Or.. a good demonstration of why throwing a radio into the bathtub will kill you. I'll explain later.

Speaking of killing you, as we are using water and electricity here, please be supper-duper cautious. I can't be held responsible for burned fingers, house fires, dead cats or any combination thereof. Please use some common sense!

This is a decent project that should cost you little or no money, depending on what you have laying around the house. The idea is to use electricity and salt water to etch an image into the top of an altoids tin. The same process can be used to actually cut the image all the way through if allowed to go long enough. I'll explain the principles behind this as we go along.

First things first, Project materials and cost:

1 Altoids can, or similar metal canister - $0 (I'm using garbage here...)

1 spare DC power supply brick. 5v or greater. Preferably a decent amperage. I use a 12v 1A supply. it really seems to make no difference beyond how long the etch will take - $0

Old PC case fan, light bulb.. something that will run on the current from the power supply. This is used to limit the amount of current being transmitted, as you don't want to burn out the power supply. - 0$

1 PLASTIC bowl or pan. Never NEVER use a metal pan of any kind. - 0$

About half a cup of salt. - 0$

A couple of bolts and some heavy copper wire - optional 0$

Plastic packing tape (I use clear.. don't have to I suppose.). Not masking tape. It has to stand up to salt water - 0$ I steal mine from my day job.

Sandpaper, or green scrubby. -0$ I used the scrubby from my kitchen sink. Don't tell the girlfriend.

Razor blade or knife. I highly recommend an Exact-o or similar, although I did this with a straight "utility" style blade.
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NickH8 years ago
There's a faster method of etching a design on metal using an acid solution. You need fewer parts and no electricity. Melt some old candles in a double boiler. Dip your metal piece and make sure that it's entirely covered in wax. Let it cool. Using any kind of stylus -- a toothpick will do -- draw your design by just scratching the wax away. Dunk your piece in a low acid solution. The acid will etch the metal only where the wax has been removed. Use a chicken feather or something similar to stir away air bubbles that will form on your design as the etching proceeds. Obviously, the acid solution should be placed in a glass bowl or soup plate. When finished, melt the wax away by heating your piece either by boiling it in water or with a hair dryer. CAUTION: When diluting acid, add acid to water. Never add water to acid. To avoid serious burns, use rubber gloves and goggles when dealing with acids.
char6708 NickH23 days ago

what will work as a low acid solution

Daax NickH7 years ago
I'm totally gonna do that! One question: If I use some thing like contact sheet (like a sheet of tape) instead of wax, will it work just as good? Or will the acid eat through the tape?
Zephryllis Daax7 years ago
Contact paper does work, at least I've used it for etching copper plates for printmaking. One thing to be careful of though, is that since the contact paper is thicker and gooey-er, be sure to not leave any plastic burrs (tiny edge pieces that may be sticking up from being scratched/cut away) because they will effect the etch. Also, depending on the brand, it's HARD to get all the goo off.
NickH Daax7 years ago
I have no idea. Try it on a scrap piece and see what happens.
bgugi NickH7 years ago
always do things as you ougt to (outta), add the acid to the water (watta) if you think your life's too placid, add the water to the acid...
lemon juice?? buy one of those little green bottles of pure lemon juice (no water.)
HOMEPIE64 NickH7 years ago
what do you mean by a low acid? i know that your comment is old but that never stops the press right.
NickH HOMEPIE647 years ago
A low acid solution would be a few drops of muriatic acid in a cup of water. If that works too slowly, you can add more muriatic acid. Muriatic acid is used for etching concrete to remove mold. Home Depot should carry it.
carbon NickH7 years ago
Actually, I've always seen the product you describe as being a mix, with phosphoric acid as the main ingredient. I've scoped it out at several stores, and it appears that they only carry muriatic acid in the garden section. Two one-gallon bottles (~30% concentration) for $9.98.
HOMEPIE64 NickH7 years ago
got it thanks for helping the newbee
tydeus NickH7 years ago
If you're using muriatic acid (containing HCL) you can neutralize it by carefully adding some limestone rocks. You probably have some white rocks in your neighborhood that are just a little grainy and shiny and white, those are probably the same I use from my landscaping. Don't expect to get the rock back after, it will be completely gone.
brianf25 NickH8 years ago
[Quote: Use a chicken feather or something similar to stir away air bubbles] lol.. a chicken feather
photozz (author)  NickH8 years ago
Cool idea with the wax. that would work here as well. I was trying to get away without buying anything. :) I do have cats as well. Judging by the spray pattern of salt water on my kitchen when they tried to "help", I'm reeeeealy glad I was not using acid.
Boss_Sauce8 years ago
Thanks for this tutorial! I want to etch everything now...

I did a little experimenting last night--

Curious if anybody has figured out a good inky marker that can be used to mask but will clean off with goof off or something...?
I will now reveal to you the greatest sharpie secret. The best way to remove sharpie with more sharpie ink. Wait wait let me explain. Write somthing on metal with a sharpie then write over it again and quickly wipe away. Tada, it all wipes off. Inside the pen is the chemical that disolves sharpie ink and it dries quickly. When the solvent dries up all thats left behind is your "permanent" writting.
Yeah, cause Sharpies are an alcohol based ink, so of course the sharpie will take it off. So will regular rubbing alcohol.
kool ty
You could try an oil based "Paint Pen" which should clean up nicely with a petrol based solvent (lacquer thinner).

