"Usual Suspect" wrote in message
...
On 15 Nov 2005 13:11:32 -0800, wrote:
wrote:
I'm trying to make a sculpture out of coins..... I'm going to be
soldering the coins in a tube for fingers....doing the individual
finger joins in cylinders.
Why not use epoxy instead of solder to bond the coins?
Epoxy has lousy shear strength. Furthermore, it tends to get brittle with
age. You can use epoxy for joints that are unlikely to be stressed. Not
for this application. Besides, it would look ugly.
There are several techniques for holding the parts while you solder. In
your case, the first thing to use is a charcoal block. You make curved
slots into which to place the edges of the coin. Say you need three coins
to complete a circle. Put the three coins in the slots so they touch. You
will also need some binding wire (soft iron wire and charcoal blocks are
available at any jewelry supply store). Lightly put the iron wire around
the three coins, firmly, but not so tight that squeeze the pieces together.
In your case, I would also put a small plug of charcoal at the top of the
three coins to prevent their caving in. Be careful to put flux only at the
joints you intend to solder and use only very small pieces of solder. The
solder will not attach to the wire.
Once you've got the base done, just use binding wire to attach the
next three coins to the cylinder.
With copper, the problem of undoing previous joints is not severe.
With silver, it would be quite difficult. One way to prevent this, should
it be a problem, is to put the starting ring in a small pool of water.
Jeweler's typically use their dapping block for the purpose.
The above is what you would do if you were doing this as a one-off
project. If you wanted to do a lot more, e.g. production, you should look
into resistance soldering or spot welding. Either will require an
investment of several hundred dollars.
\
Boris\
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