I am in the HVAC industry
I am hear to tell you that it is spelled duct tape and to also put to rest the pronunciation ..... and I can spell ...........
The industry standard is the T is silent
but not ck
it is pronounced by us proffesionals as
DUK TAPE ..............................
you heard it here first ........................................
It has been sugested to use this product properly it takes a 6 week S.H.I.T. course
It also doubles on Sundays as (200 MPH tape)
SHIT = Super High Intensity Training