Welcome to the wonderful world of egg etching! This super fun scientific technique is perfect for making non-traditional Easter eggs by allowing you to create, patterns, tones/shades, and surface textures without the use of dyes. BONUS: The Easter Bunny will give you extra chocolate because you have the coolest eggs on the block.

Step 1: How It Works

The shell of a chicken egg is made up of primarily calcium carbonate. If you soak this egg shell in vinegar (which is about 3% acetic acid), you start a chemical reaction that dissolves the calcium carbonate shell. The acetic acid reacts with the calcium carbonate in the egg shell and releases carbon dioxide gas that is visible as bubbles on the shell.

Any area of the shell that is 'masked' (coated or covered) so that no vinegar touches it, will not dissolve. We are going to take advantage of that bit of science to create tonal patterns on the surface of the eggs using a few different masking techniques.

NOTE: Even though the soaking time is minimal for this project, some vinegar will sneak through the shell into the egg itself, so just be aware of this if you attempt to boil and eat these once you're done.

Let's get to patterning!

Step 2: Creating Tonal Patterns

Doing multiple, short vinegar baths with masking of different areas after each bath, allows you to create some pretty cool multi-shaded patterns without using dyes!

Brown eggs will create bold, high contrast patterns, with a lot of room for tonal/shade steps in between the original brown of the shell and the almost white inner shell layer that we'll uncover through the 'etching' (aka dissolving) process. (pictured above)

Blue eggs will produce more subtle, less contrasting patterns, and are not recommended for any attempts at tonal steps.

White eggs can work if you etch deeply enough for shadow play to occur OR if you dye the eggs first and then mask your pattern. Lots of room to play around on your own with this technique! (Not demonstrated in this instructable. Just freestyle!)

Step 3: Supplies

raw* rainbow eggs (brown and blue)
white vinegar*
masking tools:
- rubber bands
- thin masking tape
- small scissors
- medium or heavy tip kistka wax writing tool
- tea light candle
glass 8oz cups
plastic pot cleaning scrubby
old toothbrush
small sponge
soup spoon

*I used raw eggs because hard boiling them dulls the color of the shell a bit. I plan to blow the yolks out later to preserve my designs. (The how-to for that is not included in this instructable, so just use your favorite yolk removal method or check with Google.)

Step 4: Masking Technique #1: Thin Masking Tape

Use the thin masking tape to create a pattern on the surface of your egg.

Follow my example in the photos above OR come up with your own!

Be sure the tape is pressed firmly onto the surface of the egg by running your fingertips over all the edges and tape ends.

NOTE: This technique is best used for a maximum of two etching baths (= two shade tones) as the tape will begin to shrivel a bit and lift up if it's submerged too many times.

Step 5: Masking Technique #2: Rubber Bands

This one is the easiest and most straight forward technique. Wrap rubber bands around the egg in any way/pattern you'd like! You can try doing multiple baths/dips, but just remember that as you layer the rubber bands, the will be further away from the surface giving you softer, less defined lines, which would be even less so in a lighter shade.

Step 6: Masking Technique #3: Wax

Using a kistka tool (from Ukrainian egg making), you can draw fairly controlled lines in wax, making the pattern options endless!! And because there's no chance of the wax moving on you or falling off like the rubber bands and tape, you can do many short vinegar baths to create lots of shades/tones. (Remember brown eggs are best for this!)

I didn't get too fancy with shading on this egg, I just went for two shades/baths, but the lines were so thin that it almost wasn't worth it. I'd suggest bolder lines/shapes for more effective shading.

One method is to sketch a pattern on the shell in pencil first, so there are lines to follow with the wax. But don't be afraid to skip the pencil and go rogue!

NOTE: I used a rubber band to help me draw straight(ish) pencil lines for my pattern. (see photos above)

Step 7: Wax Part II

When you're ready to draw with the kistka, light the candle and scrape some wax from the edge of the tea light into the reservoir of the kistka. (like pictured)

Heat the metal tip of the tool over the flame. You'll know you've heated it enough when the wax flows easily if you test draw on a piece of paper.

Once you've achieved optimum melty-ness, start tracing your pencil lines with the wax. Keep re-heating the kistka and drawing until you've traced over all the lines that you want dark brown.

Step 8: It's Bath Time!

Fill 2-3 small containers 3/4 of the way with vinegar. It's best if the eggs don't touch each other during the etching process (otherwise they will mask each other wherever they are touching) which is why I like to give them each their own container. I use glass so I can watch the process (=fun) but it's not necessary. Any container will do.

Place the eggs in the vinegar and set your timer for 3-4 minutes.

Step 9: Science Is Magic

Be sure to check out the bubbles that the reaction creates!

Step 10: Bath Time's Over (for Now)

Take the eggs out of their baths one by one, and running them under water in the sink or placing them in a small bowl of water, carefully wipe off the unmasked surfaces with a sponge or old toothbrush. This will remove the first dissolved layer of shell (and color) leaving a new, lighter shade surface.

With the rubber band and tape ones, try not to move or disturb the masking.

Step 11: Creating Tones/Shades

This is the point that you add more masking if you want to create some lighter shaded areas.

I did a few more lines on my wax egg. They were a bit thin to really see the difference in shades between the original and lighter brown, so I would suggest using thicker lines or shapes to really make it effective.

NOTE: Even if you don't want more than one shade, you still want to do 2-3 baths, removing the dissolved shell in between each, to get really nice, deep etching.

Step 12: Second Bath Time!

Place your eggs back into the vinegar baths for another 2-3 minutes.*

*Feel free to play with the length of each bath time. It takes 48 hours in vinegar to go all the way through the shell to the inner membrane, so don't worry about that happening with these short term vinegar 'swims'.

Step 13: Remove and Wipe

Once again, remove the eggs from the baths and wipe off the dissolved shell.

Step 14: Removing the Masks

There are several methods to removing wax from eggs, but my favorite is to heat water in a kettle to ALMOST boiling and pour it over the egg in a bowl. The wax will melt and float to the surface of the water. Place a paper towel on the surface of the water and carefully (it's hot!) pull the towel off. This removes the floating wax debris and keeps it from re-sticking to the egg when you remove it from the water.

If there are any lingering bits of wax, run the egg under hot tap water and gently scrub the surface with a plastic pot scrubber until it's clean.

For the taped eggs, gently remove your designs.

Step 15: Enjoy the Pretty!

The pattern possibilities are endless! So have fun with this.

A Reminder: I plan on blowing the yolks out later to preserve my designs. The how-to for this is not included in this instructable, so just use your favorite yolk removal method or ask Google!

Happy Easter y'all!