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Smooth-On Mold Star 30 Silicone Mold Making Kit - Easy to Use & Long-Lasting Silicone Mold (2-Pound)

Based on 749 reviews
Condition: New
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$39.99
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Arrives Saturday, Nov 14
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At a glance

Condition
New
Size
Pint Unit
Model
COMINHKR067156
Dimensions
7.52 x 5.98 x 2.99 in
Weight
2.5 lb
Color
Blue
Material
Silicone

Features 4

  • Mold Star silicones cure to soft, strong rubbers which are tear resistant and exhibit very low long term shrinkage
  • Molds made with Mold Star will last a long time in your mold library and are good for casting wax, gypsum, resins, and other materials
  • Easy to use platinum silicone mold mix
  • Cures to a soft, stong, tear resistant rubber

Description

Mold Star silicones cure to soft, strong rubbers which are tear resistant and exhibit very low long term shrinkage. Molds made with Mold Star will last a long time in your mold library and are good for casting wax, gypsum, resins, and other materials. Cured Mold Star rubber is heat resistant up to 450°F (232°C) and is suitable for casting low-temperature melt metal alloys. Mold Star rubbers are mixed 1A:1B by volume (no weighing scale necessary) for precise measurements even at a very low mass and cure at room temperature with negligible shrinkage. Mold Star silicones feature relatively low viscosities making vacuum degassing optional and is not required for most applications. A uniform flow will help minimize entrapped air. 14T, 19T, 20T, and 31T fast curing silicones for making molds or casting into alginate molds. They offer an infinite number of color effects achieved by adding Silc Pig silicone pigments or Cast Magic effects powders. Mold Star 16 is available in a 400ml cartridge and is one of the fastest ways to make a silicone mold. With a 6 minute pot life and 30 minute cure time It can even be used in forensics to capture evidence impressions in the field.

Specs 16

Material Silicone
Color Blue
Brand Smooth-On
Item dimensions L x W x H 7.52 x 5.98 x 2.99 inches
Shape Star
Brand Name Smooth-On
Number of Pieces 1
Manufacturer Smooth-On, Inc.

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If you place your order now, the estimated arrival date for this product is: Saturday, Nov 14

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Top Amazon Reviews


Survived my chaos and still made a perfect mold
Size: Pint Unit
I bought this for a “quick little project” which somehow turned into me panicking, spilling silicone everywhere, trapping objects in glass containers, and questioning my life choices at 2 AM. And honestly? This silicone still performed beautifully. The mix ratio was easy enough that even a sleep-deprived beginner could handle it, the bubbles were minimal, and the cured mold came out flexible, strong, and super detailed. I used it for casting decorative pieces and it picked up every tiny texture perfectly. Biggest surprise: it actually gives you enough working time before curing, so you’re not fighting the clock like in some other products. Demolding was also way easier than expected. A few helpful notes for beginners: * Mix slowly if you want fewer bubbles * Don’t underestimate how well this stuff sticks around once spilled * Use gloves unless you want “mysterious silicone fingerprints” on everything you own for 3 days Overall, excellent product. My project survived, my sanity mostly survived, and now I want to mold everything in my apartment. ... show more
Reviewed in the United States on May 18, 2026 by İbrahim Kaya

The Perfect Product for Artists and Engineers
Size: Pint Unit
I've been following this company for quite a while and I've used some of their other products such as Body Double and the level of quality in the final molds are breathtaking. What drew me to using Mold Star 30 is not only it's easy mix ratio of 1:1 by volume (you can also mix by weight, which I did for my current project in the pictures), its low viscosity makes cast complex parts and 3d prints easy. When you get these, stir each jar VIGOROUSLY with SEPARATE mixing sticks (I used a silicone stir stick or a drill with a mixing paddle, just drill slowly)! Not using separate sticks will cause cross contamination and you'll ruin the material. I also love the colours which helps with knowing when it's mixed, you don't want streaks in it. Now, prepping your part for molding takes some planning on your part and having sulfur free plastilina clay is HIGHLY RECOMMENDED and IMPORTANT, especially on wood mold boxes. Once the two parts are mixed in a cup you have 45 minutes to pour it into the mold. And I like that because I'm not rushing to pour and 45 minutes is PLENTY of time to stir the material and ensure a proper mix. In that time, you check your dry mold, fix a few things, and even take time degassing the silicone (the vacuum pot is optional). After pouring, you'll have to wait 6 hours until it cures. I ended up sitting the mold outside overnight to cure and doing this on a hot summer night helps immensely, especially when using the cups to check on curing. It was 97°F when I poured the silicone and the leftover material was already fully cured 3 hours later! Wow. The only knock I have on this product is the pricing for a pint and the price kept fluctuating here on Amazon, but you get what you pay for. This stuff is high quality and having a few pints actually is a good thing too, so you'll actually use it. Overall, this is easy to use but the learning curve mainly hinges on how well you plan your design and your mold boxes. Also, doing this outdoors helps with odors depending on what region you're in, especially where the air is drier. Once the price falls back to normal, I'll be getting more of these. ADDENDUM: My masters are done in PLA. For those of you who are using resin printed models, make sure the resin is COMPLETELY UV CURED before using this. ... show more
Reviewed in the United States on June 26, 2022 by KRGraphics

