chains is one of the two most often preformed jobs in the shop. (Sizing
rings is the other) The difficulty of chain repair lies in the fact that
the chain is made up of fine wires. These wires heat up quickly when trying
to melt the solder. Two problems develop. The first is if the wire link
gets too hot, it will quickly melt as you are trying to solder. When a
link melts it forms a small ball of gold fused onto the next link. This
of course melts forming a larger ball on the next link. This then melts
forming a larger ball, etc. It is a chain reaction.
The other problem is, if too long a section of chain is heated the solder
will flow from one link to the next. From there, the solder will flow
to the next link on down the chain. It is that chain reaction thing again.
This will cause several links to solder together forming a stiff place
in the chain.
Both of these reactions by the chain result in an un-satisfactory repair.
Jewelers have devised many ways to over-come these problems. They include
coating the chain with an anti-flux such as yellow orcher or white out,
and covering the chain with a heat sink such as a washer, razor blade,
or coins. My preferred method is to use paste solder and to master the
art of torch control.
The method to repair a chain using paste solder is as follows.
Inspect the Chain
Look over the chain to ascertain how the links are put together. In order
to re-assemble the chain where it is broken you must know how the links
are assembled. At this time look for other areas in the chain that need
repairs. Although the salesperson taking in the repair should have already
done this, it is a good idea to double-check their work
Remove Damaged Links Trim off any damaged links from the broken ends of the chain
Cut End Links The end link needs to be cut in order to re-assemble the chain. Some chains
require you to cut one or two links on each side. The number depends on
how the chain is assembled. You can cut the links with a fine saw blade,
small end cutters, or a cut-off wheel in your flex shaft.
Re-Assemble the Chain Lay the chain on a clean ceramic soldering board. Using your tweezers
fit the two ends of the chain back together. Then squeeze the links closed.
Once assembled it is often difficult to find the break in the chain. To
help you find the break, mark the broken links with a felt tip marker
before assembly. On some chains like rope chains you can add the solder
to the broken link before assembly.
Another method to help you locate the break in the chain is to cut a
line down the center of a ceramic soldering board using a cut-off wheel
in your flex-shaft or with the edge of a diamond file. Then, lay the chain
on the soldering board placing the broken link over this line. With this
method you can layout several chains about 1" apart. Then start at
one end of the solder board and solder the first chain, and then proceed
to the next one. With all the chains laid out, you can quickly solder
each one and the line shows you where to solder, with no time wasted trying
to find the correct link.
Add the Solder Apply a small amount of paste solder to the joint. Do Not coat the chain
with boric acid. The flux in the paste solder is all that is needed for
the solder to flow. The slight oxidation on the chain from the heat will
help keep the solder from flowing to the other links.
Heat the Chain With a small pointed (oxidizing) flame heat the ceramic soldering pad
next to the joint in the chain. Do Not use a bushy (reducing) flame as
you will heat too much of the chain. On most chains, you will not need
to place the flame directly on the chain. Place the flame on the solder
pad and let the reflected heat melt the solder. This will help you from
melting the chain. On larger chains, heat the solder pad on one side of
the chain, then quickly move the flame across the chain to the other side.
Heat the pad on this side and then move back across the chain. Repeat
the process if the solder has not completely flowed. However never direct
the flame on the chain for any length of time. Move it quickly across
the joint and heat the solder pad allowing the reflected heat to melt
Clean the Chain When cool, hold the joint of the chain on your bench pin and clean off
all flux and oxidation with a scratch brush. A brass brush or a small
satin finish brush in your flex-shaft works well. The new 3M Radial Bristle
Disc are excellent for this purpose. I prefer the blue wheels and stack
4 to 6 on my mandrel at one time. Pickling the chain before doing this
can help, but is often not necessary.Polish the Chain DO NOT Polish Chains On A Polishing Machine. I do not know of any other
procedure in the shop that has cut and broken more fingers than a chain
becoming tangled around a polishing wheel. (Not to mention the expense
of replacing a customer's chain.) Polishing machines loves chains. They
eat them up. Come near a polishing machine with a chain and it will snatch
it right out of your hand and wrap it around its wheel and arbor.
To polish, lay the chain across your bench pin. Then hold the chain down
tight with your thumb and index finger. With a bristle brush in your flex
shaft polish at medium speed the area of chain between your thumb and
finger. Polish the chain little by little in this manner. It is a safe
and efficient means to accomplish the task.If properly repaired, your customer will return with a different chain
for you to repair, and then a third. Eventually they will return to purchase
jewelry. Now, that is chain reaction we can all live with.