Sanity check on DIY etching device

J

Joakim Lööv

Joined
Apr 18, 2017
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96
I'm planning on making my own etching device but need your sanity check on it so I (a) don't kill myself, (b) blow a fuse or fry the included components and (c) manage to etch hardened carbon steel. Me idea is to re-use an old 12V transformer, as follows:

230V/50Hz/AC wall socket (behind a 10A shared fuse) -> non-grounded wall plug -> 220-240V/50Hz corded dimmer (3-100W) -> 240V/50Hz 12V/AC transformer (dimmable, for 10-60W halogen lamps, max 5,3A) -> isolated alligator clamps (one + and one -)

eh? :)
 
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I can't help with that and maybe somebody will chime in that understands it but until then

I made an etcher using Chirs Crawford's plans. If you google it his detailed plans are on his website.
 
For sure you don't need a 5 amp fuse, try a 1 amp instead. Also, you don't really need a dimmer to adjust the voltage from a 12vac xfrmr. Perhaps 15 to 16 vac is all you're going to get from that, but it should work. You also MUST have a diode bridge to convert the AC to DC, and best to have a 100µF capacitor to help smooth the DC - not totally required, but a good idea. You'll want a switch to switch between DC and AC voltage for etching. The DC will "remove" the metal to create the image, while the AC will make the image black.

As mentioned about, find Chris Crawford's schematic to better info to build the etcher.
 
Thank you for your feedback! Based on it, I'll:

1. remove the dimmer
2. stick to mark the metal using AC for now (can add a AC/DC switch later)
 
I'm not sure how well the AC will etch - the black might just be laying on top of the metal easy to wear off. The DC puts a "trench" for the etch, the AC then lays a black layer in the trench with the depth of the trench providing protection for the black. Understand, then "trench" might only be 1 or 2 thou deep, but doesn't take much.

I've done a DC etch, then painted over with a black permanent magic marker to fill the etch. Using a flat board sand with 800 grit or so to remove all the black marker leaving the black in the trench to get a nice black looking etch.

Try the AC and see how well the mark stays with rubbing.
 
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