Tuesday, September 10, 2013

Soldering Overview and Tutorial Preview

I've been working on a blog post tutorial for this pair of soldered and wirework earrings.

Etched, Soldered, and Wirework Earring

As I wrote it I realized that I wanted to have a video to demonstrate how to solder the cabochon bezel cup in the design and didn't want to delve too deeply into all the technical aspects in the video. But, to do soldering successfully, it's important information to understand - particularly for the delicate soldering used for the earrings. So, in preparation for that tutorial, I'm going to start breaking it down. Today I'm going to talk about what's going on at a molecular level. Tomorrow we'll talk more about flux.

For the non-jewelry makers that have made it this far - stick around. I know this may not be information you'll ever use, but if you think you're ever going to purchase artisan jewelry that's been soldered, it may be helpful to you to know this so you can ask questions of the artist and better judge the quality of the product before you buy.

soldering: molecules

Soldering is possible because metals are made of molecules in a crystal structure, allowing the molecules of a lower-temperature solder to flow within the molecular structure of the piece you want to join. This is called an interstitial bond. I work primarily with sterling silver, which is 92.5% silver and 7.5% copper.

soldering: interstitial bonding

The sterling's copper molecules hate being alone and, if you don't use flux, they can bond with oxygen molecules from the air at temperatures lower than the melting point of solder. This creates what is known as firescale.

soldering: troublesome oxygen

soldering: oxygen bonds

Once the copper binds to the oxygen little to no room for the solder molecules. Even if a bond is formed, it is going to be weak. So, allowing a strong bond to be formed at the joint is flux's most important role, but it is also used to prevent firescale from developing on the rest of the piece that's being soldered. More about that tomorrow!

Thanks for stopping by!


  1. As a beader who's just venturing into soldering, you had me at interstitial bond. Fabulous post - I'm hooked! (And I so want to know how to make that wee bezel cup!)

    1. Thanks, Karin! Wee bezel cups aren't too difficult to make (just putzy), so I'll admit that I usually just buy them premade from Thunderbird Supply since they also sell the 3 and 4mm cabs I like to use for embellishment.