What year was duct tape invented?

http://en.wikipedia.org/wiki/Duct_tape
my guess is 1942

Sweet guys thanks

[mod says]: Removed uncited copy-paste.

1942. its original invention was to seal ammunication cases, to make the waterproof, during the war.

Adhesive tape (specifically masking tape) was invented in the 1920’s by Richard Drew of Minnesota Mining and Manufacturing, Co. (3M). Duct tape (the WWII military version) was first created and manufactured in 1942 (approximate date) by the Johnson and Johnson Permacel Division. Its closest predecessor was medical tape.
The original use was to keep moisture out of the ammunition cases. Because it was waterproof, people referred to the tape as “Duck Tape.” Also, the tape was made using cotton duck – similar to what was used in their cloth medical tapes. Military personnel quickly discovered that the tape was very versatile and used it to fix their guns, jeeps, aircraft, etc. After the war, the tape was used in the booming housing industry to connect heating and air conditioning duct work together.
Soon, the color was changed from Army green to silver to match the ductwork and people started to refer to duck tape as “Duct Tape.” Things changed during the 1970s, when the partners at Manco, Inc. placed rolls of duct tape in shrink wrap, making it easier for retailers to stack the sticky rolls. Different grades and colors of duct tape weren´t far behind. Soon, duct tape became the most versatile tool in the household.

Quoted from:

http://www.ideafinder.com/history/inventions/ducttape.htm

Around the time of World War II….BUT….I bet Red Green knows for sure!