Amazing
Size: Pint Unit
⭐️⭐️⭐️⭐️⭐️ Excellent Quality Silicone for Molds!. Silicone is fantastic! It’s easy to mix and pour, and it captures every fine detail perfectly. The curing time is very reasonable, and once set, the mold is strong, flexible, and durable — perfect for resin, clay work. releases cleanly, making the whole process so much easier. This silicone gives professional-quality results every time. I’ll definitely keep using it for all my future projects! ... show more
Reviewed in the United States on October 22, 2025 by iris

Works great, nice finished product
Size: Pint Unit
Works great and just as advertised as long as you follow the directions. The manufacturer recommends you pour equal amounts of part A and B into separate containers, stir them, then mix together in a separate container and stir, after which they say to pour into a fourth container to finish mixing. I've made a few batches now and as long as you be sure to mix very well (no limp-wristed stirring) then you should be fine without pouring the mixture into a fourth container to finish mixing. Just scrape the sides and bottom of the container well, and the pot life is 45 minutes, so you won't run out of time mixing (not even close). The finished silicone produces a semi-hard but pliable rubber. I'd compare it to the rubber that condensation-catching mats are made from, the kind that line a bartop (can't think of a better name for them), maybe just a little harder than those though. I made a few molds for concrete out of this, and while they weren't the most intricate there were still some angles in the one-part molds that I was worried could wear or break when pulling the concrete out. The silicone has been pliable enough to remove it with some force, while still snapping back to its original shape. I'm sure on a microscopic level, all the pulling will wear it out faster, but I couldn't see anything from looking closely. If you're making a mold of something that has a few turns or twists, or strange angles, I'd recommend a two-part mold. It will also grab detail from whatever you're making the mold from, which is both good, and also something to keep in mind as any imperfections left of the surface of your positive will also be on any reproductions made from the mold. ... show more
Reviewed in the United States on October 18, 2016 by Brotato

Great for quality molds
Size: Pint Unit
This has been a go to for me for quite a while. It's somewhat thicker, so helps with leaking through the smallest spaces. Very easy to use, and I've had great luck getting a high level of detail in my molds. I really haven't had much trouble regarding quality and durability of molds I've made. I can usually get a very reasonable amount of castings before the molds start to show wear. I'm sure there is better stuff out there, but I'm very satisfied with the quality I get out of mold star. ... show more
Reviewed in the United States on September 29, 2025 by Jackie Neubauer

Pretty good, but had unequal amounts.
Size: Pint Unit
The seller I got this from did a terribly job of packing the items. They were in rough shape when they were delivered, but the product worked just fine. The only issue is that in the part A and B containers, I received more of one than the other. So there was a wasted amount that I couldn't use, which isnt great. I hope smooth-on measures their amounts better in the future for their kits. I could have done another small mold if there was equal amounts of both parts. ... show more
Reviewed in the United States on October 20, 2020 by tymarbry

Good stuff. Practice first!
Size: Gallon Unit
This stuff is pretty good. Sets up way faster than expected from instructions. Mix a little first to monkey with before diving into the deep end. If you've never used this, there is a bit of a learning curve. This is also not the right stuff for brushing on, trust me.
Reviewed in the United States on October 23, 2025 by Joe H

Works great, wish it was not so expensive, but I love how easy it is to work with.
Size: Pint Unit
Works great! Be sure to have a good model planned out for your mold and cast project, otherwise you should not have much issue. I use the mold release as well.
Reviewed in the United States on April 30, 2024 by Benjamin J. Burger
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