Most jewelry is made with not just one metal, but 2 or more melted together in specific proportions to form an alloy. By adding metals like copper, palladium, zinc, and the like, jewelers (and their refiners) have learned to create a rainbow of metal alloys with a wide variety of strengths, working characteristics, melting points, etc.
For instance, sterling silver is the standard metal for silver jewelry. It is an alloy of elemental copper and silver - 92.5% silver and 7.5% copper. The copper increases the strength of the silver, making it stronger and more durable.
Gold is similar in that it is rarely used in its elemental form - pure gold is quite soft and malleable. Remember those TV shows with pirates or cowboys biting down on the gold coin to see if it is real? Pure gold you really can leave a mark in with your teeth.
The most common alloy of gold is 18k yellow gold. The 'k' stands for karat, and tells us the percentage of gold in the alloy. 24 karat = pure gold. 18 karat is 18 parts of 24, so divide 18 by 24 = 75% gold. So, 18k gold is 75% pure gold. What's the rest of it, you ask? To keep the color yellow, usually equal parts copper and silver make up the other 25%.
Is gold always yellow? Technically .... yes! Pure gold is always yellow; other colors of gold are actually gold alloys - created by using different metals in the non-gold part of the alloy. For instance, 14k rose (or red) gold is a common alloy - it contains 58.3% gold (14/24 for you mathy types), with the balance (41.7%) mostly copper. That's why rose gold is coppery colored! It is still a stable, precious, non-reactive metal though, because of the stabilizing properties of the gold. Any gold alloy containing 50% or more gold will be stable and non-reactive, suitable for jewelry and use in mokume gane.
The real question - what is palladium white gold?? This entire post is actually a lead up to answer a question I get all the time - what is palladium white gold?? Is it palladium, or is it gold? By now, you can probably guess it is an alloy of both. I use 14k palladium white gold all the time in my mokume gane because I love its dark gray color and its strength. It is 14k, so we know it has to be 58.3% gold. The balance is mostly palladium, a dark gray precious metal used in jewelry but also in catalytic converters.
Bonus question - Is all white gold made with palladium? No! It is much cheaper to make white gold with nickel, a light gray inexpensive base metal. However nickel white gold is banned in many countries because up to 25% of the population is allergic to it. This (and the color) is why most nickel white gold jewelry is rhodium plated. It's more expensive, but for many reasons palladium white gold is the right choice for mokume gane.
So, with all that information, look at the photo of the billet on this post, and see the 3 colors in a new light - you are looking at 14k palladium white gold (gray), 14k rose gold (red/rose) and sterling silver (white). Does anyone want to guess what percentage of gold the billet contains? (by volume, not by weight - that's another blog post). Hint: half the billet is 14k gold of one color or another. Give it your best guess in the comments below. First two correct answers get a $40 gift certificate good on classes or jewelry!
Update: thanks to those who played! The correct answer was 29.15% . The billet is 50% 14k gold. 14k gold is 58.3% gold, so, 50% of 58.3% = 29.15%
Congratulations to the first two correct answers - Chris L. and Ben B. I'll be emailing your $40 gift certificates. Yay!
Spring was a fun semester, full of fold-forming , stone-setting and box-making. Lots of creativity here; especially Juan's fold-form fish and Yoko's hairpin!
Uchidashi (loosely translated "hammering down") is a Japanese metalworking technique for creating small 3-dimensional shapes from sheet metal. The technique has been compared to chasing/repousse because of the similarity of the tools used, but really it is quite different. I just returned from England, where I studied this technique with Ford Hallam, a top expert in Japanese metalworking. Here is a visual walk through of my first sample exercise - lots of captions for the detail-oriented. The technique itself was fabulous to learn and I hope to incorporate it into my own work, but even more importantly I learned ancient and effective ways to do finishing work. Rather than file and sandpaper, the finishing here was done with scraper and scotchstone. Big surprise is that I loved these tools! I thought they would feel mind-numbingly slow and I'd be yearning to break out my usual tools, but I wasn't. The scraper feels intuitive to use and adapts to both convex and concave shapes with ease. The scotchstone is meditative and gets into tiny corners more effectively than sandpaper.
Oh and of course you might be wanting to know how I got the red color on the copper. It is just heat-coloring - I've seen tutorials on facebook on how to do this, so the details are out there. (In general, get your copper screaming hot in a slightly reducing atmosphere, then quench immediately in hot water that contains a teaspoon or so of borax. That's it.) There were only subtle differences in technique that Ford added. Mainly, he is damn good and that's why his copper reds come out so well! If you'd like to learn more about uchidashi or Japanese metalwork in general, try Ford's new patreon page.
Although most folks would say I am in a creative field, it is actually hard to break away from the demands of fulfilling commissions (and teaching) to do new or exploratory work - i.e. stuff I'm not getting paid for! Recently I did manage to do that, and I have SNAG (Society of North American Goldsmiths) and Halstead to thank. Last fall I made the easy decision to sign up for their competition "Hidden." It works like this - enter for a modest fee, receive a box of goodies in the mail, make a piece with said goodies (plus a found object) on the theme 'hidden' by a deadline, hopefully be chosen to have your piece included in the exhibition in May. And what jeweler wouldn't want to receive a delicious box full of shiny things?? The box came last fall, and it sat on my bench, predictably, until weeks before the deadline. It lurked there, mocking me as the deadline grew closer. Finally guilt prompted me to get busy - the kits were sold out, there were people on their waitlist, how awful would it be to waste the kit??
As a mokume person, I was so happy to open the kit and find nice thick sheets of copper and brass - just waiting to be chopped up, stacked and squeezed into a billet. Those were the easy ingredients to use. Harder were the less familiar bits - most notably the sterling silver screen, the delicate chains, the tiny silver beads. I ended up using 11 of the 17 items, but I admit the beads are still in their little bag. Having pre-cut metal parts like the copper washer and silver teardrop shape was novel and certainly influenced the design process. And I discovered I could indeed sweat-solder onto perforated silver screen without melting it - that was empowering.
Well - there's lots I could say about the meaning of the piece, but I'll leave that for another time. If you feel like it, have a look at the video so you can see the 'hidden' inside and found object, and let me know what you think the piece is about. Oh, and wish me luck! If it is accepted, it will go to Portland for a SNAG-related exhibition.
SD Voyager is an online magazine with all kinds of local info and interesting San Diego stories. They recently interviewed me as part of their "San Diego's most inspiring stories" feature, along with many other fascinating business owners. It is organized by neighborhood, so I'm part of the Point Loma/Shelter Island section. Thank you SD Voyager! Read the full article online at sdvoyager.com.
Educator, metalsmith, jeweler, maker of custom mokume gane jewelry and wedding rings.