Basic Jewelry Construction and Soldering Principles
A short review of jewelry construction and soldering principles would be a good idea at this point. They’re fairly basic. Principles of soldering (or what most of the world terms ‘brazing’ but jewelers call ‘soldering’) include: make sure that all joins are recently scraped, cleaned, sanded, or otherwise bared; that you can’t see light through a join; that you use tons of flux-I’m a firm believer in “you can’t have too much flux.”
On gold, this is much less important; gold doesn’t oxidize very easily, so you can use Batterns and Pripp’s self-pickling fluxes on gold without much worry, but if you’re going to be working with sterling silver, or base metals, then definitely use a lot of white paste flux. Non-fluoride fluxes are recommended. You heat the metal, not the solder. Generalized heating works pretty well. You heat the larger part, not the smaller; you allow the heat to go into the smaller part from the larger part. If possible, you pre-melt solder onto the smaller part, so that as the heat rises into it from the larger part the solder is sucked down onto the larger part from the smaller.
It is often a good idea to bounce the flame onto the metal off the soldering brick. I do this quite often by using a nest; I have a small bundle of very thin-not thick-iron binding wire under the piece being soldered which lifts it off the brick and allows me to bounce the flame off the brick and up onto the piece from beneath. Always keep your flame moving; never keep it still. There are some exceptions to this; for instance, if you are a professional using a mini-torch, which heats locally and can allow you to heat up just the spot that you wish to flow, yes, maybe you hold the flame still, but most of the time, you keep the flame moving, particularly with larger flame types such as from an acetylene/air torch (like a Prestolite torch).
I use a titanium pick to plant my solder most of the time. I will cut small chips, pre-flux the chip, use a bent titanium pick, and will heat the pick, then touch it to the fluxed chip. The chip sticks to the pick, I move over towards the piece, heating the chip on the pick. It balls up and rolls down to the end, and then I plant it onto the piece and go back for another chip. You can obtain titanium wire from Reactive Metals Company or sometimes for free from bicycle shops in the form of a bent titanium spoke. The reason for the bend is that you can’t see what you are doing with a straight pick-you can with a bent one. A bent pick also lets you pick up items and move them around without having to put down your pick and get some tweezers.
I like to use small solder balls because they leave less mess when they melt. You have to, of course, be careful not to boil all the good stuff out of the solder ball when making it-the moment that it turns into a ball, get the flame out of there. Set up your solder area up in a logical manner so you don’t have to pass your hand through a flame to get to something, and make sure that all movements are organized and sensible and smooth when you’re working. The same principles should apply to your workbench and to your entire working space.
I believe in the use of binding wire quite often in solderings that have to go right. Traditionally, goldsmiths are sort of macho, and you’re expected to free-hand everything during soldering, which is fine in a production situation, where you’re repeating the same act over and over and over again and so get very good at it, but it’s perhaps a little less useful for a one-off construction job, and so I think it’s well worthwhile taking the time to wire things up with thin iron binding wire. Sometimes ten minutes spent wiring something will save you half an hour of dealing with the mess that would have resulted if you hadn’t done it. I prefer thin twisted cable to a plain wire. Twisted cable does not burn out easily like single strand does and can expand and contract past itself when heated thus decreasing the likelihood of pinching into the work while soldering and denting it. One never uses wire thicker than the sheet being soldered for this reason.
The use of tension loops is also important. The twisted wire cable is then looped every 1-2 cm and twisted to make rows of tension loops. It is important to always twist them in the same direction so you don’t inadvertently loosen them later at the wrong moment. They may be tightened and allow stress to be spread through the binding system so the wire doesn’t give way suddenly just as one gets it tight enough. They also permit more complex wiring situations.
It is important never to wire across open spaces as the metal softens and will bend inwards and collapse. Instead one uses hooks and the presence of tension loops to be able to re-direct pressure against the strongest structures of the object being soldered. Because everything becomes soft and pliable when hot we use structural strength to replace material strength at the temperatures required for soldered construction.
When bridging a seam with binding wire take thicker wire (16 gauge (1.5 mm) and up) and make a bridge to lift the binding wire up off the seam. This prevents it from being soldered down to the seam. Notice how the bridge wire loops up and away from the seam to avoid contact with it and also how the ends of the thick wire bridge are also bent up away from the metal surface being joined so that like the skids on a sled they do not scratch the surface they are on.
