In reply to John Ww:
Done it for you...
From NeedleSports friends & cams page...
"Marlow - 5.5mm Dyneema Cord x 1 metre
Static cord that almost as strong (15.89kN) as 9mm rope. Use it for restringing nuts etc to save weight and bulk, but tie a triple rather than a double fisherman's knot (if you don't know the difference then ring us up and we'll explain!), and also you must cut it with a hot knife, pull the sheath back 5mm, chop this amount from the core, pull the sheath over the end of the core and heat seal it in place - you need to do this because the core and sheath do not bond together when cut. Colourful Black only."
A couple of years ago I replaced tapes on three WC friends using the stuff above.
I found the 1m length too much so cut them down further, which is not easy unless you have a very good blade or hot knife, so maybe get them to do this for you. If you're tall and/or don't mind stuff swinging low on your harness then this might not be an issue.
To make sure the triple fishermans were never going to slip or work loose I preloaded them, clipping the knotted slings to an overhead beam and then bouncing on them with bodyweight.
Reslinging as above works okay - I've fallen on all my reslung friends and they were fine - but maybe it's something not worth doing and you might be better off leaving your friends as they are. I don't know how old your friends are, but even if the slings have lost 50-60% of their original 22-24kN strength (after say 10-15 years?) they are still very strong, stronger than some of the other gear you're probably happy to trust. For further info see strength tests/results for old friends and slings easily found online, e.g. BMC technical reports, KP at BD amongst others. The original slings are much neater than knotted dyneema replacements, as well as the sizes being more easily identifiable by sling colour.
With hindsight I don't think I'd bother replacing nylon slings again. By the time an original nylon sling is weak enough to worry about I'll probably be more concerned about other parts such as the wire stem and be happy to replace the whole unit anyway.
