How to make a silicone adult toy from a 3D print
This guide was drafted with AI assistance.
Design or download the shape as a 3D model, print it as a master, sand and seal it, then make a silicone mold of it in a printed shell. Cast platinum-cure silicone (Dragon Skin 10 is the usual pick) into that mold, and the finished piece is 100% body-safe silicone. The print itself never touches skin. Meshcast's silicone mold maker turns your STL into the printable mold shell, free.
Whether it is a dildo, a plug or a shape nobody sells, a custom design gives you the exact size, shape, firmness and colour you want, which is why so many people make their own. The work is mostly in the first mold: after that, each new cast is half an hour of mixing and pouring. This page is the practical, non-graphic version: what to design, how to mold it, and the safety rules that decide whether it is body-safe.
Safety first: three rules
Platinum-cure silicone only
The datasheet has to say platinum or addition cure, and the maker has to state it is skin-safe once cured. Never tin-cure silicone, and never an unlabelled marketplace kit. Why it matters.
A flared base on anything for anal use
The base must be clearly wider than the body so it cannot slip in completely. This is the single most important design rule, and it is why emergency rooms see the cases they do. Build it into the model before you mold anything.
No rigid parts inside, nothing printed on the outside
The finished piece is silicone all the way through. A printed insert or a rod is exposed if the silicone ever tears, and a printed surface cannot be cleaned. For a firmer inside, use a firmer silicone core instead: see dual-density casting.
Design rules that make it moldable
Sculpt in Blender or Nomad Sculpt, or start from a downloaded model. These details decide whether the mold and the cast go smoothly:
| Detail | Rule of thumb | Why |
|---|---|---|
| Base | Flat, and wider than the body (see rule 2) | The base is also the pour opening, and a flat base stands the mold up straight |
| Suction cup | A shallow dish in the base, sculpted on the master | It casts in one piece with the rest, no separate part |
| Size | Model it in real millimetres and check the dimensions | The mold tool shows real sizes; a model in the wrong units arrives 10 or 25 times off |
| Texture and ridges | Fine, as long as nothing hooks back sharply | A soft glove mold peels off ridges; deep hooks can tear the mold |
| Thin parts | Keep flexible parts over about 10 mm thick | Thin soft silicone tears first |
| The model itself | One closed, watertight mesh | Mold generators need a solid to wrap. Meshcast repairs small holes automatically |
Print and finish the master
Every mark on the master shows up on every cast, so the finish is worth the time:
- Print it standing on its base at 0.12 mm layers or finer, in PLA or PETG. A resin print is smoother but must be fully washed and post-cured, because uncured resin stops platinum silicone curing.
- Sand from about 220 up to 600 grit, then brush on two thin coats of an epoxy coating made for prints (XTC-3D is the common one). Let it cure for a full day.
- Put a small blob of silicone on the finished master before the real pour. If it cures firm, go ahead. If it stays tacky, something is inhibiting it.
- Glossy master, glossy cast. A final light pass with 400 grit gives a silkier, less grabby surface.
Make the mold
For this shape, a glove mold is the best fit: a thin, even layer of silicone around the master, held by a rigid printed shell. It peels off the master like a sock, uses little silicone, and leaves no seam across the surface. You stand the master on its base, pour the mold silicone into the shell around it, let it cure, then peel the glove off.
- Mold silicone: a platinum mold grade (Mold Star or Rebound, for example). Tin-cure mold silicone can stop the platinum cast from curing against it.
- Release, every time: silicone bonds to silicone. Coat the inside of the glove mold with a silicone-on-silicone release (Ease Release 200 or similar) before each cast, or the cast and the mold become one piece.
- Quick test first? You can also print a rigid two-part mold and pour straight into it. The cast will show the print's layer lines, so it is good for checking size and shape before committing. Both routes compared.
Pick and pour the silicone
| Feel | Silicone | Notes |
|---|---|---|
| Soft but holds its shape | Dragon Skin 10 (Shore 10A) | The usual first choice. Tough, 20-minute working time, 5-hour cure |
| Firmer | Dragon Skin 20 (Shore 20A) | Very tough, springy |
| Very soft | Ecoflex 00-30 or 00-50 | Floppy on its own; best as the outer layer over a firmer core |
| Firm inside, soft outside | Dragon Skin 20 or 30 core, softer skin | Dual-density method |
More detail in Ecoflex vs Dragon Skin. To pour:
Weigh, colour, mix
Stir each part in its own container, weigh 1:1 on a 1 g scale, add a pigment made for platinum silicone (up to about 3% by weight), and mix for three minutes, scraping the sides and bottom.
Degas
Dragon Skin is thick, so a vacuum chamber makes a real difference: the silicone rises three to four times, collapses, and comes out bubble-free. Without one, use Dragon Skin 10 Slow for more time and pour from high up in a thin stream.
Pour into the base opening
With the glove mold in its shell, base opening up, pour in one thin continuous stream down the side so the tip fills first and pushes the air out. Fill slightly past the top; the excess is trimmed to make the flat base.
Demold and finish
- Wait the full cure time, longer in a cold room. Then peel the glove mold off from the base end.
- Trim the base flat with a sharp blade and any flash with small curved scissors.
- Wash with warm water and mild unscented soap to remove the release agent. Optional: the datasheet's heat post-cure (2 hours at 80 °C, then 1 hour at 100 °C), after demolding.
- Use a water-based lubricant with it: silicone-based ones can soften a silicone surface over time.
- If any part feels tacky and soft, it did not cure. Do not use it; cast again.
Step by step in Meshcast
Upload the STL
Open the silicone mold maker in contoured mode and upload your model. Check the dimensions it shows in millimetres.
Set the silicone thickness
This is the thickness of the glove mold. Around 8 to 10 mm is a good start; thinner saves silicone, thicker is sturdier.
Let it place the split
The printed shell splits into parts so it can come off the cured glove. Turn for a cleaner seam and Best split pick the orientation, and air-pocket pins show where air would be trapped.
Download, print, pour
Download the shell, base plate and clips, print them in PLA or PETG, and pour. The same shell holds the glove mold for every cast after that.
It is free, runs in your browser, and your model is deleted from the server once the mold is built.
Common questions
Can I just 3D print a dildo?
Do not use a 3D print directly. PLA, PETG and resin prints are porous between the layers, cannot be cleaned properly, and most resins are not skin-safe. Print the shape as a master or a mold, and cast the finished piece in platinum-cure silicone.
Which silicone is best for a homemade dildo?
A platinum-cure silicone sold as skin-safe. Dragon Skin 10 (Shore 10A) is the usual choice: soft but it keeps its shape and resists tearing. Ecoflex 00-30 or 00-50 is much softer and floppier, and Dragon Skin 20 is firmer. For a firm core with a soft outside, cast two silicones as a dual-density piece.
How much silicone do I need?
Platinum silicone weighs about 1.07 g per ml, so take the model's volume from your slicer in ml, multiply by 1.07 and add 10 to 15 percent for what stays in the cup. A 200 ml design needs roughly 240 g. The mold needs more on top, unless you use a thin contoured mold.
Is my model private if I upload it to Meshcast?
The silicone mold generator sends the model to the generation server only long enough to build the mold, then deletes it. A small preview screenshot of each generation is kept for 30 days, visible only to the Meshcast team, and uploads are never shared, published or used for training. Details in the privacy policy.
Made by meshcast.app. Stuck on a mold? Email us, discreetly, and we will help.