This butt plug mold is a complex, hybrid glove/3D printed mold that demonstrates advanced techniques for making a seamless sex toy of any shape or complexity.

Two-part molds are simple and easy to make, but they leave a seam down the center of the toy that must carefully be trimmed away. This model allows you to get around this problem by creating a "matrix mold," which is a hybrid of a normal two-part mold and a glove mold. You'll assemble a two-part mold that's a little larger than the sex toy, insert a 3D printed positive of the sex toy, then pour soft 00-20 silicone in the space between. Once it cures, take the outer halves of the mold apart, and peel the silicone glove off the positive.

Turn the glove inside out, spray it with mold release agent, then turn the glove right side in again, place it inside the halves of the outer mold, and pour firm silicone into it. When the silicone sets, remove it and the glove from the mold, peel off the glove, and you'll have a seamless sex toy!

This technique allows you to make extremely sophisticated shapes, including shapes with undercuts, without seams on the finished piece.

If you're making your own models for sex toys in a 3D modeling program, you'll start by creating your sex toy design. When you're happy with it, create a copy of it, offset the copy by about 4mm or so (so that it expands uniformly in all directions), then do a Boolean subtraction of the copy from a block to make your outer mold. Attach a base to the original sex toy design that fits over the mold, with pins to hold it centered. Then print the mold and the original with base to create your hybrid mold.

What You’ll Need

• Shore hardness 20 silicone for the body (I recommend Smooth-On Dragon Skin 20)
• Coloring (I use cosmetic-grade mica powder)
• Mold Release (absolutely essential when you use silicone molds)

Optional

• 3D Print Smoothing Epoxy