Layered soaps allow you to build a thing of beauty—or a thing of wackiness—one color at a time.
Step 1: Cut base into cubes Cut your base into 1-inch cubes to allow for easier melting. You can estimate the amount to melt by seeing how many chunks fit into each mold. In general, a pound of soap base should make about 3 medium-sized bars of soap, or numerous smaller ones.
Step 2: Heat soap base Place your soap base into the glass bowl or measuring cup, cover the top with plastic wrap, and heat it in the microwave on high for 30 seconds. If the base isn't completely melted, remove it, stir it with a whisk, and re-heat it at 10-second intervals, stirring in between, until it is. Don't forget to replace the plastic wrap each time.
Step 3: Stir gently Remove the melted base from the microwave and stir it gently, to avoid creating air bubbles.
Step 4: Pour into bowls Separate the soap base by pouring it into as many bowls as colors you plan to use.
TIP: For the best results, plan out the pattern you'd like to make ahead of time: whether it's a rainbow of colorful stripes or just alternating bands of two or three colors, or anything in between.
Step 5: Add dyes Add the dyes or colorants to each of the separate bowls and stir.
TIP: Be sure to use only soap-safe dyes and follow any special instructions on the package.
Step 6: Pour first layer Pour the first layer into your mold.
TIP: You can use a loaf mold to make multiple bars that will all have more or less the same pattern, or multiple single molds to create unique patterns.
Step 7: Spray with alcohol Spray the layer you've already poured into the mold with rubbing alcohol to eliminate air bubbles and help the layers adhere. Let it cool until a "skin" has formed.
TIP: If the colored bases are starting to cool and harden, pop them in the microwave on high for 10 to 15 seconds until they've re-melted.
Step 8: Continue layering Slowly pour another colored layer over the first layer. Spritz it with rubbing alcohol and let it cool, allowing a skin to form over the top. Continue in this way until you've added all your colors in as many layers as you like.
Step 9: Let cool Let your creation cool for several hours or overnight, pop it out of its mold in the morning, and you're ready to bathe in ribbons of color.
FACT: Clay cylinders containing fat boiled with ashes were found during an excavation of ancient Babylon--suggesting that soap making could have started as early as 2,800 B.C.