Doesn't Carbon fibre have a transverse coefficient of thermal expansion? i.e. shrinks when hot.
Get some packing tape, stick it to a length of wood. And bounce it off the ground. The wood and outer mast will stop, and the top section inside will keep going.
I wondered how long before a Barntoon was going to show up and yes its another classic 
I would remove the foam here is a picture of a mast that the foam has been removed and the second photo shows the result . Masts works fine . I would sooner lose the foam than start drilling or damage the outer surface .
Sandman, you could be right. So hang it in the tree on a sunny, hot day and when the cold of night arrives it might drop out. 
Barns idea might work. I remember years ago, working in the hardware store, fitting axe handles using the same method. Bang the axe head on the handle about half an inch, then hit the other end until the axe head works its way all the way on.
Select to expand quoteggh said..
I would remove the foam here is a picture of a mast that the foam has been removed and the second photo shows the result . Masts works fine . I would sooner lose the foam than start drilling or damage the outer surface .
^^^ What he said. Some masts come from the factory with no bung in the end of the bottom half. It isn't an issue. And, you could always reinstate with a spare part if you really needed to.
Ok. It's now taped vertically to the clothes line about 3 inches off the ground in a garbage bag full of water, so the water is about 6-8 inches up the mast. Hopefully I hear a bang in the night.
If if that doesn't work in 24 hours I reckon the timber brace with a collar and if that doesn't work its au revoir to the foam
thanks all and keep em coming, especially the ones with the cool drawings!
Hang on I thought you had tried all that and was after a last resort solution....? Barn's one is the most obvious and I thought you had done the "sudden stop" method.....
Then again that didn't stop the missus from getting pregnant.... 
I am also still confused about Grich's solution, I thought you were referring to a collar to grip the inside (skinnier / top) section where it protrudes....)??
Select to expand quoteMark _australia said..
Hang on I thought you had tried all that and was after a last resort solution....? Barn's one is the most obvious and I thought you had done the "sudden stop" method.....
Then again that didn't stop the missus from getting pregnant....
I am also still confused about Grich's solution, I thought you were referring to a collar to grip the inside (skinnier / top) section where it protrudes....)??
Hadnt tried leaving it vertical over time with the end soaking in water Or sudden stop. Had been focused on moving the inside section and not the outside, which is a much better solution
i am reading the collar solution as placing a sleeve over the inside section that butts up against the outside section and pushing / forcing the outside section up, much like the sudden stop method, but in reverse
but clearly I don't know wtf I am doing
Select to expand quoteMark _australia said..
Hang on I thought you had tried all that and was after a last resort solution....? Barn's one is the most obvious and I thought you had done the "sudden stop" method.....
Then again that didn't stop the missus from getting pregnant....
I am also still confused about Grich's solution, I thought you were referring to a collar to grip the inside (skinnier / top) section where it protrudes....)??
the collar fits loosly on the top section but allows you to bump the outer botom sections .you slide it over the small diameter but it wont go past the big section .if there is only 5 mm stiking out and you have a 30 mm collar it will allow the in section to move 25 mm same principle as barns easy if you got a old mast extension collar. you also stand the mast verticaly and tap down and the small section will keep going down.
Select to expand quotegrich62 said..Mark _australia said..
Hang on I thought you had tried all that and was after a last resort solution....? Barn's one is the most obvious and I thought you had done the "sudden stop" method.....
Then again that didn't stop the missus from getting pregnant....
I am also still confused about Grich's solution, I thought you were referring to a collar to grip the inside (skinnier / top) section where it protrudes....)??
the collar fits loosly on the top section but allows you to bump the outer botom sections .you slide it over the small diameter but it wont go past the big section .if there is only 5 mm stiking out and you have a 30 mm collar it will allow the in section to move 25 mm same principle as barns easy if you got a old mast extension collar. you also stand the mast verticaly and tap down and the small section will keep going down.
This and Barns combined are the plan for tomorrow night if gravity + heat + water + time don't work before I get home from work tomorrow
then foam removal
then therapy
cheers
matt
Aaaha Grich now I get it
I would not do that as banging hard object on carbon = bad
IMHO it is a last resort....
Barn's one is niiiiice.
Just make sure that there is something appropriate for the stuck component land on when it comes out. Concrete not good.
I believe Grich62's method may work. However, I would lay the mast on the ground. A firm but not too harsh tap with a piece of wood on the collar as illustrated by Grich62 will separate the two pieces.
