I had a chance today to repair a little fan dipole that I use on 20 and 17 meters. I ended up using the 4" length Fi-Shock high-voltage ribbed insulators mentioned to me by Peter N2IDU. I was very impressed with how rugged and rigid the material is. Construction was easy and fast:
1. clamp each insulator into a vise by one of the ribs
2. Drill a 1/8 inch hole at each end for the wire
3. Use a pair of wire cutters to slot each hole to the end of the insulator
4. Snap them onto the parallel wires and space them evenly
5. Walk along with a hot glue gun and fill up the end of each insulator
The end result is really strong. I'm going to re-do my open wire line with these things when I get a couple of sunny days in a row. The insulators cost less than 20 bucks for a box of 200.
http://www.fishock.com/store/high-tensile-electric-fence/500-540Rob W1AEX