Introduction: Etched Minty Valentines Candy Box

Picture of Etched Minty Valentines Candy Box

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.

Step 1: Prep the Minty Tin

Picture of Prep the Minty Tin

For the tin to etch properly, the top of the tin will need to be cleaned to bare metal. This can be done with a fine grade of sandpaper, or a green scrubby. I tend to go with a little of both.

Run the tin under hot water and sand lightly until most of the paint is gone. then clean it up with the scrubby. any areas where there is paint remaining will not etch properly, so take your time.

When it looks clean, rinse and dry it off thoroughly. At this point, try not to touch the surface any more than you have to . The oils from your skin could affect or block the etching.

Step 2: Masking the Tin and Draw Your Design

Picture of Masking the Tin and Draw Your Design

You need to mask off the top of the tin. Cover the bare metal with the packing tape. If you use more than one strip of tape, leave a little overlap to assure that you have a water tight seal between the pieces. Any bare metal still revealed at this point could wind up being etched. Try and work out all the air bubbles and make sure the edges are covered.

Taking a sharpie or other pen that will draw on the tape, sketch out your design. it's OK to be a little sloppy. I had drawn in some writing here, but abandoned it in the next step. I'll add my "message" later. You will be cutting around the design.

Step 3: Cut Out the Design

This one can take some practice, depending on how steady your hands are. Using the razor, carefully cut out the design from the tape. In this case, I went around each side of the lines I had drawn, then using the tip of the blade, peeled the tape out of the line, leaving the bare metal exposed.

Where ever you remove the tape, the metal will be etched. Mistakes are fine. don't panic. If something gets cut by accident, just use another piece of tape to seal it up again. your just creating a mask here to keep the water off certain areas. Your cutting does not have to be a work of art. it just has to get the job done.

This step can take some time. Be patient and work slow. I abandoned the writing in my design as it was just too small and I was using the wrong blade for really delicate work.

I'll take this opportunity to point out an option. You could also draw your design on the bare cover using a sharpie or other non water based ink. The etch would then remove all material not covered by the sharpie. I prefer the mask and cut out method. It gives you much cleaner lines, and just looks nicer when done. I have examples of both methods later in the instructions.

Step 4: Set Up the Etching Station

Picture of Set Up the Etching Station

There are several important points to make here.

First, you must use a DC power supply. An AC supply will have little or no effect, no mater how strong. AC current stands for Alternating current. It means that there really is no "positive" electrode. The current in AC circuits alternates directions. The electrons will never flow consistently enough in one direction to transfer metal particles. The Mythbusters (US Discovery channel show..) actually demonstrated this theory in episode 26 "Salsa escape)
Jamie and Adam attempted to cut their way through prison bars using this method and salsa as the liquid. Adam used direct AC current from the wall, Jamie used DC from a smashed radio power supply. Adam's had no effect.. Jamie's bars were cut clean off.

Second, DO NOT plug in the power supply until everything is set up. plugging it in is the last step before etching starts.

Third. When testing the PC fan, don't accidentally put your finger in there and cut it like I did that one time.

Fourth. If you have cats, keep the cords up and tight. It will make a spectacular and dangerous mess when your cat grabs a wire and runs for it.... little sh**s...

Fifth. I should not have to say this, but I will. In no case under any circumstances at all ever should you run house (mains - for those of you overseas) current directly into the solution. it just won't work for one thing, and could very easily kill you.

Last, you are using electricity here. Please be careful.

The basic idea of using electricity to plate or etch metal has been around for a long time. In fact, it has been the subject of several articles:

There was another one where a guy used the same process to cut a design into his PC case, but I can't find it right now...

It's essentially the same principle used to chrome or gold plate metal. You put the positive electrode on one metal, and the negative electrode on another. When you submerse them in a conductive liquid, like saturated salt water, the electrons will flow from one metal to the other, taking some of the metal with them. You will get the idea.

This is also (in principle) how throwing a radio in the tub will kill you. The electricity will flow from the radio, through YOU, to the metal drain in the tub. Mythbusters episode 19:

Take the plastic bowl and fill it with about 2-3 inches of lukewarm water. Slowly dissolve the salt into the water until it won't take any more. This is a saturated salt solution. You could use regular water without the salt, but it would require more electricity, and take far longer. The salt increases the conductivity of the water greatly.

For the process to work, the two metals should be close, but not touch in the water. I usually pinch the negative wire between the lid and base of the tin, then connect the positive electrode to the fan, and then to two lengths of copper wire wrapped around some bolts. Check the diagram and picture below. The bolts just help create more surface area. You could use the wire alone. I usually use two bolts. It spreads the effect out better. If you only used one electrode, try to get it centered under the piece. If it's off to one side, the etch could be uneven.

In this case, I have the bolts on the bottom of the pan, add the tin floating upside down in the water. It works just as well to flood the tin and have it submerged in the water.

Step 5: POWER ON!

Picture of POWER ON!

OK. Once you have it all together, make sure the tin is not touching the wire/bolts in the liquid. Make sure nothing is shorted. Make sure your fingers are not in the fan. Put the cat in the closet.

Plug in the power supply. For safety - DO NOT leave the room. Sit there and watch. It should not take that long. And it's cool looking.

You should immediately notice the fan spinning, and bubbles rising from the bolts. If none of this is going on, unplug the power and check all your connections. It could be one of several things.

1. Wires crossed or wired incorrectly. The positive should be on the tin, the negative on the wire/bolts. Make sure nothing is shorting out. If the bubbles are only coming off the tin, you have it wired backwards.

2. Parts are too far apart. Try to make it less than an inch, if you can.

3. Not enough power. You might need a stronger supply.

Once you have bubbles, you will notice the water start to change colors. It can vary depending on the metals you are using. There will eventually be some scum as well. This is all normal. In the pictures, you can see mine going a bit orange.

