Home-made Steampunk cogs

I like the steampunk look, and my daughter and I fancy building a steampunk keyboard.
Alongside my PCB building, I tried building some steampunk-style cogs to use as decoration or parts. I found some thin copper foil (0.1mm) from a sculptor's and restoration supplier Tiranti.

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It's nice stuff, thin enough to cut with scissors, but thick enough to cover corners and bend around shapes without ripping. It should cover keyboard edges well.

One of the things I wanted to try was to use PCB etching techniques to make complex cogs or clockwork shapes. I put together a couple of templates (see the end of this post) and tried a few things to transfer the toner onto the foil - the best technique ended up being the label backing paper as per PCBs. Because you need to cover both sides, I mirrored the label and folded it in half - then placed the copper foil inside the transfer.

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A couple of passes through the laminator, and the toner is fused onto the copper. I also printed a more complex mechanism onto normal PCB board.

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I then used standard ferric chloride (PCB etching fluid) to etch the copper. You can either dunk the boards and gently stir the etchant, or (with GLOVES) rub it on the board with cotton wool or a kitchen towel.
Etching the PCB was pretty quick: etching the foil all the way through took a about twice as long as the PCB board. The etching worked well, most of the complex detail and cog teeth coming out well.
However, the toner is much more difficult to remove. With the PCB, the board gives the copper plenty of strength so the toner can be scrubbed away. With the foil cogs, they tear easily, so you can't scrub them. I tried soaking in acetone (nail varnish remover) and this removed some, but not all the toner. An agitated acetone bath (maybe an ultrasonic jewellery cleaner?) might remove more.

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The normal PCB came out very well. The detail is good and the board can be scrubbed to remove all the black toner.

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One of my ideas was to place some LEDs behind the PCB to shine through the board, illuminating the hidden pattern: this backlighting does give a really nice effect (shown against a normal lamp).

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A nice large panel with plenty of clockwork mechanisms would look good instead of a numeric keypad, or as a lit panel in a PC case. Layers could even be stacked for a greater 3-d effect. This is just the research so far, I'll post more as it proceeds.


How to make a gear template (examples)

1. Generate a gear at woodgears.ca - I used tooth spacing 6mm, gear 1 teeth 100, spokes 5 and show spokes on.
2. Hit the 'print' button, then OK. My mac then allowed me (bottom left PDF dropdown) to import the PDF into iPhoto, basically exporting it to a jpg.
3. Edit the picture in Gimp. I did the following operations:
   
   1. Fill the outline with black
      
   2. Use Select - by color and then click on the background (white)
      
   3. Use Select - shrink to shrink the selection by 20 pixels (not from the image border)
      
   4. Use Edit - Fill with FG colour to fill it with black
      
   5. Use Select - all and Edit - copy
      
   6. Use Image - Canvas Size. Click the 'link' between the width and height to unlink them. Double the height and add two pixels.
      
   7. Click Image - transform - flip vertically
      
   8. Click edit - paste as - new layer. This should give you a mirrored image top and bottom, with a small line between them.
      
   9. Click file - save and export when prompted.
      
4. Laserprint onto label backing paper, heat transfer to copper foil, and etch.