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I Forge Iron

Electro Etching Cheap & Simple


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Thought I would share my experience with developing a cheap simple way to electro etch my makers mark.
Now my process is not new and is well documented elsewhere on this and other sites, however I found that
all variations of this method required the use of either purchased machines and or expensive stencil materials.
Even a battery charger is not that cheap today, so my goal was to build a etcher using cheap, easily available items.

ETCHER UNIT
etcher_box.jpg

Although I have used a huge heat-sink on the bridge rectifier, I doubt that such a large one is necessary.
All you need to do is allow the rectifier to dissipate any heat, so any chunk of aluminum will do, couple pieces of
angle bolted together.
The transformer is center tapped with two secondary windings 9-0-9 ignoring the center tap you have
18VAC / 20VA. I used this as it is fairly common and very cheap.

Technical Spec
Primary Input: 220VAC
Secondary Output: 18VAC (9-0-9) 20VA (1.1A)
Output Switch Position 1: 18VAC 20VA (1.1A)
Output Switch Position 2: 25VDC 20VA (0.8A)

ETCHER SCHEMATIC
etcher_dia.jpg

The circuit is very simple, take 220vac from public supply, step it down somewhere between 12VAC - 24VAC
1A - 2A is sufficient to do what you need to, the lower the current the longer you need to apply the probe.
Take secondary output of transformer to bridge rectifier input and also to one side of double pole switch.
Take the DC output of the bridge rectifier to the other side of double pole switch.
You now have a etch unit that can etch with either AC or DC

PROBE
5mm threaded bar, 5mm SS plate (sized to just bigger than touchmark)
Small square of felt
etcher_probe2.jpg
etcher_probe1.jpg

SOLUTION
Salt / Water (saturated) just keep adding salt until water stops dissolving it.

STENCIL
I have tried photo resist spray, fancy silk screen material and every other way suggested on the web.
All are expensive and have varying degree of success, solution VINYL, again not a new idea. Every town
has a sign writer / label maker etc. The technology is cheap as are the materials. All you need to do is
be able to produce a negative 1:1 size, high resolution image of your touchmark. I used a free open source
graphics software called Gimp and also Inkscape to create a vector image as a .svg file.

etcher_vinyl.jpg

My local vinyl cutting company, uses a laser vinyl cutter, this is the best way to get clean small detail.
They make a lot of vinyl stencils for people who do acid etching on glass, and yes you could probably use this
and etch with acid, have not bothered as electro etching is cleaner and safer.I had them cut a sheet of stencils,
cost R1.77 per stencil, your money ($0.24) had to buy a minimum of R150.00 worth ($21.00) This gave me almost 100
stencils, and even though they are one shot, it is still cheaper than any other method (besides stamping)

USAGE
To use:
(if DC) attach red +DC clamp to work, black -DC clamp to probe.
(if AC) does not matter

Wrap new felt square around probe plate, fix with rubber band.
Shake solution, use eye dropper to wet felt
Set AC/DC, apply probe to design, do 2 - 5 seconds max at a time, check then reapply until finish/depth achieved

AC OUTPUT:
Does not etch as deep, blackens etch.
etch_ac.jpg

DC OUTPUT:
Etches much deeper, not as dark, looks like acid etch
etch_dc.jpg

BLADE EXAMPLE
What it looks like on finished blade
etch_sample3.jpg

Thats it, cheap etcher, cheap stencils, excellent result!
Sorry for the crude schematic, if the circuit is not clear give me a shout.

Jeff

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Thanks for sharing that. I look forward to giving it a try.

One thing though... is that really 220VAC coming in or did you mean 120?

Don


Yeah! here in deepest darkest Africa we can only afford 220VAC, 120VAC is too expensive, the cost
of an extension cord from USA is prohibitive.

:D:lol: sorry could not resist

But you right I should have said something about local supply, but for all you 110 volters the same rules apply.
The truth is as long as you end up with 12 - 24 volts at 1 - 2 amps it will work. The closer to 2 amps the better,
but as I said if lower you will just need to apply probe that much longer.
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thats nice might have ta try that ! looks too easy tho...gota put a flux capasitor in there somwhere...hehehe!

I too live in deepest darkest and I RECON IT WOULD BE A HOOT IF YOU JUST USED YOUR COMMON OLD ELECTRIC FENCE ENERGISER :D:D:D

Jeff if you are interested I'm in Uhmlanga with a seriously under utilised vynil cutter, if you ever need to play feel free! B)
Ian
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Hi Ian

Hey great to find another local knifemaker/blacksmith here in Durb's, I am in in Morningside, I thought they only existed "up there" in Gauteng.

is you cutter laser? in my experience the normal vinyl cutters dont do too well with small fine stuff, but then I know XXXXXX about
vinyl cutters.

Jeff

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Jeff,

I am not into knives as yet, but I HAVE QUITE A BIT OF Stainless steel 2.5 to 3mm toughened armour plating left over from a job at O.R.Tambo airport probably ideal for knives,its shiny hard as blazes(cant bend it in 80T pressbrake) magnetic but cuts well with laser and 0.9mm cutting blades. I have a guy comming down from my Joburg shop on Monday I'll get him to bring down some off- cuts that you are welcome to.
If you need things like acids/ Borax etc. let me know and I can organize for you! :)
Ian

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I have thought about the vinyl myself, but instead of doing the felt and SS rod, I have used a cotton ball, soaked in supersaturated salt water, and one of my leads just stuck into the wet cotton ball.

