---
product_id: 1871180
title: "Mold Star 15 Slow - 1A:1B Mix by Volume Platinum Silicone Rubber - Pint Unit"
brand: "smooth-on, inc."
price: "€ 85.38"
currency: EUR
in_stock: true
reviews_count: 9
category: "Smooth On"
url: https://www.desertcart.fi/products/1871180-mold-star-15-slow-1a-1b-mix-by-volume-platinum
store_origin: FI
region: Finland
---

# 50 min pot life 450°F heat resistant 1:1 volume mix ratio Mold Star 15 Slow - 1A:1B Mix by Volume Platinum Silicone Rubber - Pint Unit

**Brand:** smooth-on, inc.
**Price:** € 85.38
**Availability:** ✅ In Stock

## Summary

> 🔥 Mold like a pro, no stress, all finesse!

## Quick Answers

- **What is this?** Mold Star 15 Slow - 1A:1B Mix by Volume Platinum Silicone Rubber - Pint Unit by smooth-on, inc.
- **How much does it cost?** € 85.38 with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.fi](https://www.desertcart.fi/products/1871180-mold-star-15-slow-1a-1b-mix-by-volume-platinum)

## Best For

- smooth-on, inc. enthusiasts

## Why This Product

- Trusted smooth-on, inc. brand quality
- Free international shipping included
- Worldwide delivery with tracking
- 15-day hassle-free returns

## Key Features

- • **Rapid Turnaround:** Cures in just 4 hours—get your projects moving faster than ever.
- • **Bubble-Free Detail:** Low viscosity formula delivers crisp, air-free molds without vacuum degassing.
- • **Extended Work Window:** 50 minutes pot life means zero rush, perfect for meticulous pros.
- • **Durable & Tear-Resistant:** Soft yet strong silicone rubber built to last through countless casts.
- • **Effortless Precision Mixing:** No scales needed—just equal parts for flawless molds every time.

## Overview

Mold Star 15 Slow is a platinum-cure silicone rubber offering a perfect 1:1 volume mix ratio, 50-minute pot life, and a 4-hour cure time. Heat resistant up to 450°F, it produces soft, tear-resistant molds ideal for casting wax, gypsum, resins, concrete, and low-temp metals—delivering professional-grade detail without the need for vacuum degassing.

## Description

Smooth-On Mold Star 15 is an easy to use platinum silicone mold mix that cures to a soft, strong, tear resistant rubber. Mold Star 15 molds will last a long time and good for casting wax, gypsum, resins, concrete and more. Cured Mold Star rubber is heat resistant up to 450 degrees F and is suitable for casting low temperature melt metal alloys. Mold Star 15 is mixed to a 1A:1B ratio and has a pot life of 50 minutes and cure time of 4 hours. Mold Star does not require vavuum degassing & is not intended for brush on mold making. Contains 1 lb of Part A and 1 lb of Part B.

