You would get the best appearing weld if you TIG weld the joint. I have welded Axle housings (GM 12 bolt) using Crown's Royal 220Tig welding wire. This is a high Nickel content for welding dissimilar metals. Tensile Strength (as welded) 120,000 psi. Should be strong enough to hold fencing together. If you do not have acces to a TIG welder, Crown also makes Royal-220M for arc welders. You'll want to preheat the pieces if they are large for either welding type. If you cannot find Crown welding wires in your area, I would use a filler that has a high nickel content in a similar brand. Hope this helps.
