Poor Man's Etching Power Supply II

We've made the power in Part I, now let make the interface.

For the switch plate, I used a small piece of polycarbonate and drilled holes for the  switch and leads. You can use whatever plastic you have. Drill the switch hole for 1/4" and the electrical connection holes to 3/16" or to suite whatever machine screws you have. 6-32 or 8-32 machine screws will be fine.
Now that we know it's going to work, it's time to epoxy up the adapter case. Mix enough 5 minute epoxy to reassemble the adapter case and a little more to attach the switch plate.
Switch plate is glued in place with 5 minute epoxy. Wait please.

I made some labels for the unit. Pardon my humor. These are simple permanent marker on duralabel from sheet Avery.

Here we see the underside of the etcher. I used some electrical tape to secure the wires. This really only prevents them from getting caught or hooked one something.

The Pad

The Pad is what makes contact with the steel to make a complete circuit. The pad is usually made of stainless steel and covered with felt that contains an electrolyte solution.

Here's the start of my pad. Some 1/8" stainless steel cut to about 2" long by 1/2" wide. We need to drill a hole in the steel and counter-sink for the screw do that the screw head is pretty much flush with the steel. A light grinding will make the pad surface flat.

The wood size is determined by what length of SS screw you have. I had some 1-1/4" SS screws handy so I made the wood 1" for the pad handle. I used 1/2" x 2-1/2" teak and cut it to 1". Then drilled a 3/16" hole for the machine screw to go through.  Once the hole is drilled, screw the etching plate on, tighten and shape the whole thing to make a nice pad package.
A washer is used to firmly connect the steel to the wood. Leave about 1/4" for connecting the wire with a nut.
We need some connections to be made. Here I have 1 red alligator clip and two red ring lugs.  Note how I have sanded the screw head flush on the pad. This will make the best connection.
A handy piece of 18 gauge appliance wire will be my leads. One of the wires has a rib running down the insulation so you can keep track of which wire is which.
Here I strip and crimp two red ring lugs on the appliance wire. I then attach them to the etcher. 
At the other end of the leads, attach the CLIP (going to the CLIP wire) and a ring lug for the PAD (going to the PAD wire).

Here's how I connected the Pad.
I decided to solder the Clip wire to the clip. You can wrap the wire around the screw and tighten the screw to make a good connection. For me, soldering is easier.
Now, prepare some felt. This is dollar store felt. It needs to be cut to make a suitable pad. The piece I used was about 4"x5 and I cut it out from a full piece with plain-old scissors.
Fold the felt in half (double the thickness) and tie around the pad with a cable tie or heavy rubber band.
The pad should look something like this where you are done.


Unknown said...

Question I have a plug that puts out 22vdc will this work and what would be the difference from a 12vdc

D. Comeau said...

Hi Dustin,

The 22 VDC adapter will work, but you want to be making shorter contact times. Longer time (> 5 seconds) may scorch your stencil.


Unknown said...

Hi Dan.
Thank you for a wonderful and very informative site.
(Just ordered my Ruixin knifesharpener, and am waiting in some exitement ;-)
I'm trying to pluck up courage to start on my own first knife.
I had never heard of or know of etching before reading this article.
I don't understand why you switch between alternate current and direct current?
Found a video on youtube about it, and this guy makes what I believe is a good result with much simpler means.
What's the advantage of switching between AC and DC?
I sincerely hope to hear from you
Please keep your fantastic tutorials coming, they're great.
Best regards from Denmark.
Houle Bækdal