Ecoflex vs Dragon Skin: which silicone to choose
This guide was drafted with AI assistance.
Ecoflex is softer and pours like cream, so it is easy to get bubble-free, but it tears more easily. Dragon Skin is firmer, pours like honey, and is two to three times tougher. Want squishy? Ecoflex 00-30 or 00-50. Want soft but holding its shape, or thin parts that flex a lot? Dragon Skin 10. Want a firm core or a durable grip? Dragon Skin 20 or 30. All of them are platinum-cure, mix 1:1, and are sold as skin-safe once cured.
These are the two silicone families most makers end up choosing between, for soft toys, grips, prosthetic and special-effects pieces, soft robotics, and adult toys. Both come from Smooth-On. Other brands sell comparable platinum grades, and everything below applies to them if their datasheet gives similar numbers.
The datasheets side by side
| Grade | Hardness | Mixed viscosity | Tear strength | Stretch | Working time | Cure |
|---|---|---|---|---|---|---|
| Ecoflex 00-30 | Shore 00-30 | 3,000 cps | 38 pli | 900% | 45 min | 4 h |
| Ecoflex 00-50 | Shore 00-50 | 8,000 cps | 50 pli | 980% | 18 min | 3 h |
| Dragon Skin 10 Medium | Shore 10A | 23,000 cps | 102 pli | 1,000% | 20 min | 5 h |
| Dragon Skin 20 | Shore 20A | 20,000 cps | 120 pli | 620% | 25 min | 4 h |
| Dragon Skin 30 | Shore 30A | 20,000 cps | 108 pli | 364% | 45 min | 16 h |
From Smooth-On's technical data at 23 °C. All five mix 1A:1B by weight or volume and shrink less than 0.1%. "Stretch" is elongation at break.
What the numbers mean in your hands
| Number | What you notice |
|---|---|
| Hardness | How it feels to squeeze. 00-30 is jelly-soft, 00-50 is soft, 10A holds its shape but squishes, 20A to 30A feels firm and springy |
| Viscosity | How it pours. 3,000 cps is like cream, and bubbles float out by themselves. 20,000 cps and up is like honey: it traps bubbles and really wants a vacuum chamber |
| Tear strength | How well it survives a nick, a thin edge or a hard pull out of the mold. Dragon Skin is roughly two to three times tougher than Ecoflex |
| Working time | How long you have to mix, colour, degas and pour. Under 20 minutes is tight if you degas |
| Cure | When you can demold. Longer in a cold room |
Which one to pick
| You want | Pick | Why |
|---|---|---|
| Your very first silicone cast | Ecoflex 00-30 | Forgiving: long working time, thin enough to degas without a vacuum chamber |
| Squishy, jiggly, very soft | Ecoflex 00-30 | The softest of the common grades |
| Soft, a bit more body and toughness | Ecoflex 00-50 | Still pours easily, but work fast: 18 minutes |
| Soft but keeps its shape; thin flexing parts | Dragon Skin 10 | Soft enough to squeeze, tough enough not to tear at edges |
| A firm core, a grip, something that takes wear | Dragon Skin 20 | The toughest of the five, still flexible |
| Firm and springy, lots of working time | Dragon Skin 30 | 45-minute pot life, but plan for a 16-hour cure |
| Soft outside, firm inside | Both | A Dragon Skin core with an Ecoflex skin. See dual-density casting |
Softer, firmer, less tacky
- Softer and more flesh-like: Smooth-On's Slacker additive works with Dragon Skin 10 and Ecoflex 00-30 and 00-50. The catch, in the maker's own words: tackiness increases in direct proportion to the amount added.
- Thicker, for brushing: THI-VEX thickens these silicones so they stay on vertical surfaces, for brushed-in skin layers and brush-on molds.
- Less tacky: a firmer grade, a lightly matte mold surface, or a dusting of cornstarch after demolding.
- Never thin or colour them with anything not made for platinum silicone. It can stop the cure and it ends up in a piece that touches skin. Safe and unsafe additives.
Skin safety
Smooth-On states that cured Ecoflex 00-30 and cured Dragon Skin 10 are skin safe and certified by an independent laboratory. Two conditions make that true for your cast: it has to be fully cured everywhere (a tacky patch is uncured silicone; see silicone not curing), and nothing can be mixed in that is not made for it.
Both datasheets also give an optional heat post-cure (2 hours at 80 °C, then 1 hour at 100 °C) that brings the rubber to its full properties. Do it after demolding: a PLA mold softens at around 55 °C.
How much to buy
Both families have a specific gravity of about 1.07, so 1 kg makes roughly 930 ml of cured silicone. Work out your part's volume (your slicer shows it for the STL at 100% infill), add 10 to 15% for what stays in the cup, and buy a kit at least that size. For the mold itself, the silicone calculator gives the volume of a block mold from your object's size. A contoured mold from the silicone mold maker needs far less than a block.
Common questions
What is the difference between Ecoflex and Dragon Skin?
Both are platinum-cure, 1:1 silicones from Smooth-On. Ecoflex is softer and much thinner when mixed, so it pours and degasses easily, but it tears more easily. Dragon Skin is firmer, thicker to pour and roughly two to three times more tear-resistant, so it holds its shape and survives thin sections and repeated flexing better.
Is Ecoflex or Dragon Skin softer?
Ecoflex. Ecoflex 00-30 and 00-50 are on the Shore 00 scale and feel jelly-like to soft. The softest regular Dragon Skin, Dragon Skin 10, is Shore 10A, which is firmer than any of the common Ecoflex grades.
Are Ecoflex and Dragon Skin skin-safe?
Smooth-On states that cured Ecoflex 00-30 and cured Dragon Skin 10 are skin safe and certified by an independent laboratory. That applies to fully cured material with nothing added that is not made for it. It is a skin-safe claim, not a medical-device certification.
Which is easier for beginners, Ecoflex or Dragon Skin?
Ecoflex 00-30. At about 3,000 cps it is thin enough that bubbles rise out on their own, it has a 45-minute pot life and it cures in 4 hours. Dragon Skin is around 20,000 cps and really wants a vacuum chamber for bubble-free results.
Made by meshcast.app. Not sure which grade fits your part? Email us.