SILVERSMITH'S WORKSHOP

Introduction

To fully appreciate the quality and value of old Burmese silver requires an understanding of how the silver was crafted and decorated by the silversmiths. This Magazine article is an introduction to the forging methods, tools and decorative techniques used to craft the silver displayed on the Noble Silver website. It’s also intended to ‘translate’ and explain the technical jargon of the silversmith’s craft.

Many of the photos used to illustrate the techniques and tools are from ‘modern’, active workshops in the villages of Ywa Htaung in Sagaing and Ywa Ma on Inle Lake in Shan State. These are simple, spartan and austere workshops. The few extant photographs from the workshops of a hundred years ago suggest that the silversmith’s ‘hardware’ has changed little over time. On the other hand, and regrettably, the ‘software’ skills and professionalism of modern silversmiths have declined precipitously since the Burmese ‘Silver Age’ in the late 19th and early 20th centuries.

Silver and Silver Alloys

Silver has specific properties that make it an almost ideal metal for working into objects of fine art. These properties determine the methods and tools used in the silversmith’s workshop. Silver is malleable and ductile. These two properties permit cold-working of the metal at room temperature. And, silver’s relatively low melting temperature of 960 C is quickly achieved in a simple charcoal furnace using a hand operated air pump. This allows the silversmith to easily anneal and melt silver as often as required.

Ancient silversmiths first worked with pure silver metal which is soft and easily cracks when overworked. To overcome these disadvantages, other metals were mixed with pure silver to produce silver alloys with optimum qualities for metal working. Copper is the most common metal alloyed with silver. Sterling silver, an international standard in the silver industry, contains 92.5% silver and 7.5% copper and/or other minor metals. Sterling silver increases the strength and hardness of pure silver and retains most of the cold-working advantages of the pure metal. In Asia, an alloy composed of 90-93% silver and the balance in zinc produces a silver alloy with a white colour and exceptional brightness.

Old Burmese silver was made from domestic and international silver ingots and bars, silver coins and recycled silver. The purity of silver bullion varied according to its source and ranged from under 90% to over 95% silver. The two principal silver coins melted to produce silver were the King Mindon peacock and the British Indian rupee. The peacock was minted from 1865 to 1885 in Mandalay during the reigns of King Mindon and King Thibaw. The Indian Rupee was a British colonial coin. The silver content of these two coins was about 91%.

The word ‘silver’ is commonly used to describe both pure silver metal and silver alloy.

A Brief History of Silversmithing

All Burmese silver made in the 19th and early 20th centuries was handcrafted in small artisanal workshops using traditional silversmith’s tools and techniques. The methods employed had changed little since silver was first forged and decorated more than three thousand years ago. The Sumerians, Phoenicians, Cypriots and Egyptians all worked silver by hand to produce exquisitely decorated silver. The art of repoussé is said to have been ‘invented’ by Polykleitos, a Greek sculptor from the period of classical antiquity in the 5th century BCE.

Fourth register wall paintings in the Rekhmire tomb at Thebes showing metal workers casting, forming, soldering, polishing and decorating gold and silver vessels for the use of the Gods – dated 1479-1425 BCE, New Kingdom Egyptian Era.

In the land area known today as Myanmar, the earliest known silver dates from the Pyu Period during the 3rd to 9th centuries CE. The Khin Ba mound, discovered within the walled Pyu city of Sri Ksetra in 1926-27, contained many hand crafted silver artifacts, including a magnificent funeral reliquary decorated with high-relief repoussé images of the Buddha and inscribed in both the Pali and Pyu languages.

The silver reliquary from the Khin Ba mound, Pyu Period, Sri Ksetra – central Myanmar

There are few surviving pieces of Burmese silver from a 1,000-year period of history that begins with the fall of the Pyu kings in the 9th century and ends in the Konbaung dynasty in the mid-19th century. The great ‘Silver Age’ that blossomed from the mid-19th to the early 20th century was the historical zenith of Burmese silver art. The prized, high-quality pieces from this time are now in collections around the word.

Techniques and Tools

Forging Techniques

Forging is the controlled shaping of silver using the force of a hammer.  The forging and decorative techniques illustrated below are used primarily to handcraft traditional Burmese silver bowls. Other styles of silver are made using variations of these basic techniques.

