- Mold Making Silicones
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There are many types of siliconas on the market. For these kinds of materials, quality, speed and tear resistance are fundamental qualities.
If you're thinking about starting a project where you'll need a quality silicona for molding, this tutorial will guide you on what to consider when choosing one silicona over another and creating highly resistant molds.
Keep reading to find out more about Feroca's unbreakable silicona mold.
Materials for making a silicona mold
Feroca's Silicona PlatSil FS20 is a translucent, fast-curing, high-resistance silicona, ideal for platinum molds.
It has an average working time of about 8 minutes and a very fast cure time of around 20 to 25 minutes. Times will vary depending on the ambient temperature at the time or the season of the year. We recommend an average temperature of around 23°C.
Likewise, it has incredible tear resistance, being practically unbreakable when pulled. It also has the advantage of being a 1a-1b product that comes in two separate containers, which means it should be mixed in equal parts by weight or by volume.
It's a great option for molds that need to be cut after curing, since the model is visible and the parting lines can be determined more easily. It's also very useful when making molds of complex pieces to ensure that all hard-to-reach areas of the piece have been filled with the silicona.
It has a shore 20, meaning it has more body than its sister silicona, the PlatSil FS10, which is softer.
In addition, the silicona comes with measuring caps that are very useful for preparing small quantities, to measure part a and part b.
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The Silicona PlatSil FS10 is similar to the previous one. What differs from the FS20 is that this one is softer, as it has a shore (hardness and density rating of the silicona) of FS10.
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Feroca's white polyurethane resin EasyFlo 60 is widely used for making copies and reproductions. It's a resin with extremely low viscosity that produces bright white cast pieces that are practically bubble-free.
Like the silicona preparations, it comes in two containers (1A:1B by volume) offering a convenient one-to-one mixing ratio.
Among its many great qualities, it produces resistant, durable, machinable pieces that can also be painted and are resistant to moisture and mild solvents.
Its applications include the reproduction of small to medium-sized sculptures, prototype creation, pieces for rotational molds, and special effects props.

Video tutorial on how to make a highly resistant silicona mold
The following video features the tutorial in which expert Juan Villa demonstrates step by step the incredible tear resistance of the Silicona PlatSil FS20.
The idea behind the video tutorial is to build a formwork to test the tear resistance of the Silicona PlatSil FS20, a silicona that comes in two separate containers (1a and 1b) perfect for mixing.
Step by step: how to make an unbreakable silicona mold
Preparing the resin and the counter-mold
To do this, the silicona will be tested in a counter-mold built for this purpose, which will in turn contain a figure made with Feroca's EasyFlo 60 resin.
Our expert Juan Villa has prepared a unicorn horn with the resin to test the product, and has also built a simple counter-mold in the shape of a vertical rectangle using several pieces of wood and an acrylic sheet.

Next, Villa proceeds to glue the counter-mold onto a base to secure the sample. To do this he uses a hot glue gun, an adhesive that is easy to remove.
The goal of this step is to make sure the mold has no leaks when the silicona is poured in.
The next step is to place the sample resin horn inside the counter-mold and glue it to the base.

Preparing the silicona
The next thing we're going to do is prepare the silicona concentrate. Open both containers of silicona by removing the security seals. The red cap corresponds to the type 'a' mix, and the white cap to the type 'b' silicona.
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Keeping this distinction clear is important to avoid cross-contaminating the material and ruining the product, as Juan Villa explains.
Weighing the silicona
For this project, Juan Villa weighs around 400 grams of silicona in a separate container using a scale.
The 400 grams are split equally into 200 grams of silicona 'a' and 200 grams of silicona 'b', and both are weighed together in the same container.
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After weighing, make sure to mix the product thoroughly even though the silicona is very liquid, as Juan Villa explains.
The advantage of it being a liquid and translucent silicona is that it flows very well and will later allow you to make a clean cut with a utility knife, as Juan Villa explains.
Pouring into the counter-mold
Next, Juan Villa pours the already mixed content into the counter-mold containing the EasyFlo 60 resin figure.
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The expert recommends pouring the silicona from above slowly, stretching it out. The goal is to break any air bubbles in the counter-mold. A vacuum chamber can also be used to achieve this effect.
Being such a fluid silicona, it adheres very well to the walls of the counter-mold and to the proposed resin model, Villa adds.
Demolding the silicona
After pouring the silicona, you need to wait around 20-25 minutes for it to cure before removing the counter-mold and proceeding with demolding.
As Villa explains, the curing time will depend largely on temperature conditions and variables, which change dramatically between winter and summer. After curing, it's time for demolding.
You can use a metal spatula or a similar tool to help you through the process.
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Cutting and tear test
The result of the previous step is a fully polymerized mold on which we will make a cut with a utility knife to test its tear resistance. Being a translucent silicona, it makes it easier to know where to cut.
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After the initial cut, Juan Villa tries applying force and stretching the silicona to see whether it tears or splits open.
Unlike other siliconas, when force is applied to both sides with your hands, it does not tear.
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The result is a practically unbreakable silicona mold that can be reused to make copies.
Furthermore, the silicona PlatSil FS20 is a very fluid, very liquid silicona that captures all the details of pieces extremely well — it's translucent, with the advantage that it can be tinted or left transparent so you can see where to cut. A true innovation from Feroca.
The best molding and modeling products and tutorials, only at Feroca
At Feroca we have a special commitment to professionalism and the proper use of our products. That's why we offer a wide variety of resources, from video tutorials, to blog articles, WorkShops and live videos so our customers can see all the possibilities our products offer and use them with complete confidence.
We work with recognized experts like Juan Villa to help you learn more about the art of molding and casting, which is our specialty. Our relationship with our customers is what sets us apart. Browse our website and social media to discover all the options we have to offer you.
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