I love how clean your etch-marks are and think I may have to visit the local vinyl shop very soon.

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  • 7 months later...

Hey sorry missed the last post :(

Car battery is a great idea, simply, commonly available, big current 50 - 150amps depending on battery size.

The only minor downside would be the lack of AC and amount of control you can exercise with limited lower current,
etch a bit stop, etch a bit stop. With the almost unlimited current means you need to be very careful as you
can weld with that sort of current.

So if you are happy with DC only result, and can work carefully then a great, simple alternative to buying or building.

Good one :)

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  • 8 months later...

I whipped one of these up for about US$50. Everything from Radio Shack, including an enclosure, contacts, etc. (Well, I did have wire, cord, plug, and clips already)

I probably could have halved the price by not getting the nice, user friendly stuff and doing a less nice job...

Well, since I don't have a mask right now I used nail polish, let it dry some and scratched into it with a metal point. I let the polish cure for a few minutes more, and etched it in. My results were excellent on the etching, and mixed on the nail polish mask. The nail polish was not fully cured and where there was surface contamination (fingerprint) it peeled making a bad etch.

Now to have work that needs marked, a better way to mask the work, and a suitable maker's mark. My signature is sloppy and variable so I don't really want to use that! The etch is deep enough after 5 seconds to feel depth to it!

My open lead voltage is about 24V DC, and 27V AC.

I really want a blinky light so I know it is on, and what it is set to. That is as simple as 2 LED lamps, set opposite and connected, with a current limiting resistor tied into the output jacks. When it is DC one LED will light, and for AC both will light. I didn't put this in because I didn't have the resistors on hand. It will be simple to add it later.

Phil

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I played around with electro etching a while back for giggles. Living in cold country everybody has a battery charger and you can get them at garage sales any saturday. Anyway, I used a rubber stamp to apply the resist. . . Nail polish that is. Salt water electrolite and got decent results. I'll have to give it a shot again if I come up with a product to mark that is. <grin>

Oh yeah, Alaska is only deepest darkest in winter, summer is lightest brightest. In truth we average the same amount of possible sunlight as anywhere but it's cool as all getout to see folk playing frisbee at a BBQ at 1:00 am.

Frosty The Lucky.

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I played around with electro etching a while back for giggles. Living in cold country everybody has a battery charger and you can get them at garage sales any saturday. Anyway, I used a rubber stamp to apply the resist. . . Nail polish that is. Salt water electrolite and got decent results. I'll have to give it a shot again if I come up with a product to mark that is. <grin>

Oh yeah, Alaska is only deepest darkest in winter, summer is lightest brightest. In truth we average the same amount of possible sunlight as anywhere but it's cool as all getout to see folk playing frisbee at a BBQ at 1:00 am.

Frosty The Lucky.


Rubber stamp huh? I'll think on that one. Might be the easy answer!

I was figuring on calling up the sign maker and seeing what he can run through his laser cutter for me...but I still need a mark or logo.

Can always do my name I guess. It is to the point at least...

Phil
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Im sorry but could some one make this ridiculously easy for me? I live in the US and would be using a battery charger, either one for a large Car/motorcycle battery or a small Rc-up to 10 volt battery charger. And if this not be enough juice someone please let me know. Thanks

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Im sorry but could some one make this ridiculously easy for me? I live in the US and would be using a battery charger, either one for a large Car/motorcycle battery or a small Rc-up to 10 volt battery charger. And if this not be enough juice someone please let me know. Thanks


Yes, but you need an older type charger to do this with. My charger is too smart and turns itself off... The electro-etch machine I built is rated to 2A on the transformer.

Phil
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As Phil says, you are effectively putting a dead short on the charger when you connect
both + & - to the blade, so any of the newer chargers will have some sort of short circuit
and current overload protection.

So your choices are, an old charger with no protection, which will try and keep on working
even with a dead short on it, or build one as shown in the OP.

I am afraid that if you are unable to build it as shown, then you are probably safer buying a
dedicated unit. After all you are working with mains supply voltage, so be careful!

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You don't need a lot of amps. My transformer is rated at 2 amps. You need something that will provide voltage whether there is a voltage or short being drained from it. My electronic battery charger is too "smart" for this, and turns itself off (sometimes much to my annoyance) when the drain is too low of voltage (such as a really run down battery), or short.

Phil

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Well, since an LED is already a diode I don't think I will need an additional diode as long as my current is adequately limited.

I will try drawing it out. The image I have is too large to post here. I can't even attach my scan of the Radio Shack receipt.

Phil

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Excuse my drawing. GIMP is great, but I am not god with it. This "box" goes in between the outputs One LED would be lit for DC, both for AC. Since these are diodes, it should work. The limiting resistor is 1K ohm 3A, according to an online limiting resistor calculator I used.

Phil

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