Silver source – Burmese 999 silver ingot and 1 Kyat silver peacock coin

Silver source – pellets from scrap metal

Melt components of a silver-copper alloy. Silver ingot metal, copper wire and plate and silver alloy scrap.

Casting a silver alloy disc from molten metal in a ceramic crucible.

The first step in making a silver bowl is to cast a silver disc with a diameter equal to twice the distance between the design centre of the bowl’s base and its upper rim. The body of the bowl is then raised by hammering the disc in concentric circles against a wooden anvil or stake. This process initially stretches out the middle of the silver disc to form a saucer shaped object. Further hammering of the inside of the saucer in downward and upward spirals raises the edges to their final height. Hand raising produces the highest quality bowl but is the most time consuming and expensive forging technique.

Stages in the forging and decoration of a traditional silver bowl.

From right to left – silver ore (acanthite), a silver metal bar, a cast silver disc, a saucer raised to the final diameter of the bowl, a fully raised bowl, a bowl filled with pitch to support exterior decoration and a completed bowl decorated using repoussé and chasing techniques.

Sinking is an alternative and quicker technique to produce a bowl, either to full height, or as a first step in raising the bowl. The technique is to forcefully hammer a silver disc into a hemispherical die in a block of wood. Hammering progresses from the circumference of the bowl to the middle. Stretching is another technique to create a bowl shape by hammering sheet metal against an anvil.

Spinning is a silver forging technique that dates from the Industrial Revolution and is primarily used for the mass production of silver. This fabrication technique was not used in traditional Burmese silver workshops. It is a mechanical method of metal working - a lathe ‘spins’ a silver disc against a wooden or steel ‘chuck’ shaped in the form of the desired object.

Hand raising the sides of a silver bowl using a raising hammer and a supporting wood block.

The silversmith must maintain the thickness and symmetry of the bowl – this requires skill, experience and time. Many weeks of patient and consistent hammering are required to raise a high-quality bowl.

Seaming is a starting technique used to produce large objects and to reduce the fabrication time. A flat sheet of silver is wrapped into a cylinder and the seam, or join, is soldered. The form is completed by soldering a flat disc to the base of the cylinder. Hand raising completes the final shape of the bowl. The quality of bowls made by the seaming process is typically inferior to hand raised bowls

A cylinder formed by ‘seaming’a flat sheet of silver.

The final bowl form created by adding a base disc to the cylinder and rasing the sides

Annealing

Hammering hardens metal in a process called work-hardening. For example, cold working fine silver increases its Vickers hardness from a factor of 26 to 95. The hammer blow on the silver dislocates crystal lattice boundaries and increases stress in the metal. Large silver crystals are broken into smaller crystals, the metal becomes less malleable and eventually the silver will fracture. Annealing is the process of reducing stress in the silver by heating it to about 650 C for less than a minute and then quenching it in cold water. The effect of this process is to restore the silver’s softness and malleability for further working.

Hand raising the sides of a silver bowl using a raising hammer and a supporting wood block.

Annealing a small bowl in a silversmith’s workshop

Heating the bowl to about 650 C

Quenching the bowl in cold water

Traditional hand operated bellows are used in Burmese silver workshops to blast air through a nozzle into the small charcoal furnaces used for annealing. The oxygen in the air accelerates the combustion of the charcoal and quickly increases the furnace temperature to about 650 C. The design and operation of the bellows have not unchanged in centuries.

A two-tube bamboo bellows

The plunger made from downward facing cockerel feathers

A hand operated bellows using a flexible leather air bag between two rigid boards

Die Forming

Die forming was used for repeated designs and matching small parts like a lime box and its lid. In this process, annealed silver is pressed, or forced, against a pre-formed bronze or steel die shaped to the crude design of the piece. This is a type of embossing.

A bronze die for the lid of a lime box featuring three adults and a baby sitting on a throne. This design was common on Burmese lime boxes and is believed to symbolize respect for the royal family.

Casting

Silversmith’s use the casting technique to create three-dimensional, solid silver objects, either as standalone pieces or adornments to be soldered to a larger object. The finials soldered to the top of ornate betel boxes are made by casting.

To create a cast object, molten silver is poured into a mold of the desired shape. The mold is traditionally made using the ‘lost wax process’.

