The best way I have found to get two round things apart eg. two piece windsurfing mast is to use those new soft wrenches that wrap around and cinch down on what you are tring to loosen. Put one on each end close to the joint and twist in oposite directions. Guaranteed to come apart. Good luck. Copy the link below to see the tool I mean at sears.com.
http://www.sears.com/sr/framework/ho...vertical=SEARS