Make Heat-Patina Designs on Copper Using Gel Flux and Rubber Stamps

Possibly more than making jewelry, I enjoy experimenting, testing new products and techniques, making samples, trying out ideas. I think that kind of "play" is where great ideas are born, when you have no goal in mind and just enjoy the materials at hand–and in your hands. I love having a little spark of an idea, either from my own creative subconscious or learned from a creative friend, and then running with it to see where it will take me.


In this case, the spark of an idea came from Mary Hettmansperger in her two-day master metal jewelry-making class at Bead Fest last year. We used gel flux as the "ink" and rubber stamped with it onto sheets of metal, particularly alternative metals like copper. Then we heated the metal in a torch flame, just like you do when creating a heat patina. Because flux protects the metal from heat, it prevents (to varying degrees) the metal under it from forming a heat patina while the metal that isn't fluxed changes color in the flame's heat (as shown on the left). It was such a fun way to create patterns and unique patina designs on metal sheet! I couldn't wait to get home and try again.

Well you know how that goes–it took me months to get around to it again, but I did recently and it was even more fun than I remembered.

Here's what I did: I didn't have any gel flux, so I decided to try adding a smidge of water (exactly a smidge) to regular paste flux that was just a little dried up. It wasn't totally dry, but really firm in the jar–if yours is more or less dry, adjust the water accordingly.

I'm just kidding about the exact smidge part, of course. I actually added enough water to turn my flux into the consistency of sugar icing, just a few drops at a time, stirring all along and mashing the larger chunks to break them up. I did this in a small tin with a very tight seal; use whatever container you like, but a good seal is important to prevent spills and future dry-ups.

Once I had the consistency that I thought would work, I applied it to a variety of rubber stamps two ways–by dabbing the stamp into the flux mixture (just as you'd dab a rubber stamp onto an ink pad) and also by brushing the mixture onto a stamp with a craft paint brush.

The rubber stamp above created the heat-patina design below. It's not an exact representation, of course, but I love the result.

Then I stamped on my copper sheet scraps and held them in the flame until the flux bubbled and turned dark, the copper glowed red-orange, and the liquid pretty much burnt out of it. Then I quenched the copper in water.

Here's what I learned:

  • Try your best to stamp straight up and down onto the metal. Fluxed rubber is pretty slick on metal sheet, as you can imagine, making it a little difficult to not slide and smear. If you mess up, just wipe it off and stamp again.
  • It doesn't take a lot of flux to impart the design onto the metal. Just like rubber stamping with ink, stamp off a time or two on a paper towel or piece of paper to remove excess. As long as you can see the wet, slightly milky design on the metal, it'll most likely work well. See below for how different amounts of flux create different effects.
  • Naturally, stamps with large clear or simple designs work better, or at least more like the stamp, when the process is over. Stamps with smaller, detailed patterns don't keep their designs so well, but they do make unique and interesting patterns.
  • Letter stamps didn't work so well, but my rubber stamp alphabet is a serif font. A simpler, sans serif font would work better I'm sure.

Top row, left to right: finger dabs, a harlequin-design rubber stamp, a very detailed rose stamp (that obviously was too detailed, but I like that result), and part of a stamp with script writing on it. Bottom row, left to right: finger swipes, dabbed on and off with a paper towel, alphabet-stamped word, and painted cross-hatch lines (the result of the flame example above).

After trying the rubber stamps, I moved on to painting and finger painting, drawing flux squiggles and dots on the copper sheet. Fingertips and paint brushes leave a little thicker deposit of flux on the metal, which create differing degrees of protection from the heat, making different colors on the metal. The bright, shiny copper areas had the most flux protection; the red areas were protected but less so; and the darker areas had little or no flux protection from the heat.

NOTE: Remember that flux is toxic if ingested or inhaled, so work in a well-ventilated area. The harmful element in flux generally isn't absorbed through the skin, but if you have any finger cuts (or just to be safe), wear rubber gloves for this part or stick to the paint brush–the result is the same. Take extreme care to protect your eyes, as always when working with flux.

I might've had slightly better results (more crisp, clear designs) if I'd waited until I had gel flux, but I'm a little too impatient for waiting when I get an idea to try!

If you're in love with creating patinas and special effects on metal, you will love Matthew Runfola's gorgeous book, Patina: 300+ Coloration Effects for Jewelers and Metalsmiths.

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