Casting – molten silver is poured into a clay mold of an elephant head

The detailed elephant head after removal from the mold

Pickle and Firescale

The heating of copper bearing silver alloys during the annealing process inexorably leads to the oxidation of the copper and the formation of cuprous oxide (CuO) as a black surface layer. Pickling is a room-temperature process that dissolves the black layer from the silver object. The pickling solution absorbs the copper oxides and eventually becomes blue in colour when saturated. A typical pickle solution for sterling silver comprises one part sulphuric acid and ten parts water. silver is pickled after the quenching stage of the annealing process.

Firescale is a deposit of purplish cupric oxide (Cu2O) that grows within the silver-copper alloy during heating. The only method of preventing firescale is to heat the metal in an oxygen free environment, although this isn’t feasible in a traditional silversmith’s workshop. Firescale can be removed by dipping the silver object in a bath of strong nitric acid.

Pickling baths – the blue solution inside the basin in the foreground contains copper saturated solution.

Silver Solder

Soldering is a skilled process for joining together two pieces of silver. The solder, comprising an alloy of silver, copper and zinc, diffuses into the surface of the solid metal it touches and creates a strong bond when the metal cools. The melting point of silver solder is primarily determined by its zinc content. A 4% zinc solder melts at 809 C and a 15% zinc solder melts at 681 C. It is important to use progressively lower temperature solders when over-soldering, otherwise the earlier solder will dissolve.

Filigree

This technique is used to create highly decorative and delicate forms by soldering together fine silver wire.

Silversmith’s Tools

Old Burmese silver was hand crafted by silversmith’s working in small workshops with simple, traditional tools. The photographs below illustrate common tools used in a typical, village workshop to produce small silver bowls and boxes.

 

A wood stump with depressions for sinking, raising hammers and a steel planishing iron.

Steel stakes set in wood blocks for forming shapes in silver.

Planishing and raising hammers

Hammers – the most important silversmith’s tool. On the rack - planishing, repoussé, chasing, ball-peen and raising hammers.

Hammers, steaks, protractor, punches, liners and gravers.

The hand tools for repoussé and chasing work.

Shaping and Decorating Silver

The most common tools used to shape, form and decorate silver objects are made from round, square and hexagonal carbon-steel rods. A steel with about a 1% carbon content is sufficient to work silver and most silver alloys. Individual silversmiths customized their own tools to create the most effective and comfortable to use instruments.

Repoussé and Chasing

Repoussé and chasing are the oldest and most versatile techniques for working, shaping and decorating silver. The magnificent decoration on old Burmese silver featuring high relief images from the Buddhist jatakas, or the Ramayana epic, is all due to the exceptional repoussé and chasing skills of the master silversmiths.

‘Repoussé’ is a French verb meaning “to push back”. The silversmith’s meaning is to push metal to create volume with no loss of the original metal. In practice, repoussé work is done on both the inside and outside of the silver object. Chasing refers to the incision of lines, patterns, crisp edges and designs on the front, or outside, of silver objects without metal loss. Repoussé and chasing are often used together to produce elaborate decoration and the two terms are used loosely to describe different styles of decoration. In practice, repoussé and chasing refer to a family of techniques used to form silver.

Silver objects need to be supported during the repoussé and chasing work to prevent any sinking of the metal in the area surrounding the impact point of the steel tools. The support medium needs to be elastic, able to adhere quickly to the metal and be easily released from the metal when the work is finished. The most common support used in Burma is black pitch, a mix of asphaltum, brick dust or plaster, and tallow. Yellow pine resin is also used as a substitute for asphaltum.

Decorating the outside of an offering bowl using the repoussé technique.

Black pitch between a cylinder and a large silver bowl

Black pitch and a handle for control

Chasing work Edge sharpening and detailed lining.

Chasing work. Lining a box edge.

Repoussé Tools

Steel repoussé tools are customized by the silversmith in a wide variety of shapes and sizes. Punches are used to push out metal from either the front or the back. The tools have rounded faces or softened edges. Dapping punches can also be used for repoussé work.

Chasing Tools

Straight Liners

Straight liners are used like an artist’s pencil to outline the design on the silver object before starting the repoussé and chasing work. They are also used to create decorative patterns and textures. Tracers are similar tools used for marking lines.

