About duck tape, from wikipedia -
In fact, if you read through the article it seems the term "duck tape" predates "duct tape". This is because originally the backing was made of "cotton duck" cloth. Duck Tape is now a brand name though. It's not really the best choice for duct work due to the way it deteriorates after a few years.
 
				
		 
 
		 
 
		


 
 
		 
 
		 
			 
 
		 
 
		
 
 
		 
 
		 
 
		 
 
		 
 
		 
 
		 
 
		 
 
		 
 
		