The inertia of the inner piece will keep it from moving, while the outer piece is being tapped.
Select to expand quoteMastbender said..
Sorry, couldn't help it, this thread has become hysterical.
Sorry Mastbender, I think you've missed the point of the exercise. Besides the mast remains stuck as AFAIK.
Why don't you find someone with an identical mast, take the bottom piece, dip it in a little sand and double up. All you have to do is solve the same old problem twice.
i think we just solved the question [why is windsurfing not the sport] this poor chap is going to throw away his mast and take up something easy like kite boarding lol. its almost is a comp and the winner is !!!
There seems to be a lot of misunderstanding going on here.
My bet is that if any of us with a little experience turned up we would have that thing out in a jiffy.
If it's just a foam bung in the way just pull it out and tap the mast top with a rod of some sort.
Otherwise tape it to a lump of wood and bump it on the ground as Barn suggests.
These are first order simple efforts. If you can't get it out with either of those then its time to put your thinking hat on.
Select to expand quoteMastbender said..
Sorry, couldn't help it, this thread has become hysterical.
Appreciate and value your input
Select to expand quoteikw777 said..ggh said..
I would remove the foam here is a picture of a mast that the foam has been removed and the second photo shows the result . Masts works fine . I would sooner lose the foam than start drilling or damage the outer surface .
^^^ What he said. Some masts come from the factory with no bung in the end of the bottom half. It isn't an issue. And, you could always reinstate with a spare part if you really needed to.
And the winner is.... The back door foam removal entry.
managed to loosen the foam with a knife then push it down into the mast. It then took some of the impact when I put some timber down the mast to push out the inner sleeve. had to hit it very very hard but it came loose after about 20+ hard hits. No damage done fortunately.
So friggin relieved. Even managed to get most of the foam back in.
thanks all for your advice and thoughts. Greatly appreciated
Ready to get windsurfing now!
Select to expand quotebondy1 said..ikw777 said..ggh said..
I would remove the foam here is a picture of a mast that the foam has been removed and the second photo shows the result . Masts works fine . I would sooner lose the foam than start drilling or damage the outer surface .
^^^ What he said. Some masts come from the factory with no bung in the end of the bottom half. It isn't an issue. And, you could always reinstate with a spare part if you really needed to.
And the winner is.... The back door foam removal entry.
managed to loosen the foam with a knife then push it down into the mast. It then took some of the impact when I put some timber down the mast to push out the inner sleeve. had to hit it very very hard but it came loose after about 20+ hard hits. No damage done fortunately.
So friggin relieved. Even managed to get most of the foam back in.
thanks all for your advice and thoughts. Greatly appreciated
Ready to get windsurfing now!
awesome,was it sand or superglue. glad to here you wont have to take up another sport lol.
Select to expand quotebondy1 said..
And the winner is.... The back door foam removal entry.
managed to loosen the foam with a knife then push it down into the mast. It then took some of the impact when I put some timber down the mast to push out the inner sleeve. had to hit it very very hard but it came loose after about 20+ hard hits. No damage done fortunately.
So friggin relieved. Even managed to get most of the foam back in.
thanks all for your advice and thoughts. Greatly appreciated
Ready to get windsurfing now!
Which was my original suggestion.
The face palm was about how scientific it all became. Glad you're back in business.
Select to expand quoteMastbender said..
bondy1 said..
And the winner is.... The back door foam removal entry.
managed to loosen the foam with a knife then push it down into the mast. It then took some of the impact when I put some timber down the mast to push out the inner sleeve. had to hit it very very hard but it came loose after about 20+ hard hits. No damage done fortunately.
So friggin relieved. Even managed to get most of the foam back in.
thanks all for your advice and thoughts. Greatly appreciated
Ready to get windsurfing now!
Which was my original suggestion.
The face palm was about how scientific it all became. Glad you're back in business.
Thank you. Slight misreading of memes intent
group hug
also, it was sand, and I think maybe even a bit of a vacuum/suction - I could hear water inside the mast, but I couldn't tip it all out. but as you can probably tell - I aint no engineer or physicist
For just stuck masts in general, we've taken to wrap a piece of tape around the joint after joining the halves, the black electrical tape seems to work the best, keeps the sand out.
will definitely be doing both of the above posts and if any other newbies are reading this - treat your mast like a queen and do both of the above!
anyone have a second hand mast bag they don't need anymore? 