You don’t need to pickle every time you heat the metal; you can take your metal and put it into a cup and turn the hot water tap on, and this will wash away the flux in a few moments, and then you can continue with preparing your next solder job. In terms of construction principles, some basic ones are: think about structural strength; think about stress and use; assume that the client will do their absolute worst in terms of bending, yanking and twisting your jewelry object.
If you do this and plan for it (sometimes called overbuilding) you should be all right. Other construction principles include: wherever possible, use cut-and-slot construction, rather like paper dolls; wherever possible, use scoring and bending-I score and bend using a separating disk and follow with a file to give an exact bend; wherever possible, make the part out of the largest piece of sheet you can. Work on a small part as long as possible while it is attached to a much larger piece of metal. This will serve as a handle. Always leave handles on small parts as long as possible to make it easier to work with them. If possible even finish them while attached to a handle. The last thing you do is to cut the part off the handle.
Don’t make something out of ten pieces of sheet if you can make it out of one piece of sheet that you’ve scored and bent, cut-and-slot into. If you want several parts of your finished piece to be related-let’s say a box, for instance, where you wish the lid portion to be the same size and shape and match up to the bottom portion-make them out of the same piece. This is a very important construction principle: If you wish things to be related, make them out of the same unit, cut them after you have constructed your shape or unit.
Scoring and bending tips
Scoring and bending is one of the most important ways of constructing jewelry. Scoring is a method of obtaining very sharply defined bends in metal sheets. The angle of the bend is determined mainly by the amount of material removed from the groove. It allows rapid and accurate work to specific angles and parts being soldered stay in place during heating without falling apart. The grooved cross section can be arrived at in numerous ways, my favorite being separating disc followed by needle files of the appropriate angles.
No matter how one makes the groove for scoring you get essentially one chance to make the bend which is then flushed with solder. If you score and bend and find that your angle was not correct all is not lost. Flux the clean scored bend. Anneal. Place in hot running water to get rid of the flux (not pickle!). Bend it gently back flat without overbending at all. Complete any additional scoring that has to be done without stressing the bend. Reflux, anneal, remove flux in hot running water again and bend up. You only really get one chance to do this kind of thing. Note the insistence on hot water instead of pickle. This is because pickled surfaces do not take solder well, do not induce solder to run into seams and do not fill well. You don’t ever want to lever back and forth on scored seams hot or cold.
Silicon carbide separating discs are superb for scoring metal for bending, particularly when the metal sheet is less than 4 or 5 cm across. I also use them for creating the groove on the edge of a piece of sheet metal to fit a tube for hinge making. One usually follows up a groove made with a separating disc with the appropriate angle of needle file to get the bend you need. While I was originally taught to use discs for catch building which involves only straight lines I discovered that they are superb for curved line scoring. Advantages include no disturbance of a textured sheet metal front surface while gaining enormous changes in plane. This is how many of my own pieces are done.
Basic tips for scoring with the disc include: anneal the metal before you begin. Do not press hard; if the disc wears quickly you are pressing too hard. The disc is very hard (nine and a half-it will cut ruby and sapphire) but brittle. Let it cut its own way. Wear safety glasses and breathing protection-the dust is not good for you. Let the disc drift gently away from you (right handers), if you pull it towards you it will tend to sink rapidly through the metal. Go over the same area a number of times. Because the disc wants to leap over the edge away from you and come back on the other side lift the disc off before you arrive at the far edge and turn the metal around so the part near the edge is towards you before continuing. When you see a raised line on the other side it is time to stop. If you go through burnish it closed before soldering. Remember to always wear eye protection when using these discs.
For exact bends one follows up in the same groove with the appropriate angle of needle file (triangular followed by careful use of a square one for a 90 degree bend). A separating disc is very good for cutting tubing (don’t hold it too close-the metal gets hot), particularly at angles. One can for instance notch tube rapidly with a disc and then bend it and solder it. I also use a separating disc as a file sometimes on metal. Remember to always use eye and lung protection with them.
