Windsurfers have been battling with this problem for years. How to separate to pieces of carbon fibre/fibreglass that have seized up after a bit of neglect.
And the same problem happens with split paddles. Salt or sand can get between the male and female connectors when putting them together and make separation after use almost impossible. And the problem is even worse with alloy paddles. Saltwater can react with metal and actually fuse the pieces together.
So firstly, prevention is better than cure. So make sure you keep your connectors clear of sand and salt water as far as possible. Not always possible in a shoreline gale, but try. And make sure you separate your paddle as soon as possible after finishing, clean it with freshwater, and always keep it in its protective bag.
And mud, grit, sand, saltwater can all get into the connector if you have a loose connection, so keep your connector as tight as possible (without overtensioning!)
But, sometimes, after a paddle, we don’t always have the energy to properly washdown the kit. You just chuck the paddle in the back of the van in one piece, with good intentions to wash it down and separate it when you get home. But when you get home it’s late, you need dinner and a beer, so you leave it until Monday. And Monday turns to Tuesday, and before you know it a week has gone past and the paddle is now stuck firm. So, what do you do?
So assuming you’ve enlisted the help of friends and tried brute force, twisting and yanking, the next thing to try is lubrication.
Letting washing up liquid seep into the connection overnight is often enough to allow enough movement for twisting and yanking on day two. If it’s not looser on day two, then leaving it soaking with washing liquid any longer won’t work.
So the next thing to try is hot and cold. Put the kettle on, and also fill a bowl with ice and water. Once the kettle has boiled, poor the icy cold water over the part of the shaft that has the male connector, and then the boiling water over the female connector. If you’re able then poor the icy water inside the paddle (this is sometimes possible with 3 piece paddles). And then resort to twisting, yanking and pulling again. Using strap handles to get a better grip on the stick often yields dividends. And make sure to keep enough in the kettle to make yourself a cuppa in celebration or commiseration!
If this doesn’t work, things are getting desperate. You’re now getting into the territory of methods that might damage your stick.
You can repeat the above replacing the icy water with freeze spray (available from most good hardware shops)
Trying to bend the paddle enough to slide a butter knife between the two section can work. Using the knife as a lever to prise the two sections far enough apart enough to allow lubricant or freeze spray to penetrate more thoroughly can also work, but you risk damaging the carbon fibre at the end of the sections.
The very last thing to try is using a vice to hold the upper section firm (use a teatowel to protect the shaft as best you can, but there is a real risk of damaging the stick now!), and twist the blade with all your strength.
If all of this hasn’t worked, the you’ve got a veritable sword in the stone. Then all you can do is take a saw to the shaft. Sawing through the male section will hopefully allow you to work the stuck male section out from the inside, and then at least leave you with an undamaged female section. Obviously this is your very last resort. Unless you know King Arthur.