How to Etch a Candy Tin with Saltwater and Electricity
Re-use old candy packaging to make practical art: a recycyling craft.
Many types of candy and lozenges come in tins. While they are an awfully great way to carry the mints or other hard candies around it's an awful waste to throw them out when the contents have been consumed.
But the good news is that you can re-use these handy containers to store things in or to assemble small kits of useful items. You can make up a tiny first aid kit in a candy tin or use one to store needles and thread. Empty mint tins have lots of uses!
I prefer such things be a bit more decorative or at least more interesting and I find I need a way to distinguish tins put to a new use from the ones with mints still in them. It's good to have some way to tell all of them apart and to distinguish them from the ones that still have sweets inside, so my solution is to decorate my old candy tins by etching images or designs into them.
This lens will give you step-by-step instructions on how to etch an image or design using saltwater and electricity. It's kind of like a craft and a science project combined.
Materials, Tools, and Supplies for this Etching Project
- One 6V dry cell battery
- Coarse grit sandpaper
- Fine grit sandpaper
- One metal candy tin
- Dust mask
- Eye protection
- Insulated copper wire
- Wire cutters and stripper
- A ballpoint pen or pencil
- A large glass or plastic bowl
Choosing a Good Container
Choosing the Right Tin for the Project
A good candy tin for this project will be smooth rather than embossed and will have enough room on the front to draw the design or image of your choice. I like to use the packages that Newman's Own and Penguin mints come in as they are free from embossing or other raised designs, but any smooth tin will work just as well.
Altoids boxes used to work great because they were smooth, but the new ones are embossed. This old, smooth Altoids tin was a fortunate find from under my sink.
Be sure to wear eye protection and a dust mask while working on this project!
Step One: Sand Off the Paint
Use the Coarse Sandpaper First
Starting with the coarsest sandpaper, sand off all the paint on the surfaces you will be using. The paint can be left on the sides and back of the tin if desired.
Sand in a single direction to more easily achieve a smooth finish. It will take less work to sand out the scratches from the coarse sandpaper with the fine sandpaper if you do.
Step Two: Sand the Surface Smooth
Polish It Smooth With Fine Grit Sandpaper
Use a fine grit sandpaper to smooth the rough surface of the rough-sanded tin. Again, pick a direction and sand in it to avoid a grooving or crosshatching effect.
A Blank Slate
Once you've sanded the surfaces to the desired smoothness your tin is ready to begin the crayon wax masking process.
Step Three: Cover It with Crayon
Scribble Wax Onto the Tin
Use a dark colored crayon to color in the side you wish to create a design on. Any color will do because you are just going to rub it off later, but dark colors provide the best contrast so you can see what you are doing when you scratch an image into it.
Step Four: Melt the Crayon with a Hair Dryer
Melt the Wax Crayon
Once you've solidly colored in the side you wish to use, heat it with a hairdryer on high until it begins to melt. While the metal is still hot, fill in any thin spots of wax using your crayon. You don't need to get perfect coverage but keep in mind that all uncovered parts will get etched.
Undisturbed areas of this wax covering will seal the saltwater solution away from the surface of the tin except in the areas you choose to scratch it away. That's how you'll end up with a picture or design of your choosing instead of just a pitted-looking old tin.
Step Five: Use a Pencil to Scratch in an Image
Draw the Image of Your Choosing By Scratching Away Wax
Use a pencil or ball-point pen to scratch out a design or picture. Don't try to scratch into the metal, just scratch through the wax. I like trilobites so I scratched one into the wax this time. You can also lay a drawing or printed image over top and trace it, pressing hard, if you don't feel confident drawing something freehand.
Simple line drawings work best for this project.
Step Six: Hook the Wires to the Battery
Prepare and Attach the Wires
Cut the wires about a foot long, strip about an inch and a half (about three centimeters) of each end on each wire. Test the wires to see how you need to bend them to stay on the battery's contacts without allowing their stripped ends to touch each other or the other contact.
Step Seven: Put the First Wire Into the Salt Water Bath
Mix Up the Salt and Water Bath and Lay the Positive Wire in It
Mix table salt into a glass or plastic bowl of warm water until you can dissolve no more in it. Remove the negative terminal's wire, leaving the positive terminal's wire attached. Lay the positive wire's end in the saltwater bath.
Step Eight: Attach the Second Wire to the Battery and Submerge the Tin
Give Your Tin a Shocking Bath
Set one stripped end of the negative wire into the saltwater bath. Then set the tin into saltwater bath so the side to be etched is in the water above the negative wire end and touching it. Then attach the negative wire to the negative battery terminal. This will make a stream of bubbles come up from the wire's tip under the tin. This is normal and desired.
The gas made is hydrogen which is flammable so perform this part of the project away from open flame and in a well ventilated area.
Allow the tin to sit there over the bubbling negative wire for five to ten minutes then remove the negative wire from the battery.
Step Ten: Remove It from the Bath and Dry It Off
Dry It and Rub Off the Wax Crayon Mask
Remove the tin from the saltwater bath and dry it off. Then scrub off the crayon wax with a washcloth and polish it with the fine-grit sandpaper. Wash it gently with warm water to remove any metal dust and dry it gently with a towel.
The Finished Etching
Put on a Coat or Don't. It Looks Cool Either Way.
You can now either coat the tin with a clear varnish or allow the natural patina of oxidation to age and enhance your etching.
Do You Re-Use Food or Product Packaging?
Do you re-use any of the durable packaging your food or household products come in?
Whether it's using margarine tubs to store leftovers, jars to store paperclips, or candy tins to make art and storage, it all helps to keep these things out of landfills. Re-using product packaging also helps the environment in other ways - it saves you from buying something else to serve the same purpose, something which would have to be manufactured from raw materials and brought to you using more fossil fuel.