2 piece driveshafts

ever wonder what these things looked like opened up? Just for grins, trying to determine how I could shorten this (I think it is hopeless) I cut one. first cut was over the rubber so it didnt seperate so I thumped it until I heard a hollow part and put my pipe cutter to work. I caught about 1/8 of the rubber but it came off cleany and with a little pop like a biscuit tube from the refrigerator section! The rubber insert expanded as I pulled it off, interesting..so I cut a slit on the remainder of the rubber bonded tube and walked around the bench to get something. I heard something drop and went back and found the tube had split where I scored it, and it split pretty good. Seems that rubber in there is under considerable pressure. I pried the other half off and found rings of vulcanized rubber supporting the inner shaft to the outer shaft. I guess that stuff is pretty strong as it can take more than 300 ft/lbs of torque right? Here are a few pics to file in the "stuff you dont really need to know" folder. The weld yokes are welded to flared ends of the tubes so you cant really shorten these in a standard fashion. Now how they manufacture these, good question. Does the liqued rubber expand after being injected into there and vulcanize?