Let it go for about 5 minutes. You can check every now and then to see how it's working. Times will vary depending on the strength of your power supply. Once it appears to be etched to your satisfaction, unplug the power, and remove the tin. Rinse it well in warm water, and remove the tape. If any adhesive is left behind, just clean it off with GOO GONE or some such solvent.

I would not recommend using the bowl for food after this. The scum left behind should be explanation enough.

Step 6: Ta-DA!

Picture of Ta-DA!

Bingo! Etched Tin. Do a little dance and go show the neighbors.

If you were to allow the etch process to continue, it could cut all the way through the metal, creating a cut-out design.

You could stop here, or you could get fancy. I got fancy.

Using another idea, I opened the tin, and wrote my message on the inside of the lid using a sharpie. Any non-water soluble pen should work, but you will need to get it off again, so don't go crazy.

I covered the top of the lid in tape again to protect it. I then etched the lid portion using the same process. The areas where the sharpie was resisted the etching (pretty well anyhow) leaving the writing behind. After it etched a bit, the cat knocked the whole damn thing over. It had worked pretty well by that point though. I rinsed it, removed the tape from the top and lightly used a green scrubby to remove the sharpie revealing the un-etched area underneath.

I took some spare fabric we had laying around and glued it to the inside. I would have preferred felt, but you work with what you have. I'm filling it with chocolates for my beautiful and fabulous girlfriend. Sorry about the bowl and scrubby dear.

Good luck, be safe and have fun!


NickH (author)2007-01-30

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 (author)NickH2015-02-09

what will work as a low acid solution

Daax (author)NickH2007-12-23

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 (author)Daax2008-02-29

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 (author)Daax2008-01-05

I have no idea. Try it on a scrap piece and see what happens.

bgugi (author)NickH2008-02-11

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 (author)NickH2007-05-01

what do you mean by a low acid? i know that your comment is old but that never stops the press right.

NickH (author)HOMEPIE642007-05-03

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 (author)NickH2007-06-17

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 (author)NickH2007-05-05

got it thanks for helping the newbee

tydeus (author)NickH2007-06-11

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 (author)NickH2007-01-31

[Quote: Use a chicken feather or something similar to stir away air bubbles] lol.. a chicken feather

photozz (author)NickH2007-01-30

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_Sauce (author)2007-02-01

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...?

Jalakahops (author)Boss_Sauce2008-05-04

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.

vxb222 (author)Jalakahops2012-06-19

Yeah, cause Sharpies are an alcohol based ink, so of course the sharpie will take it off. So will regular rubbing alcohol.

theburn7 (author)Jalakahops2008-06-13

kool ty

Linksep (author)Boss_Sauce2008-05-15

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.

spinnergrrrl (author)Boss_Sauce2007-02-03

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_Sauce2007-02-02

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 ..

zus (author)2007-01-29

What metals can you do this on ? I'm guessing pretty much everything except steel ? any kind of soft metal ?

petmjohn (author)zus2012-04-16

It works on steel and stainless steel. Take a look at this instructable:

AznPanda (author)zus2008-11-02

Altoids cans work im guessin

photozz (author)zus2007-01-29

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 (author)photozz2008-04-22

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.

pdenise (author)2012-01-13

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!

oub (author)2011-06-26

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.

tallpaul100 (author)2011-05-10

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.

Hadokendude (author)2008-12-15

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?

imajem (author)Hadokendude2010-07-11

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)Hadokendude2008-12-16

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!

aridese (author)2007-06-20

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...

mxridercc (author)aridese2010-02-03

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 (author)aridese2008-07-30

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.

offlogic (author)aridese2007-09-11

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)aridese2007-06-23

**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.

AnotherMan (author)2009-12-08

What kinds of power supplies would you reccomend? Pc? Car battery?

ward2u (author)2009-05-01

thank you it is a nice job

gnargnar (author)2008-11-18

stupid question: where do i get an AC power supply? i have one of those "pick-your-voltage" things and it say AC/DC converter but that doesn't help me much... what's the verdict on 9v battery with a lightbulb in the circuit? also, any examples of the muriatic acid edition? thanks!

AznPanda (author)2008-11-02

Yeah CAN WE USE CHEAP PLASTIC DISPOSABLE Bowls? Can we use light bulbs instead of fans?? Are you sure this works? or is there a diffrent way to do this? Willa 9 v battery work with copper wiring a completeely sand papered altoids can and a light bulb instead of a fan? Please respond....

siege engines ahoy (author)2008-09-26

In addition, can i use one of those cheap disposable plastic bowls/ trying 2 keep my bills to a minimum lol

siege engines ahoy (author)2008-09-25

Could you just use a 9v battery for this? assuming you add a shi*load more fans, i assume. . . could i just use a buncha little lights? i want to do this at school with my science teacher . . . great project btw

mistermarchman (author)2008-08-15

so, this could also work for etching circuit boards, no need for that ferric chloride. hmm. i might just have to try that.

theburn7 (author)2008-06-13

dude, if i ever have a mythbusters question, i will ask u

HOMEPIE64 (author)2008-05-04

do another instructable on how to correctly felt the inside

Bran (author)2007-10-18

This is so awesome! This makes me really want to (gasp) etch my Sandisk Sansa View (8gb) when I get it, though I will of course go through many, many test runs. Is there any way that you could etch it without dunking it in the water, as precious electronics don't mix too well with water. Thanks!

recon506 (author)Bran2008-03-29

just pop the drive open and pull the circuit board out. then etch, and when you're done dry the board less drive out with a hair-dryer and put the circuit board back.

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