RE: Stuck mast
Glad to be of service here.
Not sure if you've seen the "water pressure" mast separator I put together.
Might want to get a hose coupling, an ABS plastic adapter, a 1 foot piece of hose, and a couple of hose clamps.
With this device you can use city water pressure to "wash" the sand out of your stuck mast joint. You can also "work" the joint in the same way that just worked for you, with the water pressure inside the top of the mast at the same time. Very quick results.
Did your mast "stick" even with tape around the joint?
Hope this helps,