fabric tape, but it was originally the generic name of strips of duck material. The original was not adhesive, but was useful in applications from shoemaking to preventing the corrosion of steel. Neither the original nor the current is suitable for using on heating ductwork.
Duct tape is now the more common, generic name of adhesive, plastic-coated, fabric tape. It also is not suitable for use on heating ductwork.
If you need tape to seal your heating ducts, be sure that it specifies that it is made for that purpose. It will be more like foil than cloth tape.
If you are interested in making clothing from duct tape, as mentioned in last week’s Muddle, and you are a senior in high school in the United States or Canada (with some regional restrictions), check out the Duck brand contest. Each year they provide scholarships to the creators of the best prom dress and best tux. If you are interested in knowing more about it or seeing winners from previous years, you can do that here: https://www.duckbrand.com/stuck-at-prom
Last week we saw that a space can make the difference between a noun and a verb. This week a single letter makes the difference. The more-frequent use of marinade as a verb in the last decade has led some dictionaries to accept it as an alternative, but it is still unacceptable to many. My recommendation, for the sake of clarity and to avoid harsh judgement from language purists, is to use marinate as the verb. Marinate has been in use as a verb since the 1640s.
If you can logically place a word between “set” and “up”, you need a space. For example, you can say that you need to set up the computer, and wonder whether there should be a space or not. But you can also say that you need to set the computer up. Now it’s obvious that you need the space. Either way, once you finish the job, you’ll have a great computer setup.