Running Punches

These punches are like liners and are used to create rounded indentations.

Matting Tools and Stamps

Matting tools and stamps create a specific pattern on the metal. They can be used to create subtle background textures and sharp marks on silver metal.

Undercutting Tools

An undercutting tool pushes down background metal to create exceptionally high relief forms that can appear to be almost three dimensional. This technique is used extensively to produce high relief animal and human figurines on Burmese silver. Undercutting also separates and detaches design elements which then creates a sense of depth to the surface decoration.

Planishing Tools

Planishing is a technique for smoothing and polishing metal with a specialized hammer. The hammer head is highly polished to a mirror finish. A planishing iron is used to polish the inside of formed silver objects. Planishing is one of the last work processes because it hardens the silver.

Engravers

Gravers are hardened steel tools used to cut lines in silver. The lines are cut out of the metal and not scored.

Piercing

Piercing, perforation or open-work, refers to the technique used to create open-spaces on the surface of a silver object. The shaped open-space is created using a combination of a drill, saw, punch and a file. Piercing may remove over 50% of the silver on a decorative face or side. Skilled silversmiths use piercing to create forms and images in the latent silver lattice.

Burnishing

Burnishing is a traditional finishing technique to smooth and polish the flat surface of a silver object. The tools are often handmade and rubbed with pressure against the metal to create an even shine.

Pricking

Pin-pricking is used to inscribe letters, figures and symbols on silver metal. Maker’s marks, ownership names and other text is occasionally pricked on the underside of the base of Burmese bowls.

Niello

Niello refers to a powder mixture of copper, lead, silver and sulphur used to create a black, reflective inlay effect on a silver object. The powder is mixed by hand, placed within a design ‘frame’ on the silver object and heated to about 370 C to fuse the niello into the workpiece frame. The niello surface is then burnished to create a soft, bright appearance like hematite. The word niello derives from the Latin nigellum meaning ‘blackish’. The black colour is due to the high sulphur content of the niello.

Niello powder is made by melting the constituent metals together and adding as much sulphur as the melt can absorb. This process creates large amounts of poisonous sulphur smoke and requires high heat. Old silversmith workshops rarely provided adequate ventilation or cooling and therefore the niello technique was not favoured and good quality niello silver is rare.

A small niello bowl decorated with a finely detailed floral design.

Gilding

Gold leaf gilding was a technique rarely used by Burmese silversmiths in the late 19th and early 20th centuries. The very thin gold sheets, often with a 22K or 24K fineness, are pressed onto a clean, and often varnished, silver metal surface. The gold adheres quickly to the silver and multiple layers can be applied to increase the depth of gilding.

A Silversmith’s Check-List for Hand Crafting a Silver Bowl

The handcrafting of a silver bowl is a complex, multi-stage process requiring both technical and artistic skills. The many stages are summarized below;

  1. Cast a silver alloy starter disc containing about 92.5% silver.
  2. Work the disc into a saucer shape by sinking or raising.
  3. Hand raise the saucer to the final size and shape of the bowl.
  4. Frequently anneal the silver to preserve malleability.
  5. Pickle the metal after annealing to remove copper oxides.
  6. Use a pencil and liner to sketch the design outline onto the bowl.
  7. Push out the design from inside the bowl using repoussé techniques.
  8. Fill the bowl with pitch and use chasing and repoussé to form all the decorative elements on the outside of the bowl.
  9. Repeat steps 7 and 8 as required to complete the decoration.
  10. Anneal the bowl after each step of the chasing and repoussé work.
  11. Planish and burnish the undecorated silver metal.
  12. Pickle and dip the bowl in nitric acid to remove all copper oxidation.
  13. Wash in a boiling alum bath to clean the bowl.
  14. Scrub and wash with soap fruit followed by a final cloth or ceramic bead polish.

The time required to complete a silver bowl is determined by the size of the bowl and the proportion and detail of the decoration. A large bowl with a diameter over 25 cm and detailed decoration might require up to a year or more to complete. In a family or larger workshop, there would be a division of labour based on skill and experience. Apprentices or junior silversmiths would perform the less-skilled work whilst the master silversmith was responsible for design and decoration using repoussé and chasing. The results were works of fine art.