As candle and soap makers, we’ve used countless molds of all shapes and varieties. But using a mold and making a mold are two, completely separate things. As we started this process of creating the molds that we’ve always felt were missing from the mold world, we were entering completely new territory. We had never made a mold or worked with silicone before, so we were just learning everything as we went.
Thanks to the excellent tutorials and videos over at Smooth-On.com, we were able to learn a simple mold making process and adapt that to suit our needs. The videos and tutorials Smooth-On has made available were invaluable to us in our first attempt at mold making, and anyone who wants to learn about mold making, casting, or silicone in general should definitely head over to their site.
For our first mold attempt, we chose a contoured 3D bar of soap for our casting subject. We wanted a contoured surface and some detail in the bar, in order to test the silicone’s properties and make sure it could capture the detail and hard lines we were looking for.
The mold box was crafted from plexiglass purchased at a hardware store and cut down to size. If you are looking to make a mold box and can get pre-cut plexiglass, do it!
Otherwise, buy the thinnest sheet that will accommodate your needs. Cutting thick plexiglass without the proper tools is not fun – just sayin’.
Picking the right clay was more important than we thought. After making a few purchases and not being happy, we decided on Monster Clay. This stuff is easier to work with and holds up better than some of the other clay we tried. Pro-tip: If you’re using the Smooth-On mold method and need a deep bed of clay, Monster Clay melts easily and pours great. Just be EXTREMELY CAUTIOUS, as molten clay is sticky and well, molten.
Smooth-On NV silicone was our choice for these first few prototypes. We don’t envision using this product for our production models, but for prototyping and testing purposes it should suit our needs. Disposable mixing containers and good mixing sticks are a must for using this stuff. We recommend 12in-15in metal rulers for mixing sticks – they work great and WIPE CLEAN!
Our first task was to get down a good bed of clay. We melted some Monster Clay and then poured it into the mold box and let it sit. Once semi-dry, but still workable, we added the casting subject, pour spout, and acorn nuts. Once the clay was fully dried, we were able to pour the first layer of silicone.
With the first layer of silicone fully cured, we extracted it from the mold box and removed the clay bed and acorn nuts. Re-mounting the silicone into the mold box was easy, and we were ready to pour the next layer after a quick round of release spray.
After the second layer was cured, we popped them both out of the mold box, and lo’-and-behold, we had a mold! The edges were clean, the keys inside fit great, and the detail that was captured really impressed us. Overall, we were really pleased with our first mold attempt.
Thanks for checking out our first attempt at mold making, and be sure to check back soon for our next update, where we’ll actually use the mold we created to pour a bar of soap and further test the idea!