We are excited to bring you recipes from our favorite creators. Here Brittany Boles of Seaspell fiber shares with us her tutorial on making white chalk with eggshells. If you try it, let us know and tag us @botanicalcolors & @seaspellfiber.

Materials

• One dozen eggshells 
• An oven
• Baking tray
• Spoon
• Coffee grinder 
• Fine mesh sieve – 160-200 mesh size for very fine powder
• Respirator mask
• Large piece of paper 

Skill Level

Beginner

PREP & COOK TIME

45 min -1hr

This recipe is for a beginner looking to make their own natural art materials. This is for adults only as you will be working with heat. Little fingers can use the chalk once made.

Eggshell White Chalk

The egg has long been a symbol of fertility & creation which begs us the eternal question, “which came first, charcoal or chalk?” One mythos tells that the god of sun & fire, Ra, was hatched from a cosmic egg. I am personally team “chalk came first”, but it may be due to my own preference in starting with white pastel highlights first on paper, before adding color. Eggshell is composed of 94% calcium carbonate aka chalk and is created in the avian shell gland. The process is called calcification and takes about 20 hrs as layers of calcium carbonate are added to form the shell.  All parts of the egg have a long history of use in both paper and fiber art: egg yolk binder in tempera, gesso canvas preparation, modifier/post-mordant bath in natural fiber dyeing, and chalk pastels, to name a few.

In my journey of connecting with source materials, the motivation to experiment with eggshells for homemade chalk began with handcrafting soft pastels. I like to save up shells through-out the week until I have a big batch to bake, grind, and sift. 

Does eggshell color impact the chalk?

White eggshells will produce a traditional eggshell white, while brown eggs add a very subtle touch of beige(see image). Trial with other egg colors and let us know your results by tagging us on instagram @seaspellfiber + @botanicalcolors

Make your own eggshell chalk

1. Rinse the eggshells thoroughly and place on a baking tray in the oven at 275° F for approximately 15 mins or until eggshells are bone dry. After baking, if any of the thin, papery inner membranes are still intact on the inside of the eggshell, remove them gently with a spoon to be discarded/composted.
2. With a respirator mask on, break shells into smaller pieces by hand and place in a dedicated coffee grinder. Pulse in small batches for several minutes until a coarse powder-like consistency. 
3. Utilizing a fine mesh sieve (mesh size 160-200 is better for a extra fine powder consistency) sift the fine powder onto a large piece of paper(add a crease down the middle) for easy transferring.. *mask should still be on*. Any larger pieces left behind in the sieve are adequate for sidewalk chalk quality or can be fed to your chickens, added to your worm bin, composted, or placed in the garden to boost calcium content in the soil(ie. your madder plants will love it!)
4. Your eggshell chalk powder is now ready for use: mix with your favorite binder for sidewalk chalk, pastel, or paint-making or transfer via the creased paper into a container for infinite storage. 

Just the Egg-sentials:

• If your powder has large chunks or you hear scraping against the paper, utilize a smaller size mesh sieve. 160 -200 mesh size is considered adequate for extra fine powder which is better for pastels, while coarse powder can work just fine for sidewalk-grade chalk and can be sifted with a 60 mesh sieve(a common size for kitchen flour sieves). 
• A coffee grinder is by far the best tool for grinding down shells to a consistent enough powder for sifting. It can take hours/days with a mortar and pestle and a food processor will leave you with large shell chunks and a dull blade. 
• Protect your lungs and always use a respirator mask when grinding, sifting, & preparing any fine dry powders. 
• Cooking shells in the oven sterilizes the shells and helps soften them for easier grinding.
• Click here for more info on fiber art uses for chalk from Botanical Colors.