Pressure tank leaking AARRGGHHH !!!

Ok here goes.
Welltroll challenger series tank. installed in 2001.
A few months ago my pressure tank started leaking. I cut the 1' line, pulled the tank and found a pin hole in the cast iron elbow.
Simple enough. I drilled out the hole, tapped it for a 4-40 thread and screwed in a stainless steel screw.
2 months later (Yesterday).MORE WATER.I cut the line, pulled the tank and although my original repair held. There are now two more holes on the other side of this 1 inch cast iron elbow about 2 or 3 mm in size. A couple of pieces of thick rubber placed over the area and a SS hose clamp fixed it (for now).
The puzzling thing is that this piece seems to be wearing out from the inside and it is welded on to the tank and doesn't look like it can be removed.
I'm pissed because if there are pin holes in the casting and these are letting loose isn't that a manufacturers defect ??
Things are tight and I cant afford to buy a new tank. Can this one be repaired.
I assume this is cast iron as that it looks like a regular 1"elbow can this be welded or braised or SUPER PUTTIED hahahaha!!!how about JB weld.
Any body have any tricks or ideas. I would be afraid the heat the tank up to pull off the old elbow...HEEEELLLP.

Tank Leaks



Get a hold of AMTROL on mon, or tues, when they are next open
they should have somekind of warrenity on this they can best tell you
this. be ready with the following information.

model #
serial #
date purchased or installed
it may also be helpfull if you can take some pictures to show their tech. engneers. by e-mail

GOOD LUCK MACPLUMB 777

Most tanks have a 5 year warranty but... the holes are either from erosion corrosion wearing holes in the galvanized, not cast iron, elbows or it's caused by aggressive water rusting through it. that would be from low pH acidic water or high DO or CO2 content. Bacteria can also cause pinholes.