Simple is best (least moving parts is best)
One of the important principles for mechanical constructions and especially moving parts in mechanisms is to keep it simple. One usually begins with a far too complex design and in order to get something functional one has to boil it down quite a bit. Simple is best; least moving parts is best. Because our metals are inappropriate for the mechanical stresses that we often expect them to bear, if you have a lot of moving parts, things tend to wear out more rapidly.
There’s much more to go wrong. So in designing a linkage system or a hinge system, or a construction problem, keep it simple. Boil it down. Take your initial design, which may consist of many parts, and keep distilling it down until you have the least number of moving parts possible. This will help things last. You can see Celtic torcs that are designed so there is only one moving part, and they’re still around, thousands of years later. So, again, keep it simple; reduce the number of moving parts as much as possible.
Designing your own system
The highest form of good mechanics comes during the design of one’s own versions when one designs mechanics that are specific to the aesthetic and design problems of the piece. Learn the generics presented here and then go on from there, applying their principles. An experienced designer goldsmith will draw the piece out without thought of how to deal with the mechanics. Only after the design is drawn out does one begin to think of how one will actually do it. The previous comments feed directly into the kinds of issues that arise when you wish to design your own mechanical systems.
Whatever you think of at first is too complex, unless you happen to be particularly brilliant. That at least is my experience. Draw things out, look for models, look for existing examples where other people have already solved the problems that you will be setting yourself. One of the interesting places to look for problem solving for soft, weak materials, is in plastics construction. So if you look at plastic toys and bottles and boxes and plastic objects, you will often find many of the construction problems addressed that jewelers have to deal with. They’re after maximum strength, minimum material. Draw everything out, and make samples, at least small bits and pieces of the trickier parts of what you’re planning. Unless you’re an accomplished goldsmith, it is recommended that you use a proper plan, that you write down the steps involved in doing the construction, at least in point form. This will help keep you out of trouble.
If working intuitively in creating one of a kind art work instead of going from drawings and developed ideas then one still should make samples and at least the occasional working note to solve problems and create hinged objects most effectively.
It is very important to work safely and in a safe manner, and to set up your studio and your workshop so that you do not expose yourself to chemicals, fumes or dust more than necessary. It’s a very sad and shocking thing to see friends who, after a number of years of working as goldsmiths, are debilitated, unable to hold things or hammer, perhaps on oxygen, or otherwise damaged. I knew someone once who became so sensitized to the metals in her studio, when she worked her hands would crack and bleed and she had to leave the field. You don’t need to throw away your career, and your life, simply by not thinking, and from not acting safely.
It is well worthwhile doing a safety evaluation of your workspace, and I suspect that if you do this, looking out for dust and fume exposure, chemical exposure and so on as well as unnecessary procedures that can be replaced by a safer alternative, that you will find, in your own workspace, that you can make at least five or six changes that will improve your safety conditions. It is worth noting that the jewelry industry is the only modern metal working industry where there is not a yellow line on the floor at the door to the workshop. In the metalworking industry one does not cross that yellow line without eye and hearing protection.
It should be that way for jewelers as well but our traditions get in the way-think about it, we need to make safer workshops based on contemporary knowledge of chemicals and processes and not just work the way we were shown to do. When I started as a student in 1974 we had a bucket of loose asbestos fibers under the bench that we would grab and moisten with water to hold things for soldering. To do such a thing now would be unthinkable. As goldsmiths we need to continue to improve our working conditions and the safety of our shops.
Our field in general tends to adopt techniques and production methods late, examples include: dentists had flex shafts in the 1870’s-80’s, jewelers begin to pick them up around 1930 or so; dentists figure out centrifugal casting in the 1920’s, jewelers pick it up in the late 1950’s and ’60’s. Our sense of tradition gets in the way of common sense working. I know of at least two trade schools in North America that insist on students using borax cones to make flux by grinding them on slates and according to what some students said not being informed at all about the existence of prepared commercial paste fluxes – which have been around a very long time.
Such egotistical and traditional education methods – endemic in the field in North America – really get in the way of a goldsmiths being successful and finding their working easy and rapid to do. Safety is like this too and it is time that goldsmiths addressed safety issues in their workshops out of sheer personal self interest. See the appendices for some safety sources.