Etching (part 2)
By Fearless Fabricator on Thursday, April 9th, 2009
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Electro-Etching or the electrolytic technique of etching is basically the same process as when one over charges a galvanic cell (as in a lead acid car battery or a cell phone battery) except here one wants corrosion, but warping and shorting out is still bad. This step requires a 12 volt power source, for example a car battery, a car battery charger or a converted ATX computer power supply. I use the latter, but if you a going to use a battery I suggest two things. One, remember car batteries have more than enough amps to kill you and, two, you should put a switch in the positive line to avoid sparks when controlling the current. I use 14 or 12 gauge solid copper wire for a anodes in the bath. I place about two or three for a small bath. The work piece itself is the cathode. You’ll need a clear vessel; I use a bottom ¾ of a water bottle for etching in, a mason jar for mixing the solution in, an old tooth brush, some jumper wires and copper sulfate. Copper sulfate, you say! Where the heck do I get !*?#@ Copper Sulfate. Well one needs look no further than the hardware store in the plumbing section. I bought root kill, but any similar product should work if you read the label.
To start, fill the mason jar about 2/3 full of warm. Add copper sulfate crystals and stir until no more will dissolve into the solution. After letting it sit, I found that further stirring allowed the some of the undissolved crystals to dissolve. So I added more and repeated the process, for the more copper sulfate in the solution, the better it will work. Once I was happy with the solution, I racked it off into the etching vessel, leaving the slurry of crystals behind.
Now that the solution is ready, I use an alligator clip to attach the positive power feed to the work piece, then submerge it into solution. I leave a tab on the work piece so that the clip itself is not in the solution. Next I place the anodes into the solution and clip the wire to the negative feed. Keep the anode and cathode about 1 inch or so apart. Energize the bath and the process should be visible. Hydrogen bubbles will appear and brown oxidation form on the anode.
Oxidation gathers on the anode, so to keep the process optimum, the power can be turned off and anode can be clean with a toothbrush. The cathode can be cleaned similarly but one must be ginger. Because of the amps involved, resistors are an expensive option to limit the power flow, but I have been told that one can use 12v light blubs in series, for this purpose. I am of the more power, not less, school of thought, so I have not tried this.
Once the desired level of etching has occurred, power off, disassemble and it’s time to clean the piece. Carburetor cleaner seems to remover the toner, but I would like to find a less broad, less harsh solvent. The solution itself can be reused. If let to set the oxidation will settle and you can rack the clean solution off of it. The oxidation, after evaporation, can be used with varnish to make a metallic paint. I wonder if Madam could use it to retard the growth of roots in non-food production plants?
Avoid hot electrical connections (by using power switches), open flame, and work in a ventilated area. Don’t blow this off. Why? BECAUSE THIS PROCESS GENERATES HYDROGEN GAS.
Remember, this process is using amps of power. Amps, not volts, kill and one amp is enough to stop your heart. Minor shocks can cause muscle contraction. While a entertaining effect, these a can lead to other accidents due to failing limbs. If you feel cavalier enough to work with live voltage do as a mentor taught me, one hand on your work, one hand on your belt.
Other ideas I have yet to experiment with. Notice the untested bit, please. I was wondering about having different sized anode plate, instead of just wires, and their ratio to the work piece. Trying hot water for making the solution. Also I have been do some reading about using a small aquarium air pump and air stone or similar ideas to keep the solution agitated, to speed up the process. More on this when inspiration hits.
Hmmm … electrically generating hydrogen gas….. Something I probably will not ether journal on.
Two good places to start your own research are:
http://www.greenart.info/galvetch/contfram.htm
Jake von Slatt ‘s, 01/10/2007 post http://steampunkworkshop.com/electroetch.shtml
Part one of Etching may be found here.
- Etching brass and copper - Part One.
- Etching (part 2)
Tags: brass, copper, etching, fabricator., fearless, goggles, Phineas, project, punk, steam, steampunk
