The Making of the Kedleston Tumbler Cup

Blocking/ Sinking

Starting with a flat disc of silver, I use a ball peen hammer to hammer from the inside, into a wooden concave depression. The metal is hammered from the edge towards the centre. This technique stretches and thins the metal to form a shallow bowl shape.

Hand raising

The next stage is to form and compress the shallow bowl shape with a raising hammer over a steel stake. This is performed in a concentric pattern to produce a hollow three dimensional form.

At each stage of the raising operation, the cross section of the stake and the type of hammer are varied and must be carefully selected according to the desired contours of the finished article. Its then down to a bit of luck and hitting the hammer in the right places!

Bouging

Bouging is usually done with a wooden, horn or leather mallet to smooth the worked metal after it has been raised.

Caulking

Caulking is an operation performed to thicken the edge of a vessel being raised. It is usually done after each raising course and before each annealing. Overlapping hammer blows are delivered directly against the edge, at a right angle to the face of a cross peen hammer, while the work piece is held on a sandbag.

Metal is ready for annealing when it has become work hardened and does not move in reaction to the hammer blows. An indication of this condition is the change in the sound of the hammering which is dull when the metal is in a working condition, and high pitched when it needs annealing.

Annealing

Annealing is the action of heating metal to a dull cherry red to restore the malleability to the metal after it has been work hardened through repeated blows of the hammer. The process of frequent annealing prevents metal from cracking while it is worked. When annealing a large soft, neutral flame is used. The annealed metal is held with brass tongs and submerged in a water bath this is called quenching. The metal is then placed into an acid pickling bath.

Pickling

Pickling cleans and removes oxides from the surface of a metal, which form during the heating process.

After it has been pickled, the metal is left a matte white colour. This helps in the next cycle of hand raising in seeing the new set of hammer footprints on the surface.

After the piece is finally shaped, the entire surface can be refined by planishing with a light, half pound planishing hammer, which has a highly polished, slightly convex face, over a responding stake.

The result is a very smooth inside and a controllable series of facets on the outside. This characteristic texture to the surface is often used as a decorative element. The silversmith must use great care when using this process as even a tiny speck of dust will leave an impression on the surface of the silver.

Chasing

Chasing adds decorative detail to metal with the aid of steel punches and a chasing hammer.

The design is scribed on the surface of the object. The object is then filled with pitch, which is a material that provides a firm working surface that is resilient but with enough elasticity to allow the silver to be impressed by the chasing punches.

The pitch can be melted and removed once the chasing has been completed.

A light chasing hammer, known for its large, flat face and oval shaped handle is used with punches to produce a decorative effect by pushing the silver into relief. Pitch is essentially composed of a sticky elastic substance (pine pitch), plaster (which changes the degree of stiffness), and oil/ tallow is added to soften the pitch.