Seperating an Angel RS600 Mast

My main reason i want to seperate it, is so i can replace the old corroded bottom section with my far better condition spare, i dont want the mast to go bang on a windy day.

I have kinda given up all hope of seperating it, so i may just use it as is.

I want to see how it feels compared to the superspars mast.

Dan

Originally posted by hollandsd Alright guys, i have tried everything, even resorted to tying one end to a fence post and the other to my car and still no movement. Any more suggestions?

If it won't respond to overnight loads and the warm up the carbon whilst the alloy is still frozen treatment I suggest above then you are pretty much stuffed. I suppose one could could try dissolving the alloy out with hot sodium hydroxide solution but I submit this should only be done by qualified chemists... Very easy to end up with some very serious injuries up to and including losing eyes... You'd also probably lose or at least weaken any other metal parts eg rivets.

If you are at destroy the bottom section stage then just saw it lengthways up to the join, and then see if you can extract the alloy from there, but frankly if its this stuck I'd leave well alone!

Edited by JimC

Originally posted by RS600653 But I'm a bit confused by the post quoted above, surely if the ali contracts more when it's cold than carbon it will result in a tighter grip on the carbon?

No, because these are tubes, and the alloy tube is inside the carbon one. So if you make it very cold the carbon tube might contract say to 1mm less diameter and the alloy tube say 2mm less diameter, so it gets looser. If you warm the carbon at the same time as chilling the alloy then the differential becomes even greater, because the carbon diameter increases...

I'd be inclined to tie the mast between two trees and leave overnight with loads of tension on, and then first thing in the morning warm up the carbon with warm water whilst whanging on even more tension. A spanish windlass might be convenient for getting the load on... I would be very wary about too much torsion as carbon sticks aren't particularly strong in torsion.

Edited by JimC

Another way is to dissolve the aluminium ( using a more powerful chemical than the slightly acid in coca cola ). Warning - this can be very dangerous!!!  
Use caustic soda ( drain cleaner ) crystals dissolved in water. This eats the aluminium away, and can get very hot - so be careful! There was a home-made cherub carbon mast stuck on an alloy mandrel, the caustic soda got so hot it boiled and there was a fountain of boiling soda and hydrogen gas coming out of the top of the mast.

It worked though, with no damage to the carbon/epoxy.

carbon and alloy?
you are right, the alloy will expand more, under heat (plus i would recommend more heat than boiling water anyway, but that is irrelevant).

Freezing it might be worth a shot

The coca-cola is the best idea! or use a release agent of some time. But instead of using a tension method, try and use a torsional force, it will be faster. see if there are two holes in the mast somewhere, i.e. the shrouds or trapeze fixings, stick a long bolt through it, clamp the other end and then apply a torsional load to it. pour the release agent over it and leave it. then after a while reverse the direction of the torsional force. shouldnt take too long.thats how i would do it if it was me, but then i dont really know what it is you are dealing with hahaha.