I usually tape around the mast junction and I never had any problems in disassembling the mast so far, even though there is a lot of fine sand and silt around the beach and in suspension in the water.
For some reasons, though, the last three sessions on the very same lake I usually sail, the mast now gets blocked.
I suspect the water may seep in from somewhere else. I have to know it, otherwise I 'll always have the problem, even if I lubricate the junction with soap or grease before assembling the mast..
I seem to remember that a sort rubber plug once came out from inside the mast , but I didn't put it back in and I misplaced it. It is not the plug at the top of the mast, though. That one is still there.
Maybe this inner plug is what prevented water from getting into the junction from the mastbase extension .
Any suggestions?
Thanks
Francone
Google "how to separate a mast" and you'll get a heap of results including threads from Seabreeze.
Good luck
You can attach a boom on the lower mast end and another on the upper mast end,get one person to turn clockwise or anti clockwise (whichever) while you hold the other boom steady or turning the opposite way.Hope this helps 
Put your extension in the mast then use a rubber mallet and give it some steady knocks along the vertical fo the mast. It will slowly move it apart.
Select to expand quoteFrancone said..
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I seem to remember that a sort rubber plug once came out from inside the mast , but I didn't put it back in and I misplaced it. It is not the plug at the top of the mast, though. That one is still there.
Maybe this inner plug is what prevented water from getting into the junction from the mastbase extension .
Any suggestions?
Thanks
Francone
I thought you were on the money there, but I just realised, it would be very hard for grit to get in the join from the lower section. Have you given the top half a good hose out? If there's grit up there it will make it's way into the join every time you rig.
But thinking a bit more, if the joiner isn't sealed into the bottom section water may be getting past. Easy to check, just put water into the base and see if any comes out at the joiner. If it does, it needs to be fixed, a lose inner tube could lead to mast damage.
Some masts have no plugs at all and it does not seem to affect the outcome
Don't hit it, that's a last resort. 4 blokes twisting and some bouncing.
Turn mast upsidown fill with water and wiggle wiggle wiggle. Eventully gets the grit out.Thats if you have no friend's and only one boom.
being really good at sticking masts together i agree with both methods mentioned above , two booms works really well , i usually try to have them as close together as possible. Have also separated some dooseys by pouring cooking oil around the joining area and leave for a while and then wack the base with a rubber mallet , after a few wacks you will see the top half slowly separating . good luck
Always fun to have a mast separation get together at the end of a session (As described by Mark)
I think our record was 3 masts needing separation 
I still really disagree with hitting it with anything or using any mechanical method other than booms. Carbon is brittle, little whacks can cause microscopic cracks that you won't know about til it goes bang one day.
I am also not sold on the icicle hitch and tow it with a car method, as I reckon it must pull a little bit off axis.
Only ever heard of one that would not separate, and the manufacturer replaced it. Apart from that one widely reported here, has anybody ever not separated a mast with lots of people, bouncing it and maybe flushing also?
So far this has never let me down stand it vertical in the grass and shake the living sh#t out of it and it will loosen it rotate your grip and so on it should come loose and only one person is needed the low frequency has a lot of energy good luck!
Another simple one that has never failed to release a stuck RDM for me.
Get a person on each end of the mast holding it horizontally. Place the mast join area on a coppers log horizontal fence post or wooden bench top rail with a towel on it, anything that won't damage the mast.
Both apply downward pressure to flex the mast about 30cm then roll the mast while flexed. The action of rolling while flexed work's the joint and within seconds the mast is free with no struggling.
Yep Mark, i returned a borrowed mast at Christmas time this year. No one at corros could get it unstuck. 30 odd people tried. Every possible way tried. The more we moved it the harder it got until it seized completely.
chuck it in a swimming pool overnight then get eight men to twist opposite ways....or eight topless chicks if you have already tried the eight men and failed! 
