Wednesday, August 24, 2011

The Shadow Knows...

Let's have a chat about purple shadow... not purple haze, not purple rain... purple shadow, otherwise known as fire scale: the bane of every silversmith's existence.

Sterling silver is an alloy of copper and fine silver in the proportion of 925 parts silver, 75 parts copper. But don't be fooled by that tiny bit of copper, it is a trouble maker. Copper is the reason that sterling silver tarnishes. Fine silver (999 parts silver) is much more tarnish resistant.

As you work with the silver (file it, hammer it, sand it, form it) the alloy is getting moved around, compressed... and this compression brings the copper to the surface of the silver. As the alloy undergoes this compression, "islands" of raised copper start forming and create portions in the surface of the metal that tarnish faster than the surrounding metal... and these "islands" manifest as purple shadows on the surface of the silver.

There are two ways to get rid of fire scale. 1. continue filing/sanding until the island of copper is gone. 2. go through several rounds of heat/pickle (heating the metal to bring out the oxidation then throwing the hot metal into acid so that the oxidation is eaten away), a process known as "raising the fine silver." I prefer method 2 because I find method 1 risky... I never know how deep the fire scale goes, and I could very well file through the whole piece before the fire scale is gone.

It's the mark of a well made silver piece to have no fire scale... it's a time consuming process to get rid of purple shadow and it is definitely a labor of love. So, the shadow definitely knows how much time was put into the jewelry you wear.

Wednesday, August 17, 2011

What the Flux?

In jewelry, "flux" is a weird term because it can mean many things based on context.

When soldering, "flux" is a paste or liquid that keeps the metal clean during the soldering process. Soldering requires that you heat metal to extreme temperatures; however, the heat causes the metal to oxidize. This type of "flux" is a chemical compound (containing fluorides, potassium, and hydroxide) that creates a barrier between the metal and the air, stopping the oxidation and helping the solder flow. And since solder will not flow over dirty metal, flux is essential for getting a nice, tight solder seam.

The next two types of "flux" apply when you are talking about enameling with powdered glass. The first type is simply clear enamel, meaning that in this case, "flux" is just clear glass. The second type of enameling flux is similar to soldering flux in that it is a chemical compound. In enameling, this compound is mainly xanthum gum; you cut it with water and use it as a binding agent between the powered glass and the metal. In this context, you use "flux" to keep the powered glass where it belongs so that it will stay in place to be kiln fused and torch fired.

Consider yourself educated! Now when you're at a fancy dinner party or hip, trendy spot and someone says, "What the flux?" you can whip out your knowledge and impress them all.

Monday, August 15, 2011

Current Theme Song

"Awake My Soul" by Mumford & Sons on Sign No More

In these bodies, we will live
In these bodies, we will die
And where you invest your love
You invest your life