In reply to SethB:
Thanks everyone for suggestions. After further experiments I've now got what seems like a practical solution under 'lab' conditions (i.e. domestic freezer at -20 degrees having worked as much water into the joint as I could). Not yet tried in the wild but I can't see why it'd not work ok.
You need a small loop of wide, strong tape - I used 25mm flat nylon, having snapped a thinner tape, and not getting enough purchase with prussick loop type cord (although I imagine it could work sometimes...). By 'small' I mean about 10cm laid flat or less. I used a simple overhand knot to make the loop. I plan to leave the loop in the pole storage bag. The same effect could come from any tape - a sling or actual belt - although much length will be a nuisance, and I'm not sure a knot used to shorten it would then be easy to undo. Finally, the handle loop is an obvious option if strong enough - the Leki ones use a skinny tape I'm suspicious could be snapped by what I'm describing, and I'm not prepared to test mine to destruction. I've asked Leki if they'll do so, and if they do, I'll post the response! I think BD handle loops are strong enough although not 100% sure stitching couldn't be damaged? Note that to do this, you obviously need to loop them over the handle itself so it's effectively a separate loop for the purposes of this technique.
Anyway, it's as simple as using the loop as a tourniquet to grip the un-grippable frozen bit so tightly it can be twisted:
- Insert the 1st pole section into the stuck section (which is just a freezing slippery 2cm stub at this point..)
- Put the loop over the pole, wrapped flat around the stuck stub and the joint
- Into the loop insert ice axe handle, handle of the other pole, large krab, rescue knife or anything else strong
- Twist until it's tight (*really* tight - as I said, I snapped thin tape whilst experimenting!) (nb the ferrule inside the point where the tape is so I had no concerns about crushing the pole - same comment does NOT apply to using pliers or similar to grip...).
- You've got the pole handle in one hand the ice axe/whatever int he other and this grips well enough to twist the frozen joint apart. It was definitely easier with a big long thing - handle of the other pole worked best of all - but still possible, if awkward, with a snap gate krab or spatha knife.