Melting point of solders and copper tubing

Hi. I’ve heard that solder that has already been used on a joint
melts at a slightly higher temperature if exposed to heat a second
time. Any truth to this rumor? Can anyone recommend a source of small
diameter, telescoping, copper tubing for making jewelry hinges?

Thanks.
Peggy E. Pollak, Ph.D.
Senior Lecturer in Botany
Peggy.Pollak@nau.edu

Peggy

I can’t quote a book reference off hand and my knowledge of the
metallurgy involved tends to be empirical. I use mainly hard solders,
older joints just don’t seem to remelt or move without a lot of
effort. Easy and even medium solders are different, too much low
alloy in the mix I believe. Usually easier and better to avoid using.

If you want heavy wall copper tube one source is to pull down BC"
tubing (local hardware store) A boat winch draw bench makes the job
easier, and you might need an internal mandrel to reduce the wall
thickness. With some care it should be possible to make telescoping
sizes.

Jeff
Demand Designs
Analog/Digital Modeling & Goldsmithing
http://www.aztec-net.com/~jdemand

Find a hobby store that sells supplies for model trains. They
usually stock brass and copper tubing in many sizes as well as
sheets in thinner gages.

Marilyn Smith

I have found that my local model train shop has a number of sizes of
copper tubing which I have used for hinges and rivets. Batya