Making a Custom Silicone Mold

I use silicone molds pretty regularly and for lots of different things. As you already know, one of my favorite soap molds is made of silicone. But I also use much smaller ones for making chocolates, candies and fondant/gumpaste decorations for cakes. I also use long flat ones for making cake lace. I’ve got a new soap fragrance that I’ve been putting off using because I have a very specific design in mind, one that will require little raspberry soap embeds made from melt & pour.  I did some poking around on Etsy, and saw a variety of raspberry molds available. I didn’t want every soap raspberry to be exactly the same. I wanted them to look unique and more like the real thing. The best way to accomplish that is to actually mold a real raspberry.

But then I got to thinking… why don’t I just make one myself? Considering how often I need specialized molds, it would be a great skill to have.

There are several different companies that make silicone molding rubber, but the one I saw the most often (and with the most good reviews!) was from Smooth-On.  Smooth-On carries a variety of products for molding, casting and sculpture. Even life-casting! For my particular application, I chose OOMOO-30, an easy to use silicone rubber compound that gives you 30 minutes of working time and cures in 6 hours.  You can purchase it from their website, but I bought a 2.8 lb. trial kit from Amazon. It was easily enough to mold 18 raspberries with a little left over.

As you’ll see in the video below, it really is quite easy to use. It comes in two parts, A and B, and you mix them together at a 1:1 ratio by volume — no scale necessary! The mixture is quite thick and a little difficult to stir. But the two parts are tinted different colors, so you’ll know they’re thoroughly mixed when there are no streaks remaining. My utensil was not quite long enough, so I had some silicone in the bottom of my container that did not mix completely. My mold still set up perfectly, though!

I am very impressed with the detail the finished mold was able to capture. I went ahead and made up a batch of melt and pour to make my embeds, and the soap raspberries are SO detailed that they even have the little hairs sticking out! They’re absolutely amazing!

I definitely see myself purchasing a gallon (or five) of this stuff in the future. I have so many ideas for objects to mold for soaps and cakes! Is this a craft you would add to your repertoire? How might you use silicone mold making in your art? Let me know in the comments below!