Decided i would check the gap on my X plugs and adjust them according to the Ford manual which states to adjust the side electrode to achieve the proper gap. Well, it seems the side electrode doesn't much like it when you mess with them, as mine just snapped off with very little adjustment or warning. Adjusting the X like an ordinary plug seems to bend the center electrode which is much thinner than the outer electrode. Which method is correct?
I have replaced the side electrode before. It can be done.
Bending the ground electrode is the proper way to adjust them. Using two pair of needle nose pliers (one from each side) without bending the point where it is welded to the base is the best way.
Often, with very little stress, the ground electrode will break off. I, too, have welded replacements onto the base.
The size of that electrode varied, even originally. It would affect the heat range of the plug, but should not be enough to worry about. Use a piece of appropriate size steel rod (small welding rod will do). The smaller the rod, the faster it will burn back in use, so don't go too small (more difficult to weld besides). Do not go quite as large as the thickness of the plug base either.
Drill a hole into the end of the plug base, barely large enough to slip the steel rod into (leave the rod long for heat dissipation reasons.
I use an oxy-acetylene torch, because that is what I have. The trick here is that the small rod will melt and burn much quicker than the base. Begin by heating the base over where the rod is inserted, directing the heat away from both the steel rod, and the porcelain (if you are crazy enough to try this without taking the plug completely apart). As the base exceeds cherry red, move toward the new electrode rod with your welding rod and puddle them together.
Brazing would be easier to do. But I have never been willing to trust it inside the combustion chamber. The expected temperatures say it should work, but are too close for my comfort.
Some sort of wire feed welder may work better, but I never had one to try it with.
I have replaced several base electrodes this way. I think I ended up destroying one plug before I figured out the balance of directing the heat. My first try, I got perfect. After the one I ruined, I have been more careful. I have run several plugs for a fair number of miles this way, with no troubles from them so far.
Original X plugs side electrodes can take adjusting, repros sometimes not. Do NOT attempt to bend the center electrode, you'll likely crack the porcelain.