Introduction to Silversmithing
Silversmithing is the art of shaping and manipulating silver into useful three-dimensional objects such as eating and drinking vessels, utensils, jewellery, armour and artistic items. As a traditional craft, it is said to date back to 4695 B.C. The oldest known items of silversmithed silver are ‘The Silver Scrolls’ that date back to 600 B.C. The scrolls consist of two small sheets of silver rolled into scrolls, upon which are inscribed the Priestly Benediction, found in a burial cave in Jerusalem.
Many of the tools used in ancient times are still used today, including tongs, anvils, and mallets. During the Middle Ages, the distinction between silversmith and goldsmith occurred, as silver was plentiful and cheaper than gold. Thus the goldsmith became more highly revered and was often the banker in the community. Traditionally, a silversmith will also work with other metals such as copper, bronze and brass, whereas the goldsmith prefers only to work with gold.
Pure silver [Ag] Melting Point 1761 F
Sterling Silver [.925] Melting Point 1640 F [893 C]
Sterling Silver is the most common alloy used in jewellery making and silversmithing. It was
adopted as a standard alloy in England in the 12th Century. Coin silver, once used in currency, contains more copper [10-20%] than sterling; it melts at a lower temperature and is more likely to tarnish.
RING MAKING: STEP–BY–STEP MEASURING
1. Cut a thin strip of paper.
2. Make the strip the same width as the wire, for most accurate fit. Wrap the strip around your finger.
3. Mark with a pen the point where the two ends of paper meet up to make a full circle on your finger.
4. Cut the strip where you have marked with a pen.
5. Wrap the cut strip around your finger again, making sure that the ends meet up to create a full circle.
6. Lay the strip out flat and measure length in millimetres with a ruler.
7. Use this length to measure your strip of silver wire. Use a scribe to mark the length onto your wire.
8. Cut with saw.
Conversion Chart: https://contenti.com/resources/ring-sizing-chart
When done properly, sawing is a relaxed, rhythmic experience without causing strain on the muscles.
Hold the piece of metal flat and steady against the benchpin. Always make sure that your fingers are not in the path of the sawblade!
Make sure that the saw blade is tightly strung in the sawframe.
The teeth of the sawblade must face outward and point downward toward the handle.
Saw with the blade at a right angle to the workpiece.
Keep the hand that holds the sawframe relaxed.
All files cut on the push stroke, away from the handle. Files cut in proportion to the force behind them. Place your index finger on the top face of the file to improve control and increase leverage.
Ends of wire that are to be soldered together need to be filed flat, for a tight seam. Bend the wire into a loop so that the ends meet, then file both ends at the same time, using a small flat needle file. Tension-snap ends closed, ready for soldering.
At soldering temperatures, the crystals of metal move apart, opening up microscopic spaces. The basic principle of soldering is to introduce an alloy that is fluid exactly at the point of maximum expansion. This alloy, known as solder, flows into the spaces to create an inter- crystalline bond.
RULES FOR SOLDERING:
The pieces must make a tight fit.
The joint and solder must be clean: no grease, pickle, buffing compound etc
Use boric acid solution to protect metal from oxidation. Each reheating usually requires refluxing. Use flux on the joints.
All the pieces being soldered should reach soldering temperature simultaneously. Heat the adjacent areas to reduce the flow of heat away from the joint. Take into account heat sinks such as binding wire, steel mesh and locking tweezers.
Where possible, position the torch so as to draw solder through a joint. Generally avoid directing flame onto the solder.
Use just enough solder to fill the joint [don’t use too much!]
Metal temperatures are judged by colour changes which can be seen best in a dimly lit area. Whatever your lighting, keep it consistent.
COMMON SOLDERING PROBLEMS
Incomplete or unsoldered joint – can be caused by insufficient heat, dirty metal, absence of lux or prolonged heating. Solution – Avoid playing the flame directly onto solder, make sure item is clean [pickle] and fluxed.
Solder balls up – Meral or solder may be dirty. Solution – Pickle and reflux, and try again.
Solder jumps to one side of joint. This indicates that one side is hotter than the other. Solution: Keep the torch moving so that all parts heat equally.
Solder spills out into a large puddle. Too much solder, too high a heat. Solution: Use smaller pieces of solder; level the heat as you approach the flow temperature.
Flux works by forming a coating that protects metal from oxidation. When heated, the fluid evaporates leaving a clear glassy coating that is more attractive to oxygen than the metal being soldered.
Firescale is a deposit of cupric oxide that grows within the structure of some copper alloys such as sterling silver and low carat gold. When copper-bearing alloys are heated in the presence of oxygen, oxides are quickly formed. Cuprous oxide [CuO] is a black surface layer that can usually be dissolved in pickle. Cupric Oxide [Cu2O] is a purplish compound that forms simultaneously within the metal. This is firescale. It must be removed with vigorous and thorough sanding, prior to polishing, otherwise when you polish your piece you will have areas that are different colour.
