This instructable covers how to etch a knife blade.
Modern knifes are often made from stainless steel and other corrosion resistant materials. To encourage etching electricity can be used. Don't worry, 9V is enough!
Etching is different from engraving. Engraving is usually scratching fine lines into the surface of the material, whereas etching chemically removes material, possibly until a hole is created! Etching can often go deeper than engraving.
I should mention that I got the information on how to do this from this site , it came up from a google result and gives you the basic info on how to do it. I've added pictures of my experience to help you along the way
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Signing UpStep 1: Materials
You're going to need:
-nail varnish (paint may do instead),
-acetone (nail varnish removed or other cleaning solvent might do),
-cotton buds,
-water,
-salt,
-a 9V battery,
-croc clips,
-a scribe or pin,
-the object to be engraved,
-a dish to do it in.
-nail varnish (paint may do instead),
-acetone (nail varnish removed or other cleaning solvent might do),
-cotton buds,
-water,
-salt,
-a 9V battery,
-croc clips,
-a scribe or pin,
-the object to be engraved,
-a dish to do it in.
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do you have to apply that voltage or you could do that with a car 12v battery? can u use more or less current? and what are the results os changing the voltage?
thx
I'm afraid you really need to experiment for your self as I haven't specified amount of water to amount of salt ratio, nor do I know which battery your using I can't be more specific. All this will affect how long you need to do it for.
It certainly shouldn't take as long as 10 mins.
I guess you could but I think you'd have poor resolution. If you can imagine the nail varnish resist only work on the surface. Once you've eaten in to the metal a little, the side walls of the trench you're etching aren't protected by the resist. This would allow the edges to eat away, possibly even undercutting the initial design.
If you're trying to do it to something very thin it might not be a problem but I suspect anything over about 0.1mm is going to show noticeable pattern degradation. Experiment I guess.
Also don't forget the middle will drop out of characters like a, e, o, p, d, 0 etc.
You'd have to have supports like when you stencil
Very cool. Thanks!
I'll check on the amps when I get home tonight and let you know.
Typically the ESD (electrostatic discharge aka ‘Static Electricity’) 'human body model' testing is 8,000V touch and 15,000V air gap. This is used to test electronics for susceptibility to ESD. You rub your feet on the rug and zap a sibling... that's a very respectable amount of voltage that you just generated.... but there is essentially no current and "Current Kills"... It only takes something like 6-20mA (don’t recall the actual amount) through the heart to kill. Wall warts typically supply 250mA to 2A. Batteries will source all the current that they can. As long as there is minimal resistance along the path of electricity and you send 20mA through the heart... DANGER is possible. Using an electrolyte rich fluid (like salt water) and placing your hands in a bad way, it could very well put you at risk. Granted your skin will act as impedance... but it all comes down to Ohm’s law.
What I think ‘_soapy_’ and ‘laserage’ are discussing further down is if a bad setup is there and the cheap little wall wart is past its nominal operation… it could have problems and source more power than a battery could. Given how cheap those things are, that is definitely a possibility.
Like I said, my 2 cents... ehh maybe my 1.5 cents. =)
In your experiences, is this more of a slow swipe over the blade or a several minute operation to get the etching deep enough?
Just use a battery or two, it is far safer. Also, you might kill the wall wart if it can't put out enough current.
And I've got such a pile of wall warts left from old cellphones and CD players, I'd be okay roasting one or two to make a cool blade like these.
If you want to move up to etching simple graphics, you can use the toner transfer method (the same as PCBs) to transfer toner to the blade for use as a resist.
When I do the etching to my knifes I use a professional stencil that is cheap if you plan to do the same logo on all of them.
Instead of the varnish you could also dipthe blade in liquid candle wax.
Another way is to iron a reverse printed image on it, but I have no experience in this.
As for the polarity:
- Positive to the blade: removesa bit of steel so the image is engraved
- Negative to the blade: electrons flow the other way round so they oxidate the pattern magint it black.
So you can use them both in this order if you whant to have a deep (microns) engraving with black content.
I didn't have much luck reversing the polarity, it just seemed to lift all the nail varnish off. Further investigation needed on my part :)
I guess you can make the resist/nail varnish out of any half decent insulator that is easy to apply, pattern, and then remove. Candle wax would do away with the need for acetone as well!
I'm going to try this using vinyl transfers rather than nail polish as I can CNC that far more easily than I can CNC engrave a curved steel blade.
NaCl = Table salt
Electrolysis of Aq. NaCl
+end = Cl
- end= Na
the chlorine gas is bubbled through the cotton swab with the water which would equal Hydrochloric acid (HCl) because so little voltage is applied it is a weak dilute acid, but still strong enough to eat the steel a little to make etching in the steel. which would come out to equal ferric chloride.
there is no solution at the negative end. so there is no hydrogen production... (sodium reacts with the water to form hydrogen)
I cant believe i never thought of this! good find!
but anyway youre welcome for the info :D
Sodium reacts with water to produce Hydrogen and NaOH.
Chlorine reacts with (and is also very soluble in) water to produce oxygen, chloride ions and weak solutions of HCl.
NaOH and HCl react to form... NaCl and H2O, so completing this particular circle of life.
The 'lectricity is all that parts the NaCl into Na and Cl in the first place, and once spent, it quickly regains electronic equilibrium by reacting again.