Not very many years ago, the variety of soap molds was pretty dismal. Soapmakers made do with molds intended for gelatin desserts and candles. They improvised with cardboard boxes, plastic storage ware, and ice-cube trays.
Today there is an inspiring array of molds created just for soapmaking! From a clever and simple slab mold to the most delicate fancy design, the variety and quality has increased exponentially.
Creating Your Own Molds
Your first batches of soap will very probably be poured into “found” molds. Shoeboxes lined with plastic bags, baby-wipe containers, inexpensive plastic storage containers, and more have all been pressed into service as soap molds. You can use tubes from paper towels or toilet paper rolls. Empty plastic wrap and aluminum foil boxes make small, lidded molds. Beginning soapmakers do not need the latest advance in soap-mold technology. Your mold needs and desires will grow as you gain experience.
If you're using something plastic for a mold, such as a baby-wipe container, be sure to test it for heat resistance. Because of the high temperatures involved in soapmaking, you need plastics that will not collapse when exposed to hot soap. The easiest way to check a mold for heat safety is to place it in the sink and fill it with boiling water. If it melts, it is obviously not going to be useful. If it warps and distorts, it is not a good choice either.
You can find both simple and elaborate molds online and from specialty soap suppliers. You can spend a lot or a little. Using simple household items can save you a lot of money when it comes to choosing molds for soaping. Be creative, as this is one of the areas in which you can save some cash!
Instead of improvising your own mold, you might decide sooner rather than later to purchase a mold. You can buy single-bar molds in just about any design you can imagine. Some manufacturers make them in trays of three, four, or more. Others make single-cavity molds. Your best bet is to look in a large craft store or an online soap mold supplier.
Molds that are made especially for soapmaking will have information regarding the method of soapmaking — cold-process, hot-process, hand-milled, etc. — for which they are best suited. If you have questions, ask your supplier. Always test a new mold for heat-resistance before using for the first time. Pouring time is too late. When in doubt of the suitability of a potential mold, skip it and go for the sure thing.
You may need some additional supplies to make it easier to get your soap out of its molds. Soapmakers struggle with unmolding all the time. A simple way to ensure ease of release is to line the bottom and sides of the mold. You could brush vegetable oil lightly on the inside of the mold. Then cut plastic sheeting, freezer paper, overhead projector transparency, or other similar materials to size and press onto the oiled surface. Smooth out bumps and creases in the liner to ensure smooth surfaces on your soap.
When the soap is ready to unmold, if all has gone as it should, all you'll have to do is turn the mold over, and the beautiful soap will just plop out onto the table. Remove the liner and clean it up for reuse.
You can make a basic mold from a cardboard box lined with a plastic garbage bag. To be sure the box will hold the soap batch, measure an equivalent amount of water and pour it into the lined mold. If it doesn't fit, keep testing until you get just the size box you want.
One type of mold is a box mold. You can make your own box molds like generous and talented soapmaker Jennifer Patella of Crabapple Soap-works, who is also a talented carpenter. Her design for a simple-to-make and extraordinarily useful box mold is provided. It even has a lid! She has also contributed plans for a planer that will give even the bumpiest hot-process soap a finished look.
Making Polymer Clay Molds
You can make your own small molds for casting soap using flexible polymer clay. This type of mold-making is best-suited for small soaps to either use as-is or as embeds. You make an impression of an object you'd like to replicate as a soap, bake the clay, then use the still-flexible form as a mold. It will become brittle over time, but it is a wonderful way to make something utterly, uniquely, yours.
Help! My soap won't come out of the mold. What can I do?
If after a few days the soap won't release from the mold, put it in the freezer for half an hour and try again. If you've repeatedly frozen the soap and it still won't come out, just pry it out and form it into a soap ball.
There is a kind of polymer clay that is specifically made to be used in mold-making, so be sure to get the right thing. “Regular” polymer clay bakes hard and will not flex.
Choose a small object that is wider at the bottom than it is at the top so that the hardened soap will come out easily. You can achieve quite a lot of detail with this medium, so it works beautifully with shells, pendants, small statues, and even rubber stamps.
Follow these simple instructions:
Work the flexible polymer clay with your hands to make it pliable.
Make a tablet shape — flat on the bottom and on the top with a large enough surface area for the design and deep enough to take the full impression.
Lightly spritz the surface of the object with water and wipe off drips. The fine coating of water will help release the object from the clay.
Push the object into the clay and remove it quickly. If the impression is good, use it. If the impression is unclear, re-form the tablet and try again.
Bake the flexible mold clay as directed on the package. Generally, the temperature is 275°F and the time is ten minutes per quarter inch of thickness.
When the clay is baked, remove to a heatproof surface to cool.
Keep in mind that the clay will get softer and warmer the more you work it with your hands, so let it cool between shapings for better results. You can use one tablet for a few small impressions if you like. When using multiple items on one tablet, be sure to allow room for the clay to move and spread between images without distortion.
You can use your new mold as soon as it is cool. Be sure to store it in a dry place where it won't be exposed to light or heat. It will decay over time, but with gentle use you should be able to use it over and over.