New Electro-Etcher design

Its not a computer power supply it is a pump power with a built in 120v - 12v transformer. I previously used it straight to aligator clips to etch a couple of blades.
 
any chance you have another source for the 6v/12v AC stepdown transformer? ebay isnt pulling any thing for me, nor radio shack
Thanks
 
I don't know about a kit, but I took your core concept and adapted it a bit. I already had a model train transformer sitting around with good solid ac and dc 12v outs, independent from the train power. I tested and they produced good marks so I used a project box and switch, connected the ac and dc in to the switch and then the switch output to a small mono phono jack. Then i attached the matching plug to the leads of my current etching pad and clip. I discovered that my chosen jacks were VERY touchy about the soldering and with my overkill wire it took too much heat for the poor little jack the first time so my 2 pack became a single working connector. I'll have to pick up another, and some smaller wire, to remake my gator clip pair for when I want to use that instead of the pad and clip.

No button on mine, and no power light, I guess it wouldn't hurt to add them, to at least verify output before starting to work. One for ac, one for dc and that would help confirm that I'm on the right output at well. It's not hard to remember that up is etch and down is mark, but hey, might as well do the job right.

Anyway, thanks again for the nice idea. I wouldn't have gotten off my butt and actually done it without the inspiration of your design.
 
I got everything together besides the computer power cord! Found everything I needed after I found out what the transformer was used for:) thanks for the write up man!!!
 
I made the 24v version of the Crawford etcher and it works better for me than when wired to 12v ,better meaning that it etched faster. It still took 60 seconds to get a deep etch to create a .25 diameter circle.

So I am confused about the effects of increasing volts and amps. I thought it was recommended to stay at low amps and volts because too much creates too many bubbles which inhibit etching. The Marking Method machine is 30v/30amp machine. Could someone explain the rationale of the tradeoffs of varying amps and volts.

Also, I am a blacksmith and would like to etch mild steel without polishing first. It appears that millscale found on mild steel prevents etching. I have not had good results without polishing first and was hoping to find an etchant that might work.

Thanks
 
Hmm, are you trying a single, continuous etch? Or, are you trying multiple short etches? The last time I etched, it took only about 10 seconds rapidly pulsing the etch.
 
Hello zaph1, I want to thank you for this project. That's exactly what I was looking for. Some questions about this electro-etcher:
- I don't know if I understood the way the capacitor works in this project. In your specifications, it "raises" the current to 2A? The capactior will only work in multiple short etches or in a single continuous etch too?
- I bought a 12v 2A transformer, which capacitor specifications should I use?
- Is there any difference tapping the arcade button or using the etcher turned on and just dabbing the Q-tip?

Thanks again! :)
 
The arcade button is cleaner and reduces the risk of shorting the unit when handling. I would still use the capacitors, they both boost the short term amperage as well as smoothing the circuit. Without the capacitors, the DC still operates at 60hz. With the capacitors, it is more constant and closer to 0hz. It can be used continuously, but it will have slightly less power depending on your transformer.
 
Can u make some more detaled picks im ordering the parts tom can i use 30 gauge wire and what Wire did u use To connect the jack to the transformer the thick ones
 
I wouldn't use 30AWG wire, it's too small and may overheat. I use CAT5 cable and split it into individual wires which are 24AWG. The CAT5 cable is 4 pair of color coded wires, which makes it much easier to work with. Over such short distances at low amperage, it has been adequate. Even in the 3 Amp units that I build now it has never heated up the wires more than a couple degrees. The 120vac to the transformer wires were 14 gauge in this model, but I now use the same 24AWG and haven't had any overheating issues. 24AWG wire is rated for .577 amps and this 120AC draw in this unit is only .3 amps which is plenty of copper. Coming out of the transformer there is a 3 amp 12VAC load. This has a voltage drop of only .079 volts. This translates to less than ¼ watt of heat over a 6" wire.

I would sell you an unassembled kit for $25 plus shipping if you want.
 
Is your CAT5 solid utc or stranded wire? (My guess is solid but I ask because some people might try to use stranded and not get the same results).
 
Ah cool. Thanks for the design :) Seems like we have much the same job Zaph, except you have more of an electronics background clearly.
 
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