Ingredients
- 2 cups baking soda, fresh and finely powdered
- 1/2 cup warm water, plus up to 2 tablespoons more if needed
- 1 tablespoon white craft glue, such as Elmer's, optional for extra firmness
- 1 small bowl, 2-cup capacity
- 1 measuring cup, 1-cup size
- 1 tablespoon measuring spoon
- 1 silicone spatula or sturdy spoon, 8 to 10 inches long
- 1 shallow tray, about 8 inches by 10 inches
- 1 sheet parchment paper, about 12 inches by 16 inches
- 1 small smooth stone, shell, or crumpled piece of aluminum foil, about 2 to 3 inches wide, for the interior form
- 1 pair nitrile or household gloves, medium or large size
- 1 disposable dust mask, for sanding
- 1 sheet 120 grit sandpaper, about 3 inches by 8 inches
- 1 sheet 220 grit sandpaper, about 3 inches by 8 inches
- 1 small paintbrush, 1/2 inch wide, for brushing away loose powder
- 1 small bottle water-based clear craft sealer, 2 fluid ounces
- 1 drop cloth or old cotton towel, at least 24 inches square
- 1 small piece of painter's tape, about 6 inches long, optional for holding parchment flat
Instructions
- Cover your table with the drop cloth and parchment.
- Set the smooth stone, shell, or foil form on the parchment-lined tray.
- Measure 2 cups of baking soda into the bowl.
- Add 1/2 cup warm water and stir slowly for about 2 minutes.
- Mix in 1 tablespoon white craft glue if you want a firmer piece.
- Check the texture with a gloved fingertip.
- Press the paste around the form in small handfuls, building the shape to roughly 3 inches wide and 1 1/2 inches tall.
- Use the spoon tip to create two or three shallow grooves from the top toward the sides.
- Let the piece sit uncovered on the tray for 6 hours.
- Carefully turn it, remove the form, and let it dry for another 18 to 42 hours.
- When the surface feels hard, brush away loose powder.
- Sand only the sharpest edges with 120 grit sandpaper, then one gentle pass with 220 grit.
- Apply a very thin coat of water-based clear sealer with the brush.
- Let it dry for 2 hours, then add another coat if needed.
- Allow the finished crystal to cure for 24 hours before moving it.
Notes
This project may involve some trial and error, and small cracks or unevenness can be part of its charm.
- Cook Time: 40 minutes
