Last time I looked at working copper, there wasn’t really any solder
alloy on the market that matched the colour of copper. Since it’s
been some time, I was wondering if there have been any developments
in this area.
How about that brazing rod specially for copper to copper joints and
no flux is necessary? It’s pretty much just copper with phosphorus in
it as a deoxidiser, isn’t it, so it’ll be close to copper-coloured.
Johnson Matthey sell it as…
Remember: what we do with gold and silver solders is really called
‘brazing’.
I love to use copper to teach soldering with. The bright silver line
of the solder gives the students an obvious clue to seeing the solder
flow, something that is much more difficult on all silver projects
and must be developed.
If you want to hide the solder on a finished copper project, (and
this is where everyone will get twitchy with my trick) hold the
copper
with a steal tweezers in some very blue pickle solution. The steal
will set up a plating environment and coat the silver solder with a
thin layer of copper. Make sure there is no other silver in the
pickle!!! Or it will copper plate too.
The pickle will be fine again as soon as you remove the steal from
it. This only works with really blue pickle, freshly mixed pickle
does not have enough copper in suspension to make the plating work.
When working with copper, the following steps is one method to
achieve a minimal line of solder in brass, copper or bronze.
Choose a sharp edge hammer, such as a riveting hammer (good for
this process, silly to make rivets)
At the edges of your copper, prep the seams by striking the
hammer as to create a “coin” edge effect and flaring the edges
outward. Visualize a slice of mushroom, with the rounded top cut off.
With a bastard mill flat file, make one solid file stroke. This
action creates tiny grooves for the solder to flow and flattens the
edge for maximum contact for your solder operation.
Solder the edges together. The grooves created by the file, allow
the solder to flow evenly into the channels. Once soldered, file your
copper, from one end over to the other. The flared portion of the
copper allows for extra metal to be moved up and over the seam, thus
minimizing the solder seam and making it nearly invisible.
Consistent color patination, as Nan recommended is achieved by
increasing copper saturated pickle which is often seen as a deep
blue. Take a portion of this solution, and add steel (great eco step
for used steel binding wire or broken sawblades) to the solution. The
salts in the sodium bisulphate (pickle) acts as plating bath and will
cover your solder seam with a light coating of copper.
Note, this is a tender and fragile plating which does not hold up
well to abrasives and should be one of the last steps in your
fabrication process.
Some solders can be plated very well, some not. It will depend on
the kind of solder you use and what alloy the solder contains. This
is a good time to put away your jewelry artist design hat and put on
your lab coat.