Is it legal to go buy longer pieces of string for a winch&pulley system? I know the rules say that we can use anything the is equivalent to something we can get from the VEX website. Could we buy identical string on a longer strand and still be legal under this rule?
No, this would not be legal. Using pieces of string longer than are available in the VEX Robotics Design System would violate <R7b>, quoted below.
What if we used two pieces of rope that were the same length as sold in the winch&pulley kit and spliced/melted/tied them together?
Splicing and tying the legal pieces of rope together is allowed; however, melting is not legal. Please see <R15b>, quoted below, for more information:
Online, it specifies the rope from the winch&pulley kit as just nylon, braided. I went and purchased some braided nylon rope that is the same diameter as the rope from the kit, but the braiding is slightly firmer. Will we be allowed to use it? And if not, how stringent are the regulations, when online there are no details that give us the exact specifications for the VEX rope?
The final determination of whether a part is considered to be “identical” to a VEX part will be made by the inspectors at your event. From what you’ve described, it sounds like the rope would be legal, however it’s difficult to determine without being able to see/touch/feel the rope you’re using.