I saw the Akira scene with Cracker and a lightbulb when off in my head Mingo can create strings. He is not made of strings. So it would make sense that his awakened power could transform objects into strings. Luffy cannot create rubber. But he is made of rubber. It would make sense if his awakened form let him control the properties of the rubber indefinitely. Anyone gets a feeling that Luffy's Gears are a type of a forced awakening? Hence why he cant use his power indefinitely like Mingo can. I imagine that when luffy awakens his DF, he wouldn't have a need for gears.