I have managed to get an ungodly amount of sand and what seems to be cement lodged between the two halves of my mast and of course it is stuck now as a one piece.
I have tried brute force with several people either side of the mast pulling and twisting. As well as using two booms clamped as levers. Are there any ingenious solutions to this?
Thanks in advance.
fill your esky with beer and ice then use some ice to fill mask up past the join, after a while pour hot water on the out side of the join (be careful not to course it to crack)
If that fails drink beer 
note: I have never tried this, but you did ask for any "ingenious solutions"
Flex the mast, ie support both ends and bounce it up and down, rotate bounce again.
the 2 halves should separate as you repeat the bouncing rotating.
Then try the 2 booms
Brute force and a couple of strap wrenches works for me:
www.bunnings.com.au/haron-160mm-strap-wrench_p4900119
I had used the following method to help a couple of people to sort out a severely stuck mast. Here is how...
(1). You need a strong and firm anchor point. Your car's tow-ball will be ideal.
(2). A strong piece of rope. Rope about the thickness of your harness line would be ideal.
(3). You need to create a means to securely attach your mast. The attached diagram shows what an "abseiling rope knot" is.
(4). You need to tie up the loose ends of the rope as shown so that you have a closed loop.
(5). You need to have a long enough rope so that you have at least 30 cm of free-play. This is to build up the momentum when you give it a mighty tug.
Here are the details explanations...
The "abseiling rope knot" provide a dead grip on the mast. The tighter the rope is, the firmer the grip will be. The rope should be over the bottom section of the mast because it is fatter. Now you place the knotted end over the tow-ball,
with the bottom end facing away from you, and you are pulling on the tip end of it. As I said earlier, you should have at least 30 cm of free-play.
Now get at least two people to hang on to the mast. You then move the mast forward as far as the 30 cm of loose-play allows. You both synchronized 1-2-PULL. In fact, it is more like a strong jerking motion. You will, if you are lucky, see the base begins to move a bit. The rope will not give by virtue of its design. You can pour some water or may be WD-40 at the joint.
Of course, you need to make sure that the rope is a good, strong one.
Next time its really windy use that mast for a few hours then try to release it.it might sound strange but it should work.goog luck.
Support both ends. I would let it warm up in the sun for 10 min or so. Gently sit on the mast on near the mid section and when the joint opens up insert a 5 cent piece. Turn mast 180 degrees repeat. Turn the mast 180 degrees insert 10 cent piece. I have separated a few masts like this after having read this on sea breeze a couple of years ago.
Select to expand quotewhippingboy said..
Flex the mast, ie support both ends and bounce it up and down, rotate bounce again.
the 2 halves should separate as you repeat the bouncing rotating.
Then try the 2 booms
This ^^^
In a bit more detail.
Get someone to pin the top of the mast to the ground.
Hold the bottom of the mast and start to whip it up and down violently and fast, to get the maximum bend in the mast. Do this for a minute. What that does is grind the sand particles in the joint as the two parts of the mast flex at the joint.
Turn the mast 90 degrees and repeat.
You need about 3 strong volunteers to hold each half of the mast and twist in opposite directions while pulling it apart. Or you can try clamping booms tightly to both halves of the mast near the joint and try to twist the joint in opposite directions.
If it doesn't come apart, repeat the process again.
Submerge it, and work it under water. Shouldn't need much force and it will come undone.
If it's reasonably tough you can pull it apart with a car.
Tie it with straps to distribute load and use an "icicle hitch".
I use the hold the mast vertical the right way up then hang onto the mast at chest height and shake the sh#t out of it and the frequency will make it come apart ive done this a few times with various mast mates and mine and it works every time 
Select to expand quotestroppo said..
I use the hold the mast vertical the right way up then hang onto the mast at chest height and shake the sh#t out of it and the frequency will make it come apart ive done this a few times with various mast mates and mine and it works every time
Sounds like a single person version of the bounce method - handy to know!!
I've always found the bounce method to work when the brute force methods (two booms, lots of guys) have failed.
I would use wobble and bounce in all it's variations (incl the coin method) LONG before I consider anything mechanical.
lots of the knots used get too tight and can crush it. Banging it can fracture carbon on a microscopic level and cause failure later on the water
Select to expand quoteNotWal said..
If it's reasonably tough you can pull it apart with a car.
Tie it with straps to distribute load and use an "icicle hitch".
It's amazing how strong just a few bits of fine sand can in a mast join can be! Have had to actually put the foot down on some occasions!
The car thing works when all else fails, every time and you can sort it out yourself with no help.
Select to expand quoteMark _australia said..
I would use wobble and bounce in all it's variations (incl the coin method) ....
Never heard of the coin method. Details?
I tie roof rack straps round each end of the mast just using lots of half hitches, to distribute the load over a large area.
They all tighten a bit instead of just one bit of rope on one small area. Then tie one end to your tow bar and the other to a tree/post, and drive away very slowly. I use the whole strap for the half hitchs so the mast is then close the towbar/post to stop it flying back It has always worked for me and doesn't take long or any effort.
Select to expand quoteHarrow said..Mark _australia said..
I would use wobble and bounce in all it's variations (incl the coin method) ....
Never heard of the coin method. Details?
See Dean 424s posting above
The bounce wobble method works. I used this method successfully last month.
The problem with the car pulling method is that you build up tension in the pulling rope and when the joint comes free this tension then propels the piece of mast towards the car, often with catastrophic results. A fantastic video, which shows this in graphic detail, was posted on a Seabreeze forum on the same topic not to long ago.
Just remembered another method I witnessed.
Lay mast flat on picnic table, go to top of mast. Hold top half tight, strike top end of mast with rubber mallet (Hard),
Bottom half of mast goes flying off 
Wouldn't do it myself but it was funny when I saw it done by ....
Select to expand quoteThe problem with the car pulling method is that you build up tension in the pulling rope and when the joint comes free this tension then propels the piece of mast towards the car, often with catastrophic results.
To get round that, just tie the mast with no spare rope/strap to the tow bar. I have the mast literally touching the underside of the bar so it can't go forward. Same with the other end of the mast on the post.
Thought an update is necessary. I left the mast in the sun for a couple of hours this morning and tried the coin trick. The joint is too small for a five cent coin so I uses a small flathead screwdriver I have but was worried about cracking the carbon too much.
I gave the shaking method a go. It's a 370 mast so there wasn't much leverage (might consider putting a weight at the top) but I still saw a noticeable amount of dust/sand come out so good signs so far.
The issue I had with using the two boom method was not enough friction to alleviate the leverage. The boom clamps themselves seem too large.
I would keep trying but work calls. Thanks all for the suggestions, I'll keep at it tomorrow.
