marbles wrote:
Some copper water pipe solder fittings have a residue of green gunge
around them, due to the finished solder joints not being effectively
cleaned after soldering.after new CH installation around 5 years ago.

First Q: What is the green gunge (chemically)? Does the deposit have
common or garden name? It must be a Cu compound, but how is it formed
from solder flux, copper, solder & propane gas used in the torch?

I'd say ots PROBABLY copper carbonate...sort of natural end point of any
copper type oxide and CO2..

Second Q: What is the most effective method of cleaning it off,
especialy when it has been on the Cu pipes several years? I'd like to
get the area around the fittings reasonably chemically clean. I fancy
just cleaning with wire wool might leave a residue for the green to
re-crystallize on.

Ni. The reaon its around the joints is they they have a flux residue
usually. And have been heated. If you WASH the joint and then wool it
up, it stays good, usually


Third Q: I thought I had cleaned the joints at the time, so how should
soldered work be cleaned to avoid green film formation?

Darned good washing and some wire wool

TIA