What diameter and length of cord/spectra cord should be used to make a cordelette?
7mm perlon or Spectra cord is typically what a cordelette is made from, in 18-20 foot loops. This should give you plenty of room at the
belay to rig an equalized anchor.
Maxim has come out with a new product called Tech Cord that is 5mm and actually stronger than Spectra. It was originally developed for
the military to rappel on 3mm size cords. They are marketing it to the climbing industry at 5mm and they say it is strong enough for
threading hexes and making a cordelette. The price is $1.00/foot, kinda pricey. It was reviewed in the latest Climbing Magazine.
There is another product from Mountain Tools called the Web-o-lette. It is a 10 foot length of Spectra webbing with loops sewn into it at each end. It is a really nice option to a cordelette. You can see our review here.