On Thu, 11 Jun 2009 15:19:37 -0500, Richard J Kinch
wrote:

Well, now here is an update where the owner has cleaned off the corrosion,
showing some sound remnant metal, with the joint being apparently copper to
copper:

http://67.207.131.7/poolheater2.jpg

Here is an idea I had: could one not just wrap this snug with flat copper
braid (like copper grounding strap stuff) and then fill with braze, like a
solid metal "bandage"? Or even wrap with copper wire and fill?

Otherwise I am thinking a sleeve machined to fit closely over the remnant
geometry.

In any case, brazing will require opening this joint, cleaning off the oil
residue, reassembling with repair parts, filling with inert gas, and
finally heating to braze temp. Then evacuation and recharging.

Pressurize and get out the test soap - figure out exactly where it
is leaking. You do NOT necessarily have to take the old joint apart
if it's basically sound.

If it is a cold braze joint and a channel opened up in the gap after
time passed - take it apart, clean it up, and re-braze it.

If it is a leak in the stub and not a bad joint braze, and I was
making a patch for this, I'd just slit a section of copper tubing and
slide it over the leak Put the copper wire wind layer over the patch
to mechanically hold it, then braze it in place.

-- Bruce --