Review: Awesome choice for anyone, but especially for beginners - I've tried a lot of molding silicones from a few brands, and so far, this one's my favorite for a handful of reasons. 1. Long pot life means there's ample time to mix and pour before things start to thicken up on you. If you're like me, when you first start making your own molds, you'll find dozens of ways to screw things up. A nice long pot life means that if (or in my case, WHEN) things go haywire, you'll have plenty of time to fix things. Silicone isn't cheap, so mistakes can be expensive -- the wiggle room is nice! 2. Relatively quick cure time, especially given how long you have before the mix starts to solidify. I can come home from work, pour a mold, and it's ready to use with time to spare before I need to head to bed. 3. Platinum cure is always a plus. For mysterious reasons, I've had trouble with tin cure silicones and the material I usually cast (epoxy). I think post-curing tin-cure molds is supposed to solve part of the issue, but even when I've tried that, the tin-cure molds have left a slightly tacky, sticky film on the surface of my castings. I've had much better luck with platinum silicones, which actually seem to *improve* how my epoxy resin cures. 4. Low viscosity means you don't get bubbles as long as you don't overmix, and the trapped air in detailed molds doesn't have shove its way through super-thick goop to break free. In other words, unlike a lot of silicones, you can get excellent results with this one without using a vacuum degassing thing-a-ma-bob. The last thing is a plus/minus: This stuff is soft, but not insanely soft. The flexibility makes it excellent for intricate stuff because you don't need Hercules hands to get your casting out of the mold. However, really soft, flexible silicone like this can also cause some problems. So here are a couple tips I learned the hard way :). 1. If you'll be casting something in multiple layers, make sure you either place your mold in some kind of support shell -- a cup or a plastic bowl can work -- or make your mold with extra "buffer" rubber on the base and the sides. Why? Well, if you move the mold too much, those awesome natural silicone release properties can work against you and knock your layer loose, which means the next layer can ooze down the sides. Having something to make sure the soft mold doesn't get jostled makes all the difference. 2. On a similar note, if you're going to make one mold with lots of cavities, it's probably best to time things to everything is ready to be popped out of the mold at the same time. The flexibility means it's pretty easy to accidentally knock one casting loose while trying to remove another one. All in all, a really awesome product. Highly recommended!
Review: Excellent Silicone and Even Better Support - Mold Star 15 Slow has been fantastic for my projects. It captures fine detail really well and gives me consistent, bubble-free results. The longer working time is a huge plus when I need extra time to get everything just right. But what really stood out was the customer support. I reached out to Smooth-On directly to figure out which silicone would be best for what I was doing, and they walked me through everything step by step. Later, when I had some trouble with my mixing technique, they were super helpful and patient—totally saved me from wasting materials. Great product backed by a great team. Highly recommend it if you're getting into mold making or want something reliable with solid support behind it.

## Features

- Easy to use platinum silicone mold mix
- Cure to soft, strong, tear resistant rubbers
- Good for casting wax, gypsum, resins, concrete and more
- Pot life of 50 minutes and cure time of 4 hours
- Mix ratio is 1A:1B by volume- no weighing scale necessary

## Technical Specifications

| Specification | Value |
|---------------|-------|
| ASIN | B00ATDV5BQ |
| Best Sellers Rank | #17,866 in Arts, Crafts & Sewing ( See Top 100 in Arts, Crafts & Sewing ) #167 in Sculpture Molding & Casting Products |
| Brand | Smooth-On, Inc. |
| Color | Green |
| Customer Reviews | 4.6 4.6 out of 5 stars (2,185) |
| Date First Available | December 26, 2012 |
| Is Discontinued By Manufacturer | No |
| Item Weight | 2.4 pounds |
| Item dimensions L x W x H | 7.6 x 5.9 x 3.1 inches |
| Item model number | SOMoldStar15kit |
| Manufacturer | Smooth-On, Inc. |
| Material | Silicone Rubber Metal |
| Number of Pieces | 1 |
| Product Dimensions | 7.6 x 5.9 x 3.1 inches |
| Shape | Star |
| UPC | 751635292413 |

## Product Details

- **Brand:** Smooth-On, Inc.
- **Color:** Green
- **Item dimensions L x W x H:** 7.6 x 5.9 x 3.1 inches
- **Material:** Silicone Rubber Metal
- **Shape:** Star

## Images

![Mold Star 15 Slow - 1A:1B Mix by Volume Platinum Silicone Rubber - Pint Unit - Image 1](https://m.media-amazon.com/images/I/41Axo7OP4YL.jpg)

## Available Options

This product comes in different **Size** options.

## Questions & Answers

**Q: Are these pints?  I am looking for the volume, not the weight and I can't seem to find it.**
A: They are pint bottles.

**Q: Is this enough to make a full set of rpg dice molds in small cups?**
A: I ran out after 6 of the 7 dice. I used 4 oz cups and was barely able to make the six molds. The molds did turn out great, though!

**Q: How well does this retain fine details?**
A: It does a great job with details.

**Q: What is the shelf life for parts A and B unmixed?**
A: Hey mOWWck, the shelf life is about 1 year (usually slightly longer than that) if you do not use them. This is an approximate number and based on our experiences in keeping the products in our store.  You should, however, place the products in a low humidity area to keep them longer. Do note that unused silicone last longer than unused resins before the products start gradually losing their properties (such as hardness etc.) Hope this helps and have a great day ahead!!

