Just finished making one in TI for my exbit stove. Titanium foil from
http://www.titaniumgoat.com/windscreens.html then did a template in paper using
http://www.blocklayer.com/cone-patterns.aspx . You will need access to an A3 printer. Make sure you have the dimensions right to fit your stove and pot in the paper one then stick it to the foil and cut out with scissors. To join it together I bent an overlap of 10mm on each side (1 bent in and one out) and they hook together. Punch holes around the bottom with a normal paper hole punch and you are laughing. Roll it up and put it in the pot with a rubber band around it.