Monday, 19 August 2013

Electrolytic Etching–Plans and Musings–Part 1

Following on from the previous articles about Acid Etching. Now I am going to do some etching using electricity.

The principals are the same as with acid etching, however, with electrolytic etching, the atoms are separated with electrons, rather than chemicals.

You can use some pretty safe voltages and the mordant is reasonably safe (salty water) so there is far less risk to your person using this method that using toxic chemicals. Safety should still be observed, the process releases gasses. While the gasses that are released are fairly benign, you should still do this in a well ventilated space.

OK. So … the electricity source. My 12V battery charger is nowhere to be had, and I don’t want to buy another one. The solution? Make one.

I still have a large number of old mobile phone power adapters with a power output range of 5V through to 12V. I don’t need anything as powerful as 12V … so I am using an old power adapter (for something … I can’t remember what it was for … a charger for something that I don’t have anymore).

I want to be able to regulate the power, so I’m going to wire it up to a potentiometer. I also want to be able to switch it off … so a SPDT (single pole double throw) switch will do the trick. I have some parts from other electronic projects, so there isn’t much that I need to buy.

The parts list for the power supply are as follows:

  • 6.8V AC Adapter;
  • SPDT toggle switch;
  • 330Ω Resistor;
  • 3mm 5mA Red LED;
  • 10kΩ linear potentiometer;
  • tuning knob;
  • PCB perf board;
  • 2 x banana plug sockets;
  • 2 x alligator clips attached to banana plugs;
  • red and black multi-strand wire;
  • 130 x 68 x 44 mm jiffy box

(the idea for this power supply came from NavaChingEtching, although I have modified the design so suit my purposes … I don’t plan to run the etcher from batteries).

I have some testing and soldering to do first, so I’ll post some pictures later when I get the device working.

As I have mentioned in other posts, I’ve had some success with electrolytic etching steel previously, but this time I want to etch brass so I’ll walk through the process in some detail so that others can benefit from my mistakes.

To recap on the process … design, print, transfer, remove paper from work piece, connect work piece to the positive (+) rail, connect a conductive piece to the negative (-) rail, immerse work piece and conductive piece in salty water, power up, bubbles and etching happen, power off, clean work piece, enjoy your success.

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