Thursday, February 02, 2012

Hallmarks and Purity Marks for Metal Clay Jewelry

I have a fetish for the backs of my work. I want the reverse side to have as much care and planning as the front, so I often embellish it. Even adding hallmarks and purity marks should be done with a degree of finesse.

Because all my recent work is sterling, I want to mark it with .925 (sterling is 925/1000 silver). I could just stamp it during the process, but that runs the risk of marring the front side. My solution is to stamp into a thin sheet of fresh clay, then cut out tiny decals to adhere. I use the same process for my hallmark. (In case you're wondering, my name is for real -- I was born with it!)

Here's my process:
  1. roll a sheet of clay one card thick
  2. gently mark with a commercial steel .925 (or .999) stamp or hallmark
  3. use a cutter (a straw or tube) to cut out a circle around the mark, or use a knife to cut straight sides
  4. dry and refine if needed
  5. to attach, simply moisten both greenware surfaces with a damp brush and press firmly together
  6. add a light wash of water with the brush around all the edges and then dry
  7. fire piece as usual

Voila! Professional markings in little time. Hint: I make a bunch of each mark at a time, then store the dry decals in a container to be ready when I need them.

Here are the latest sterling clay earrings, from the front: