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Monday, July 22, 2013

Etching copper with PnP paper and your computer generated images.

 Etching is a great way to create your own unique jewelry components. I started with this wood carving and made a photo. I then imported this into a photo editing program Adobe CS4 to make it suitable to etch with.  In Photoshop is a filter routine called threshold. It will make a full color image into a black and white image with no gray tones. Below is the result with further modification to create a mask for etching.

 In order to get the image onto the metal I printed it and others to a sheet of PnP paper. It requires a laser or toner based printer/copier. Ink jets will not work. By grouping several images together on the sheet you can minimize waste.
 Even images with fine lines can be used, just be sure to print darkly so you have enough to mask the copper.
 The copper should be sanded with 1000 grit abrasive to give a little tooth which will hold the printed image.
 I made a sandwich of paper, PnP and copper covered with more paper.
 Make sure the copper is on the bottom and only 2 sheets of paper cover the unprinted side of the PnP. Apply a hot iron and firmly press the paper for 3-5 minutes to get a good transfer.  Make sure you cover all parts of the of the image. I set the iron on cotton, no steam.
 The copper should look like this when finished. It is necessary to peel the blue paper off while the material is hot. Allow the metal to cool and the cut apart the desired images.
 For etching I prefer this refined material over the circuit board etchants which are often recycled and not as fully effective for fine images.
 To make handling easy and to prevent the back of the plate from etching, I cover it with packing tape leaving a few inches to allow attaching it to the etching container. I use a food container with a seal able lid..
 Float the plate on the solution printed side down and tape the tails to the sides.  Timing will vary with fresh etchant 15 minutes worked well for me. It depends on your image and line size as well as temperature. You can pull the tape loose from the box to check and replace it if more time is needed.
 When the piece has enough depth to suit you, rinse it off in a bowl of water then rub it with baking soda and water to completely neutralize the etchant. Don't wash any of this down the drain.  Just discard it in a container after the water has evaporated. Seal up the remaining etchant and it will work many times. Check you local rules on waste disposal when it is exhausted.
This is my finished piece. I applied Swellegant Green Gold to the outer edges and when it was dry over coated with several coats of matte acrylic sealer. You can remove the black with mineral spirits or polish remover if desired. I like the way it highlights the pattern on this.