Making Mixed-Metal Jewelry, Part 1: Etching Copper with Lexi

	After you've etched the copper, you can turn your designs into anything you like, such as etched copper cuffs.

It's not a deep dark secret that copper is my favorite metal to work with. It's fun to hammer, and it takes a gorgeous patina. The earthiness of it mixes well with my archaeologically inspired jewelry, so copper etching is one of my favorite things to do. Also, the big joke around my studio is how incredibly low-tech I am. (I am an archaeologist–I do things the old-fashioned way! No "bubbilizers" or fancy gadgets for me. The old ways are the best!) But I also love the mixed-metal look of copper and silver and the way copper warms up the coolness of silver. So join me as I use a super simple way to etch an Arts & Crafts design onto a necklace I'm making for an upcoming show at a historic home here in Denver.  

By using these easy-to-follow techniques, you may etch copper, brass, or even aluminum. This one technique is so easy, can be done in your kitchen, and adds such interest to your jewelry. And you can etch virtually any image! You may photocopy an image, photograph, or line drawing onto the PnP paper. You may also draw your own design on paper (I've suddenly fallen in love with Zentangles!), and then photocopy that image onto the PnP paper using a laser photocopy machine. (If you don't have a laser copier, Kinko's will photocopy your designs for you.)

Materials

PnP Paper Image Transfer Film
Powdered Ferric Chloride
agate burnisher (preferred), other smooth burnisher or spoon
15-micron 3M Finishing Film (sandpaper) or green scrubbie
nonfiberous Scotch packing tape
shallow dish, never to be used again for food
plastic spoon
Sharpie marker
nonacetone nail polish remover
Citrasolv (optional)
paper towels
electric griddle or ceramic-top stove
baking soda and water in a disposable container
craft stick or wooden chop stick
emery board for acrylic nails
laser photocopier/printer
protective clothing: apron, latex/rubber gloves, safety glasses,
fan or other adequate ventilation

Steps

1. Clean your metal first by sanding it with the green scrubbie or 3M paper. Make sure any fingerprints and oils are off your metal and the water "sheets" off cleanly.

2. Photocopy your image onto the dull side of the PnP paper. (You will have to explain this to Kinko's if they do your photocopying.) The image will look dark blue because of the absorption of the ink onto the paper. That's what transfers onto your metal. Note: If there are any unnecessary "fills" in the negative space areas, they may be lifted off with packing tape. Simply apply the tape to those affected areas, and then pull it off. This will pull all unwanted inked areas off the metal. If there are parts of the design that do not copy, you may fill those in with the black Sharpie.

3. Cut the image out of the PnP paper, but leave a border of approximately 1/4 to 1/2 inch around the image.

4. Heat the griddle to approximately 250˚ F degrees.

5. I previously taped the image to my piece of copper, but sometimes the tape melts and gets "yucky" (one of those precise jewelry terms) and sticks to the griddle. So now I just hold one end of the copper down on the griddle with a paper towel and burnish the other end with a burnisher or the back of a spoon. (I like the agate burnisher because it doesn't get hot.) The image will soon adhere to the copper. Burnish down the entire pattern. Take care not to press too hard on the negative space, but concentrate on the darker part of the pattern. You will see a change in the image on the paper as it adheres to the copper.

6. When the image appears dark, the metal can be removed from the griddle. Let the metal cool; then the paper can be gently peeled away from the design. Use caution when doing this, and remove the paper slowly.

SAFETY IS MOST IMPORTANT HERE! READ CAREFULLY! WEAR SAFETY GLASSES AND RUBBER GLOVES!

7. In a shallow baking dish (I use an 8 x 8 glass baking dish) make your ferric chloride solution by adding the powdered ferric chloride to the water. Add the ferric chloride to the water. The water will cool off the solution, and there will be some chemical reaction, some heat and smoke. That's why you want to add the acid to the water, not vice versa. (Remember it as coming in alphabetical order, "A"cid first into the "W"ater . . . A before W.) Stand back and do not breathe the fumes.

Note about mixing the solution: I don't do anything like "so many cups of water to so much acid." I go by color. If you make your acid the color of weak green tea, it will take a long time, possibly up to 4 hours, for a good etch, but it will be a very beautiful etch. If you make it the color of cola, it will take about an hour to etch. I use the cola color and achieve great results. Anything darker takes less time, but it may be a very uneven etch with rough design edges or undercuts. So add the acid to the water and stir with the plastic spoon (or it will stick to the dish) until you've achieved the color you want.

8. Cover the back of your metal piece with a layer of the wide Scotch packing tape, which holds better than other tapes, and allow enough tape on each end to attach to the sides of the dish and over the side by a few inches.

9. Suspend the metal design-side-down in the solution, not allowing it to touch the bottom of the dish, yet allowing it to be submerged into the ferric chloride. More than one piece can be done at one time. Sometimes some of the ferric chloride will seep under the tape. I haven't found a way to keep this from happening, but it usually doesn't bother the back of the piece too much. 

Note: Some teachers tape pieces of Styrofoam to the back of the copper pieces so the pieces float on the acid. I'm still trying to perfect this technique . . . stay tuned.

10. Periodically jostle the solution, or stir it with a craft stick or wooden chop stick about every 15 minutes. After 45 minutes or an hour, check the metal by removing it from the solution and holding it at an angle to estimate how deep the etch appears. You can run your fingernail over the design to check the depth of the etch, too. Wash your hands well.

11. When you've achieved the desired depth of the etch, remove the metal from the solution and put it in the baking soda and water solution. See below for what to do with the ferric chloride solution.

12. Remove it, dry with paper towels, and then scrub the surface with nonacetone nail polish remover and a green scrubbie or 3M Finishing Film to remove the ink. Tip: Something that works great, thanks to the advice of my good friend and student, Marletta, is Citrasolv. It removes the PnP ink better than anything I've ever found! It's available at Sprouts or your local health food store. Try it, you'll love it! I promise!

13. I finish by sanding the piece with some 3M Finishing Film, which creates a soft finish. File or sand the edges with an emery board used for acrylic nails and use your burnisher to bring a high polish to the edges of the piece.

Now that the etching for part one is done, next we will attach it to a silver back plate and finish off our necklace, on Friday. "Tune in next time! Will Lexi be able to solder two different metals (copper and silver) together without them melting? Will the bail attach properly? Will the pendant be on a chain or beads? Tune in to find out!" (Bullwinkle fade out music here.)

Have fun, be safe,
Lexi

NOTE: How to Dispose of Ferric Chloride Solution
You may not put the solution down the drain because of residual copper ions left in it. Allow the solids to settle, pour off the liquid into another container, and add water to dilute it; then it can be poured down the drain. The residual sludge left in the dish should be poured into a plastic container, sealed, and disposed of at the local hazardous waste disposal facility. Take care to store in a covered container so it will not be available for pets or small animals to get into.

Resources
PnP Paper Image Transfer Film: Reactive Metals
Powdered Ferric Chloride: The Science Co. 303-777-3777

Need more info? Check out Lexi's other etching tutorial. Prefer to watch and learn? Check out Lexi's video tutorial, Jewelry Etching on Copper DVD or instant download.