Article: Special Repair Work

By Prof. Dr. Erhard BrepohlMore from this author

It is not uncommon for moving parts to wear out. This is to be expected because of increased friction as parts rub against one another. A common example can be found in connecting rings such as the jump rings that attach a charm to a bracelet or a pendant to a chain.

Special Repair Work Mechanical Repairs

If a section of the ring is worn thin it is usually best to discard the old ring and replace it with a new one. Circular rings are preferred over ovals because they rotate naturally during use and distribute wear around the entire loop. Wherever possible such loops should be soldered closed.

Another common repair involves springs that loose their tension over the years. This might be due to several factors, ranging from something as easy as a bent part to something as complicated as annealed or broken springs. Before undertaking any repairs to a moving part, study it to be certain you understand the mechanism. Consider every possibility - What will happen if I file this away? If I tighten this rivet? and so on - before trying anything. Not only is the process thereby made more efficient, but you avoid the risk of replacing one problem with another!

Each situation deserves unique consideration, so our comments here must be general. If a rivet must be removed, file the head off one end and use a needle to push the rivet free. Do not try to reuse this wire, but replace it with the same gauge.

Always try the simplest solution first. It might be possible to renew springiness simply by bending parts into tighter curves. If this doesn't work, try rehardening a piece by bending and straightening or by lightly planishing it. Continue in this way, each time checking your results to see if the problem has been fixed.

Brooches

The following details will be found in a properly made brooch. Where any of these is not the case, the repair task is obvious.

1. The pin must easily move without rattling.
2. The pin should open at least 90 degrees.
3. The pin must securely fit in the catch with enough tension so that it is securely fastened.
4. The pin stem should be straight and pointed so that it easily penetrates clothing by pushing aside the fibers rather than snagging through them.

If the pin has gotten bent, use flat pliers to straighten it or lay the shaft on a flat steel surface and tap it with a small hammer or plastic mallet, taking care not to create unnecessary hammer marks. To complete the repair, tap the rivet at the joint to make a tight fit and burnish the tip to restore its shape.

If the joint unit has come loose, the pin should be removed before the joint is reattached so it does not get annealed. Of course stones on the front of the brooch will also need to come out. When soldering on a safety catch (also called a ball catch), avoid using too much flux or solder because they might flow up into the mechanism and seize it. For the same reason, direct the heat mostly on the brooch, remembering that solder will flow toward heat. In this case you don't want the solder to be attracted to the pin catch before it has had a chance to spread itself out on the brooch. The moving part of the catch can also be protected from being soldered by applying a drop of oil with a needle between the walls.

In cases where the brooch cannot withstand the heat of soldering, prepare a piece of sheet metal that will integrate with the back of the piece, using sterling, nickel silver or brass to match the piece. Solder the pin joint and catch onto this, then after cleaning it, use glue or soft solder to connect it to the pin.

Chains

Most repair shops will agree that the most common job they see is the repair of chains. Not only are these subject to a sharp tug, sometimes by a child or by accident when taking off a jacket, but they also consist of nothing but elements that constantly rub against each other. Especially in the case of delicate chains, it is only a matter of time before the links wear thin.

A good repairman will start by examining the chain closely. If many of the links are worn it is probably useless to make the repair - the chain will just break again soon at some other place. Take the time to show the worn links to the customer and allow them to reach the inevitable conclusion themselves.

When repairing a chain, isolate the broken link with a needle or locking tweezers and lay it open so its ends can be properly prepared for soldering. Though the joint is small, or perhaps just because it is so small, it is important to follow the rules for soldering fully. If you can locate the solder joints in the adjacent links, turn them in such a way that the solder does not touch any other link.

Lay the intact chain on a soldering block, perhaps marking the location of the joint by drawing a line across the block, and apply a very small chip of solder on the joint. Solder with a pointed flame. Commercially made chains use special wire that has the solder - typically a very low melting alloy! - inside the wire itself. This explains why even a 14K (Au 585) chain seems to crumple at what seems to be a usual soldering temperature. Always proceed cautiously and use the lowest temperature solder available.

It is also possible to protect adjacent links with an insulating material like yellow ocher or soldering investment, but most professional repairmen disdain the practice. It is tedious and as often as not, useless. The protecting material flows into the intended joint and prevents the solder from closing the link. In the end your best bet is to prepare the joint well and pay close attention when you solder.

It is often the practice in repair studios to work on several chains at once. There is something about the scale and sensitivity of the repair that suggests that once you get into the rhythm, you should stick with it. If several chains are laid out on the block at the same time, remember to mark each with a tag so you will be able to return it to the proper repair envelope!

Bracelets

Many repairs deal with closures. When a box clasp no longer holds, it is usually the result of the tongue having lost its elasticity. The problem can be quickly but only temporarily solved by putting a knife into the tongue to raise it; after a short time the problem will reappear and the tongue can easily break off.

It is better to grasp the end of the tongue with flat pliers and bend only the remaining portion of the tongue upward with a knife; this will protect the tip from breaking. If the tongue is broken it is best to replace it with a new one. Soldering it together will cause the metal to be soft. In this case it will be necessary to work harden the piece by hammering so that it will obtain the necessary springiness. In some cases the tongue is large enough to allow the parts to be riveted together, in which case the original springiness can be retained.

Just as with necklace chains, link bracelets are subject to wear as the elements rub against each other. Again it is necessary to examine the bracelet to determine if a single loop is at fault or if most of the links are worn thin. The former case allows a link to be strengthened by soldering a bit of extra metal to the thin spot; a worn chain should be replaced.

There is a style of bracelet in which the sections are held together by a hinge. If the bracelet has been well cared for, these hinges can last several generations before showing wear. Of course some people are harder on their jewelry than others, and a hasty or clumsy person can put a lot of stress on a hinge by torquing it sideways.

If the hinge is simply loose, it might be possible to tap on the ends of the rivet pin to tighten it up. If the hinge is broken or the tubing worn through, the entire hinge will need to be rebuilt from scratch.

Excerpts from the book:

The Theory and Practice of Goldsmithing
By Prof. Dr. Erhard Brepohl
Translated by Charles Lewton Brain
Edited by Tim McCreight
Brynmorgen Press
ISBN 0 9615984 9 2

Prof. Dr. Erhard Brepohl

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