How to Tattoo a Knife Blade W/ (Proper) Metal Etching




Introduction: How to Tattoo a Knife Blade W/ (Proper) Metal Etching

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Today I am showing you how to Tattoo a Chef Knife Blade, using a 9v battery and few tablespoons of salt.

The Tattoo process we are using, is called METAL ETCHING and it is extremely powerful. A chef knife blade is usually very very hard but, with just a 9v battery and some patience , we can tear it off.


First off, I am covering the blade with tape. Any tape works, as long as it is sturdy and waterproof.

If you still have the handle on your knife, which is probably the case, then leave a small part uncovered, as close as possible to the handle.

Then, with a utility knife, I am cutting out a test design,


Fill up a glass jar with water and add 2 tbsp of salt per liter.

Dip the blade in it. warning : only the design and the tape-covered-part must be submerged.

You also need a sacrificial piece of the same metal. In my case a stainless steel fork from which i scraped any varnish off.

Connect an alligator clip to a dry uncovered part of your blade, and another one to the sacrificial piece.

For the record, I bought a dozen of those clips online for just a few bucks.

Place this setup OUTSIDE, and then, using a fresh 9Volts battery, connect the BLADE to POSITIVE and the Piece to NEGATIVE.

The reason why we place it outside is SAFETY : There is a small gas emission which is not desired indoors.

You can tell it’s working when you got bubbles going on. 15 minutes are usually enough for a small design, with a brand new 9v battery.


Out of the bath, give it a quick rinse and remove all that tape. You can see, The design is now encrusted in the blade. I like how dark and rough it is.


Right, having my name on my blade is cool but... Let’s bring that to the next level. I say we tattoo the whole thing.

Again. Cover the blade with tape. Cut off your designs, and proceed with METAL ETCHING.

Quick notice : That 9v battery is not powerful enough to tattoo the whole blade in one GO. So I am doing it a small surface at a time, about 2 inches square.


I admit It took me some time, but at the end, this is what I got : A CUSTOM BLADE with my own PIRATE TATOOS on it.

So guys that’s it, I hope you enjoyed this DIY action. I would suggest for your first tattoo to do it on a test blade, that what I did, just to see how it works practically.

3 People Made This Project!


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43 Discussions

You can do a etching chemical with a industrial hydrochloric acid and industrial hydrogen peroxide in les than 30 seconds, without battery ;-)

An old mobile phone charger works well for electrolysis just take the phone plug end off and put on some crockadile clips on

You actually do not need a piece of stainless Steel for the negative pole. It is possible with nearly every piece of metal, but using stainless Materials like Stainless steel, copper or silver will lead to a higher efficiency

This is really cool! Does anyone know if you could also hook up like a battery charger or like a big car battery to etch this? That way you wouldn't have to wait very long and buy a bunch of 9v batteries.

6 replies

Technically you ould use any DC Voltage Source. The Voltage Should not be too high for security reasons (my recommendation: max. 30 V), but also not too low. Good chargers usually check wether a battery is connected, and a car Battery dies when the voltage drops below ~10V. I recommend using a transformer from an old external Hard drive or something similar.

I've done this with a car battery charger but you can get way too much current going through if the piece is large enough and it will etch way too fast and the current agitation can pull of your resist.

I now use a plug in 500w transformer that works really well.

Nice... Can someone explain how this works?

You should try this on the huge pizza cutter you made with Jimmy Diresta!

Saltwater forms chloride gas Cl2 (from NaCl), which is extremely poisonous.

Better use sodium carbonate, Na2CO3, which is available at a pharmacy

Worked but didn't etch on the kitchen ax I wanted to tattoo as a present for a friend of my. (Did got some of the coating from the ax).

Nice work. Always good to see someone achieve a good effect with (relatively) low tech :)

I was just wondering if the same technique could be used to sharpen files - usually done with an acid bath, so this would be way safer! Suppose there's only one way to find out...

1 reply

now that i have a nice etched surface how can i color it? like reversing the process with a metal that gives off a pretty color, of a dye, or gun blue, just as a thought. thanks

1 reply

reverse the polarity and use a gold sulfate, copper sulfate solution . . . google

You can use a car battery charger to replace the 9 volt battery. that way you have plenty of power.

1 reply

I should add that the car battery charger needs to be on trickle charge so you don't have too much power and melt the wires or worse start a fire!