## Customer Reviews

### ⭐⭐⭐⭐⭐ Awesome choice for anyone, but especially for beginners
*by S***C on January 12, 2014*

I've tried a lot of molding silicones from a few brands, and so far, this one's my favorite for a handful of reasons. 1. Long pot life means there's ample time to mix and pour before things start to thicken up on you. If you're like me, when you first start making your own molds, you'll find dozens of ways to screw things up. A nice long pot life means that if (or in my case, WHEN) things go haywire, you'll have plenty of time to fix things. Silicone isn't cheap, so mistakes can be expensive -- the wiggle room is nice! 2. Relatively quick cure time, especially given how long you have before the mix starts to solidify. I can come home from work, pour a mold, and it's ready to use with time to spare before I need to head to bed. 3. Platinum cure is always a plus. For mysterious reasons, I've had trouble with tin cure silicones and the material I usually cast (epoxy). I think post-curing tin-cure molds is supposed to solve part of the issue, but even when I've tried that, the tin-cure molds have left a slightly tacky, sticky film on the surface of my castings. I've had much better luck with platinum silicones, which actually seem to *improve* how my epoxy resin cures. 4. Low viscosity means you don't get bubbles as long as you don't overmix, and the trapped air in detailed molds doesn't have shove its way through super-thick goop to break free. In other words, unlike a lot of silicones, you can get excellent results with this one without using a vacuum degassing thing-a-ma-bob. The last thing is a plus/minus: This stuff is soft, but not insanely soft. The flexibility makes it excellent for intricate stuff because you don't need Hercules hands to get your casting out of the mold. However, really soft, flexible silicone like this can also cause some problems. So here are a couple tips I learned the hard way :). 1. If you'll be casting something in multiple layers, make sure you either place your mold in some kind of support shell -- a cup or a plastic bowl can work -- or make your mold with extra "buffer" rubber on the base and the sides. Why? Well, if you move the mold too much, those awesome natural silicone release properties can work against you and knock your layer loose, which means the next layer can ooze down the sides. Having something to make sure the soft mold doesn't get jostled makes all the difference. 2. On a similar note, if you're going to make one mold with lots of cavities, it's probably best to time things to everything is ready to be popped out of the mold at the same time. The flexibility means it's pretty easy to accidentally knock one casting loose while trying to remove another one. All in all, a really awesome product. Highly recommended!

### ⭐⭐⭐⭐⭐ Excellent Silicone and Even Better Support
*by C***N on March 30, 2025*

Mold Star 15 Slow has been fantastic for my projects. It captures fine detail really well and gives me consistent, bubble-free results. The longer working time is a huge plus when I need extra time to get everything just right. But what really stood out was the customer support. I reached out to Smooth-On directly to figure out which silicone would be best for what I was doing, and they walked me through everything step by step. Later, when I had some trouble with my mixing technique, they were super helpful and patient—totally saved me from wasting materials. Great product backed by a great team. Highly recommend it if you're getting into mold making or want something reliable with solid support behind it.

### ⭐⭐⭐⭐⭐ Terrific molds, but not for resin prints
*by C***N on August 28, 2024*

This makes terrific strong molds, fast and easy. If you use a single graduated container and pour in the same amount of A and B, then cleanup is very fast and easy because you can just wait for the residue to set up in the container and then it just pulls out all in one piece. The instructions clearly state that it will not set up in the presence of sulfates, but I didn't realize that most resin prints have sulfates. This will work great with regular (FDM) 3d printers, but not for resin printers unless you get special resin!

## Frequently Bought Together

- Mold Star 15 Slow - 1A:1B Mix by Volume Platinum Silicone Rubber - Pint Unit
- Smooth-Cast™ 300: Bright White, Low Viscosity, Liquid Plastic Casting Resin - Pint Unit
- Smooth-On Universal™ Mold Release Spray, 14 fl. oz. Aerosol Can

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*Product available on Desertcart Finland*
*Store origin: FI*
*Last updated: 2026-02-27*