How to Solder Gold

In soldering gold, the basics you will need are: gold solder and soldering flux. Recommended also, is a precision torch such as the Little Torch.

1. All parts must fit very well together, and be absolutely chemically clean and grease free. Soak all parts in acid (pickle)to remove oxides, neutralize with baking soda and water and scrub with Formula 409 or Dawn dish washing liquid. Parts won't solder if they are dirty or oxidized. Flux won't flow into a joint if the parts are greasy and repel water.
2. Apply a small amount of flux to the parts being soldered together.
3. Heat slightly, just enough to 'cook' the flux (or it will 'cook' as you're trying to apply solder and the solder will pop off). What we are doing in this step is boiling off the water in the flux, leaving behind a crystallized film of borax and other chemicals, which fuse into a syrupy flux glass, inhibiting the formation of copper oxides which impede the flow of solder.
4. When soldering gold, you want to apply the heat directly to the area being soldered, as opposed to soldering silver where you should heat the entire item. The reason why is that gold is a slower conductor of heat than silver or copper. Silver (the fastest conductor of heat and electricity, then copper) quickly radiates heat away from the point nearest the torch. One must heat the entire piece to the soldering flow point.
5. When the flux has boiled dry, apply a small amount of solder and heat directly onto the solder, moving your flame back and forth slowly so as not to create a hot spot.
6. When the solder and item reach the right temperature, the solder will flow across the two sides being soldered. Let it cool. Remove the excess flux in pickle or boiling water and polish.

• You can buy gold solder in sheet form, wire form and, from some dealers, in 1 mm chips (the advantage of the chips is that it's easier to control the precise amount of solder being applied). Gold solder comes in easy, medium and hard, which denotes its melting temperature (easy melts at a lower temperature), but isn't as hard as 14K gold.

• Gold Soldering is not something for the novice. You can easily destroy whatever it is you are trying to solder.