Boric acid + methylated spirits: classic formula to protect against firescale. To make the solution, add boric acid to methylated spirits until it stops dissolving [i.e. make a saturated solution]. The resulting thin paste will need to be shaken up or stirred periodically. To use it, dip the piece into the solution, set it on a soldering block and ignite it. The alcohol will quickly burn off, leaving a white film of borax. Many jewellers paint a little Handy Flux on the joint in conjunction with this, for soldering. This is a highly flammable solution, so for safety keep only a small jar on the soldering bench. Handy Flux becomes clear and fluid at 1100F [600 C] and is effective up to 1600F [870C]
Pickle is a chemical bath used to dissolve surface oxidisation and flux residue from the surface of a metal. Pickle works at room temperature, but the process is quickened with heat. You can find crock pots at second hand shops, these work well as pickle pots, set on low. SAFETY: When mixing, always add acid to water, never the other way around. Never use your fingers to pick up metals out of the pickle bath, as the acid can burn your skin. Use copper tongs to retrieve items from the pickle bath, as steel will cause a reaction that will discolour your metal and spoil the pickle. Pickle will last for some time, but as it absorbs oxides like a sponge, it will eventually reach a point where it has absorbed all it can carry. When it takes more than a couple of minutes to dissolve oxides, it is time to replace the solution. Before discarding spent pickle, neutralise it by adding baking soda. The solution will froth up, so work over a sink or outdoors. When the bubbling reaction slows down, it is safe to flush the solution. I prefer to tip it onto the ground rather than directly into the water stream, for added filtration.
WORK-HARDENING & ANNEALING
A sheet of silver is made up of crystalline structure – when the metal is worked the larger crystals are broken into smaller ones, which creates more grain boundaries. This is referred to as ‘work hardened’. Cooling metal rapidly will achieve a similar effect. Because the crystals do not have time to grow into an organised structure, the metal recrystallises into many small grains. The increase in grain boundaries increases the surface tension, i.e. hardness of the metal surface. If you continue to work past the point of work-hardened state, the metal will split or crack under the stress. This is why we anneal the metal in order to be able to continue to work it.
When we heat the metal to a prescribed temperature with a torch or kiln, the crystalline structure begins to relax and loosen. This process is known as annealing. After heating the metal, quench the piece in water to cool, then dip it into pickle to dissolve surface oxides. In its annealed state, the crystal arrangement contains irregularities that contribute to the malleability of the metal. For most jewellery metals, heat the metal to a dull red colour and quench as soon as the redness fades.
A polished appearance is the result of a perfectly flat surface. A flat surface bounces all the light back, which we see as a bright shine. After removing any irregularities with a file, work through the grades of sandpaper from coarse to fine. Sandpaper grades: 100 very coarse, 200 coarse, 300 medium, 400 fine, 600 very fine... and so on to 1500 which is ultra-ultra fine, to almost polishing level.
BUFFING / POLISHING
Can be done using a flexshaft machine with a variety of specific attachments, or a buffing machine, using large mops or wheels impregnated with various polishing compounds. SAFETY: When using the buffing machine, pay attention! Always work only on the lower quarter of the wheel. Keep hair back. Don’t wear loose items of clothing such as scarves that could get caught in the wheel.
STARTING YOUR OWN WORKSHOP
Here is a list of basic tools and equipment you will need, should you decide to set up a studio at home. There are many specialised tools that can be added to your studio over time. Where possible, it is recommended that you buy the best quality tools you can afford. Cheaper tools are made from inferior materials and will not last, and the pleasure of working with quality tools greatly enhances your experience.
PLIERS – for forming, holding
SNIPS – cutting solder & thin wire
SAW FRAME & SAW BLADES – blades come in different thicknesses. If the blade is too small for the metal being cut, it is more likely to break. If the blade is too large, it will cut with a jerky motion. Sawblade guidelines: 22 – 24ga: 3/0 or similar; 16 – 20 ga: 1/0 or similar, 10 – 18 ga: 1 or similar.
HAMMERS – The heart of the metalsmith’s tool kit. Many different kinds available – basic starting hammers include chasing, riveting, ball peen, forging and planishing.
MALLETS – traditionally made from treated rawhide, but also available with nylon, plastic or rubber heads. Used for forming metal without stretching or marring.
BENCH PIN – Best made from hardwood. Used for sawing and filing.
FILES – Large flat file for general use; assorted needle files for delicate shaping, cleaning up solder etc.
SANDPAPER – Work through the grades from 600grit to 1500grit to get a nice, flat surface for polishing. Sandpaper can be taped to dowels and flat sticks to increase leverage when sanding.
TWEEZERS – for picking up solder, small components etc
TORCH – A basic hand held 0.34kg LPG gas bottle is sufficient to begin with. You will need to purchase different nozzles for the flame - get the finest one available for fine soldering work, and a mid-sized one for annealing larger pieces.
CERAMIC SOLDERING BLOCK – to create a soldering station.
THIRD HAND – holds items in place when soldering.
MANDRELS, ANVILS & BENCH BLOCKS– Steel pieces used to form metal. There are different sized mandrels for making jump rings, rings and bangles. You will need a basic steel bench block.
PALLOYS - Metal fabricators. https://www.palloys.com/
AJS – Australian Jewellers Supplies. Tools and Equipment. http://jewellerssupplies.com.au/
RIO GRANDE [US} - Tools and Equipment http://www.riogrande.com
OTTOFREI [US] - http://www.ottofrei.com