Korean for the term "attached gold," Keum-boo, sometimes spelt as kum-boo, is an ancient Korean technique. This technique allows thin 24ct gold to be bonded to silver and permanently fused together. This technique is used in much of our pressed flower jewellery.
There are variations to this technique commonly seen in Japanese and Chinese metalwork. It can also be used when referring to attaching gold to steel, iron and copper. This technique has been observed for as long as the second half of the first millennium one. Sometimes, the old fashioned ways are the best!
Mixed Metal Jewellery
Keum-boo is made possible because pure precious metals, including silver and gold, have quite similar atomic structures making it easier to properly fuse them together. Heating these metals together increases the movement of these atoms. When hot enough and pressure is applied with a stone burnisher, the metals will fuse together. So cool! This all occurs below the soldering temperature for both metals.
This technique is done by bringing to the top a thin layer of pure silver on the sterling silver jewellery piece. This is depletion guiding. 24 Carat gold is then placed on the silver and using pressure and heat, a permanent bond is created.
Every artist works in a slightly different way. These are tools that needed to complete the process of keum-boo, and these include gold, wooden chopsticks or a wood stove thermometer, clean tweezers, thick tracing paper, small sharp scissors, a heat source, baking soda, a small container and burnishers either made from agate or steel.
It also requires a proper workplace to ensure that nothing gets in the way of the process. The space must be wiped clean and dry and a smooth surface that is heatproof must be prepared. Usually, this means working on surfaces made of ceramic, glass or steel. Having a fire blanket or a fire extinguisher nearby if you are working around paper is encouraged!
The ancient technique appeals to me very much and I use it often in my English garden workshop creating flower jewellery. I begin by annealing the sterling silver piece a total of seven times, heating it until it becomes a salmon pink colour. It is then quenched in water. This process is repeated at least 7 times, bringing the pure silver layer to the surface. Now it is possible to fuse 24-carat gold to the silver.
For each piece of floral jewellery the 24ct gold is added by hand, making each piece truly one of a kind and memorable. That is what makes the pieces so special! Your own little piece of wearable art! See the finely textured details in each piece of jewellery in our Pressed Flower Jewellery range.
24ct Gold and Sterling Silver Jewellery
If you'd like to learn more about this process of adding 24ct gold to silver jewellery, take a look at our video.