In reply to minexplorer:
I just use . . . . . . . wire! I don't even bother with the plush plastic coated stuff Chris shows on his website. Buy the gauge that fits the holes ( I can't remember what it is) from a hardware shop (used to be called an ironmongers). You get a great big reel - enough for several lifetimes of broken cam wires - for about £1 odd. I first tried thinner wire to get more flexibility but it broke , which is why I'm suspicious of e.g. strimmer or fishing line.
I've been doing it for years for self and mates - never had to re-do one yet. The only slight downside is the wire sometimes distorts a bit in your sack (the bigger the cam the more likely) but you just have to manipulate it a bit as you rack it.