I finally hooked up (added a charger and ground rods) to the existing electric fence. It's a rope type fence with metal braided through it. Not sure of the brand. It worked ok. Is prefer a stronger zap but I think this will do for now. The fencer says its 2 joules.
Last night it rained and this morning I've got a few spots on the fence where its snapping loudly and you can see a spark. It also looks like its actually burning the rope part of the fence where its sparking. Some parts where its sparking look a bit rusty. Could it be the rust causing this? I unplugged the whole thing. Any ideas?
If the rope is clear of the posts and other metal objects you've got breaks in the wires woven into the rope. I don't think these can be fixed. You'll need to replace the rope or accept the arcing (and reduced fence effectivness).
Folks forget that rope ages and, in areas of freeze and thaw (whick cause the rope to contract and streatch) it's rather easy to break the internal wires. So it needs to be replaced on a regular basis (although frequency can vary).
This is also a problem of "tape" fences.
Replace the rope and you'll likely solve the problem.