Robin Phillips Jewelry

Keum Boo (also spelled kum-bu) is a Korean process whereby 22k gold foil is permanently bonded to silver, giving the appearance of the two metals being one.

First, the object is made in sterling silver and then depletion plated to bring up a layer of fine silver to the surface. This is done by repeatedly heating and then quenching the metal in acid. This process is repeated 4-5 times.

Very thin 22k gold foil is placed on the depleted silver while gently applying heat with an open flame. The piece is then placed on a steel block and, using a polished steel burnisher, the gold is pressed down over the surface - fixing it permanently in place. The gold will not bond unless the surface is fine silver and the correct temperature has been reached.

Any future soldering can affect the keum-boo so care must be taken not to over heat the piece. After completing the process the piece may be textured by putting it through a rolling mill or using a scratchbrush. The finish is permanent.

Married metal is a term used to describe the process of soldering different metals together using high temperature solder. I usually use a combination of silver, gilding metal, nickel silver and copper, although other metals can be used.

After soldering the pieces together, they can be cut and re-soldered thereby altering the pattern that had been initially formed. This can be done again and again, making the pattern quite intricate. When happy with the pattern, the piece must be filed back to clean away all the excess solder (and there is a lot of this!) to reveal the subtle pattern beneath.

The finished piece can be coloured by introducing an open flame which will intensify the colour of the metals, or it can be left to oxidise naturally. Sometimes I use a sealant to keep the colour permanent. I usually set the piece as I would a stone because to solder it again I run the risk of the joins opening and the piece buckling.

This is similar to the 'married metal' method. A design is saw-pierced from one metal and inlayed into an exactly matching opening in a different metal.

They are soldered together with high temperature solder. As with married metal, the piece must be filed back until dead flat and all solder removed.

It can be coloured with an open flame or left to oxidise naturally. It can also be sealed to preserve the colour.

This type of forging (called anticlastic raising) persuades the metal into opposing itself. Concave curves and tight tapering enclosed curves are made possible with this technique. Bangles, rings and neckpieces as well as hollow 'tubular' handles are born of this method.