This is my favorite technique for swirling melt and pour soap because it doesn’t have a lot of steps, but it makes a very fancy looking bar of soap.
I am going to give a general explanation of my method, rather than precise measurements, because there are a few variables.
For this you will need a loaf mold of any size. You can use an actual soap mold, or even a silicone bread loaf pan.
You also need melt and pour soap base, one or two non-bleeding colors, fragrance (if desired), and basic melt and pour soap making equipment (dishes, spoons, alcohol spray bottle, etc.).
You are going to make the first layer fill your mold about 3/4 of the way. The way I determine how much soap I need is to fill the mold to the desired level with water and measure that. Since I melt my soap base in a glass measuring cup anyway, it’s an easy way to figure out how much soap I will need. (When you are finished you can always weigh the soap for future reference.)
Cut up the soap into small chunks, filling the measuring cup over the desired level. (You will have a smaller volume once it melts.) Microwave in 30-second intervals, stirring in between. As the soap melts, if you can tell that you will need more, add more until you reach the level you need in the measuring cup.
Once your soap is melted, add your base color (the white in the soap above) and fragrance. Pour into the mold and spritz with alcohol. Allow this layer to set until a thin skin starts to form on the cooled soap.
While the soap is cooling, prepare the next layer. Melt the soap and add your fragrance and contrasting color. You want this layer to still be hot when you pour it, so it breaks through the skin of the first layer.
Color being added to melted clear soap
Here is where you can get creative. Spray the first layer with alcohol. Then, pour the hot melted soap from a few inches (or more) above the loaf. You can pour in a straight line down the middle, or swirl in an S-shaped motion as you go. If you want, you can gently swirl with a bamboo skewer to add more effects. Just don’t overdo it or you will have just one solid color. Less is more! I suggest you try it the first time with only a straight pour (no skewer) to see how it looks before you play around.
When you finish pouring, spray with a final spritz of alcohol to remove all air bubbles on the surface. Allow the loaf to set until fully cooled and hardened.
The pattern on the top is cool, but you cannot see the swirl pattern until you unmold and cut your bars.
For this loaf I used a skewer only on one end. You can see that some bars have a simpler swirl pattern.
Play around with this simple technique and make it your own. Do different pours, experiment with skewers and other swirling objects, or even change the ratio of the two soaps. (Or use more than two!) It is an easy way to get spectacular bars of swirled soap.