At work I use pure alcohol (they call it E-200, not sure why... 200 proof ethanol?) to remove sharpie marks from aluminum, usually works pretty good but results can vary.
I think you could use liquid frisket (goes on with a brush or a nib.) I use it for masking glass etching, I don't see why it wouldn't work for this.
photozz (author)  Boss_Sauce8 years ago
Cool. Nice job.. I have the fan in the system cause it limits the current somewhat. On my original try, I burned out the first 1a supply I had. It just got too hot. Adding the fan just puts some limit in the circuit. Besides, it's really cool to see the fan turn on and off when you tale the metal out of the water. Sharpie seems to work pretty well. others have said nail polish ..
zus8 years ago
What metals can you do this on ? I'm guessing pretty much everything except steel ? any kind of soft metal ?
petmjohn zus2 years ago
It works on steel and stainless steel. Take a look at this instructable:
AznPanda zus6 years ago
Altoids cans work im guessin
photozz (author)  zus8 years ago
as far as I know, any metal that will conduct electricity. It's not an acidic reaction, it's electrons taking molecules of the metal away as the electricity flows out. it should work on anything including stainless.
Gonazar photozz6 years ago
I think copper is ideal isn't it? it makes a better oxidizing agent in the electrolytic cell. I just finished my chemistry 12 course, so i'm kinda testing the water in applying it in real world.
pdenise3 years ago
Did this with a single 9v battery, and it worked quickly. The battery seemed a bit warm, so next time, I'll try a small load, like a small varistor, or resistor. Great instructable!
oub3 years ago
This is the coolest presentation. Thank you so much for this. Thank you mostly for responding to the comments! Every question I had was answered. Oh... and thank you for the sense of humor.
tallpaul1003 years ago
I've always used the aerosol deodorants to remove marker pen on any wipeable surface. I've never tried with the the actual sharpie brand pens but its worked for all the others I've used. just spray it on and wipe it off! easy as pie. I've even used it to get marker pen of cd's so i can re-label em.
Hadokendude6 years ago
I had three questions: A) What do you use for a DC power supply? Like a computer power supply, or something different? B) In place of a power supply would a 9-volt battery work? and finally B) Is it imperative that I use a cooking bowl of some sort, or could a plastic disposable bowl work as well?
I once made a metal plater for jewelry with a 6/12 battery charger and a kitchen door spring and it worked like a charm....for the DC power.
photozz (author)  Hadokendude6 years ago
A: Anything that puts out DC voltage. I have used PC power supplies and "Wall Wart" adapters. both work fine. B: Yes. A battery should work ok as long as the piece is not too large. The bigger the etch, the more power or time required. A few people have used batteries with good result. C: any plastic, non-metallic container would be good. Cheerio!
aridese7 years ago
Electrolysis (etching) with table salt is an EXTREMELY DANGEROUS thing to do.

Table salt (sodium chloride) ionizes in water:
NaCl -> (Na+) + (Cl-)

The positive and negative electrodes gather Cl- and Na+ respectively. The positive electrode will make chlorine gas! I am confident you smelled a "pool" like odor when you performed this.

If you don't want to take my word for it, here is a site describing the process in greater detail:

In the quantities you are using, the amount of gas produced can be dangerous -- this is the same poison gas used in WWII. An alternative electrolyte you can try for electrolysis is sodium carbonate (washing soda) or sodium bicarbonate (baking soda) heated to 200C to produce sodium carbonate.

For the safety of others, please amend / remove this instructable...
Hahaha that website shows that the process requires molten NaCl not NaCl(aq). Hardly the same
If table salt ionizes in water... why doesn't the ocean create chlorine gas? Should I stop going to the beach? And, couldn't you just do this outside?
has to have electricity.
pharoah aridese6 years ago
First, let me point out that Chlorine gas was only used at the beginning of World War ONE, it was replaced with more effective gases such as mustard gas. Second, if you perform this experiment in a well ventilated area you should be fine. I don't think anyone here would be stupid enough to stick their face above the etch bowl and inhale for a few minutes. Just exercise a bit of caution people.
Aridese- Etching with saltwater is safe, ask someone who knows, like a teacher or art or chemistry. Better still, experience the hazard first hand: etch something. Then you can compare and contrast the sheer hazard vs. running with scissors (the pointy ones, especially) and using household ammonia cleaners (DEADLY GAS!!!!). Chlorine was used in WWI (notably at Ypres, Belgium in April 1915), but was considered more trouble than it was worth. That made it easy to get signatories to the 1925 Geneva protocols that banned the use of "poison gas".
photozz (author)  aridese7 years ago
**sigh... let's calm down here. this process may produce minute amounts of chlorine gas, but as has been discussed in the past the amount produced with a tabletop setup is to small to be noticed, much less approach dangerous levels. The level of chlorine gas coming off a swimming pool is many times more dense than what I can produce with 5volts in a mixing bowl of salt water. This has already been extensively covered farther down in the thread. No, the kitchen did not smell like a pool, and I had one etch running for over 6 hours. That being said, if you notice noxious green smoke or such, a certain amount of common sense should be applied as with any project on instruct ables.
AnotherMan5 years ago
What kinds of power supplies would you reccomend? Pc? Car battery?
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