Ray K wrote:
I tried disassembling a 1/2" copper elbow from water pipes, using a
propane torch that comes in a $20 Worthington plumbing kit from Lowe's.
The solder wouldn't melt. I'm wondering if the solder used around 1969
had a much higher melting point than what's used today. I did keep the
tip of the blue flame on the elbow, and I tried heating around all sides
of the elbow.

The house is part of a development of 600 or so houses, so I doubt the
builder authorized some expensive, high temperature silver solder.

All the water was drained from the pipe, and the end of the pipe that
supplies cold water to the utility tub faucet was disconnected from the
faucet. The pipe from the faucet to the elbow is 4". The other pipe into
the elbow is about 6 feet long.

Thanks,

Ray

Just cut the old out. Then you'll see how much water was really left in
there absorbing all your heat. Then when you get it drained for real,
you can proceed with the repair.