How to Make Silicone Molds | Practical Moulding Guide

Molds are some of the most underrated innovations of the human race, be it in the Bronze Age or modern-day manufacturing. 

With the development of technology and complex materials, there has been a rise in the accessibility of making molds. Different materials have been made to have an increasing amount of efficiency. All this has culminated into the production of the most ideal materials to make molds. 

In particular, silicone is a material that is used widely to create custom molds. It’s versatile and used by a variety of people from manufacturers, DIYers, and chefs. 

But is it possible to attain the same level of quality in your own home that professionals use? Of course! We have researched the best methods to make silicone molds no matter how large of an object you are working with. 

With that being said, let’s get into it!

How To Make Silicone Molds

1. Mixing The Silicone

Before making any custom molds, you need to make the silicone itself. Begin by filling a bowl with some water and liquid soap at room-temperature. It doesn’t matter which type of soap you use, so long as it is liquid. 

Try to keep the ratio of soap to water as 1:10. In other words, the overall amount of water should be enough to cover your hand completely. 

Additionally, liquid glycerin or cornstarch is a suitable alternative to using liquid soap. These will both cause the silicone to clump up better when it is mixed in. If you decide to go the cornstarch route, add in twice as much to act as the bonding agent. 

Once the mixture is ready, the construction silicone or silicone caulk can be added. Remember that there must be enough silicone to cover your item to replicate the mold. Also, if your silicone does not have an included syringe to extract the solution, you may have to use a caulking gun. 

Furthermore, drops of acrylic paint can be added to the mixture before kneading to create a colored mold. This can help in color-coding your molds or simply as an aesthetic touch; it does not affect the efficiency or consistency of the mixture. 

2. Working The Silicone

Altogether the kneading process of the silicone can take up to five minutes. Make sure you have gloves on to keep the silicone from sticking to your hands. Another important precaution is to keep the hardening silicone submerged so it doesn’t dry out. 

Start off by firmly squeezing the silicone mixture in your fist and work it together into a solid mass. Once the silicone is formed and malleable, you can remove it from the bowl and begin molding it into a ball with your palms. 

At this point, the silicone is ready to be turned into a mold. Place it onto a flat surface and press down on it to make a wider surface area to place the item being molded. Keep in mind the silicone needs to be thicker than the object being molded. 

3. Creating And Using The Mold

Now that your silicone is ready press the object to be molded into the silicone disc. If the silicone is still sticky you can use a bit of liquid soap to form a thin layer on the surface. 

What’s more, the object pressed into the mold needs to be placed with the overall design facing downwards. So, keep an eye on the edges of the object and adjust the mold till there are no more gaps. 

Wait a few hours till you can touch the silicone without making any changes in its shape. It should be able to hold itself up and support the item. Silicone is not a material that fully hardens, but it solidifies enough to be worked with without falling apart. 

Next, remove the item from the mold by peeling the silicone away from it. As the silicone is now fully flexible the object should be removed easily. And the mold is ready to be used. 

Fill the recess of the mold with clay or the material you are working with, allowing it to harden and dry. Once it has been set and cured in the mold, remove it in the same way as the original object. You should end up with a perfect replica of the initial item placed in the silicone. 

How To Make A Two-Piece Silicone Mold 

Larger items may not be able to fit on a silicone mold using the one-piece method. This is where having a separating mold can come in handy. It is essentially cutting the master object (object to be molded) in half and creating two separate molds and joining the resulting pieces. 

1. Make The Mold Housing

Mold housings are used in manufacturers’ molds to accommodate larger items. To replicate this same housing method in your own home, you can use any plastic container with a cut-out bottom. 

Start by, lining strips of tape overlapping each other in rows across one open bottom of the container to create a removable surface. Make sure the tape is securely fastened to the very edges of the container and there are no gaps between the tape. 

The idea is to have the tape contain the silicone while it sets around the master object. Now that you have your silicone housing ready you can begin making the two-part molding. 

Also, these silicone housings can be used in the same way as a one-piece silicone mold. Simply remove the tape when the silicone is set to remove and use the mold. 

2. Pouring The First Half

An alternative to using liquid soap or cornstarch is a two-part silicone kit. Mix each part of the silicone mix according to the manufacturer’s instructions. And make sure you follow these instructions as closely as possible to have the best silicone consistency. 

Place a bed of clay on the bottom of the model housing to hold the master upright. This clay should cover the bottom half of the master while the top half peeps out of the clay’s surface. 

Pour in the silicone and allow it to set around the exposed half of the master. Extract it by removing the bottom layer of the housing. The clay, master, and silicone should come out easily; it is okay if they separate from each other during this process. 

3. Pouring The Second Half

At this point, you should have one-half of the two-part silicone mold. Repeat this process for the other half of the master. 

Follow the same steps of laying a clay bed and positioning the master half in the clay. Only the previously submerged surface of the master should be exposed from the clay. 

Pour in the silicone until the master is submerged and allow it to set. Remove the silicone, clay, and master from the housing and clean out the clay from the silicone portion. 

4. Using The Two-Part Mold

Now you have two molds that are essentially two halves of the whole master. To use it, join the two halves together and pour in the end-use material be it clay, wax, or concrete. 

Once the material has been set and cured, simply pull the two halves apart. The silicone should peel away easily from the casting in the same way as a one-part silicone mold. 

One-Piece Vs. Two-Piece Silicone Molds

Now that you know how to make two types of silicone molds, what is the better option to use for your own molds? These unique molding techniques have unique advantages and disadvantages that can be useful to your project. 

1. Casted Piece Design

Both these molds give different types of shapes in the resulting pieces created. When removed from the mold, the piece’s final shape varies depending on the method used. 

In a one-piece mold, there is a flat edge to the casted piece when removed. This is due to the method of creating the mold; the bottom of the silicone mold is placed on top of the flat surface. 

As a result, the resulting pieces created from a one-piece mold have a flat side to replicate this flat surface. This makes it an ideal method to use for pieces that need to be stood up or with a stable base. 

On the other hand, a two-piece silicone mold is more cohesive in creating a 360-degree recreation of a master. It wraps fully around the master to create a perfect replica of the master’s shape. 

2. Maintenance 

Depending on the level of work you are ready to put in, one method of silicone molding may be more preferable to the other. Additionally, the amount of work involved when using the mold varies across methods. 

One-piece molds are typically easier to create, but they are not always the easiest to use. These molds have the disadvantage of being susceptible to breaking complex shapes. 

If the master has undercuts in its design, it can be a challenge to remove the molded pieces. The undercut areas catch onto the surrounding silicone mold and can cause potential cracks and weak spots. 

However, complex shapes that need to be recreated in their entirety will benefit from a two-piece mold. What’s more, these are easier to work with as the cavity of the mold is within the silicone. Removing it is easy too, simply pull each piece of the mold from the end-use material to get the resulting casted piece. 

One caveat to using a two-piece silicone mold is the resulting seam lines that can pop up. This is why making sure both ends are securely joined together while the use-material sets in the cavity are so important. 

Additionally, two-piece molds involve much more work to create as compared to a simple one-piece silicone build. If not having a flat edge is a necessary requisite in the master, then a two-piece mold is the only option. 

Special Silicone Features

What makes silicone such an ideal material to use in molding objects? These are a few key features of silicone, as well as a couple of additional features, that can come in handy when working with molds. 

1. Durability

Molds are designed to be able to recreate an object’s likeness multiple times with accuracy and efficiency. Silicone is a material that is able to hold up and retain a shape, while still being somewhat flexible. 

As with any material used in DIY, silicone is subject to breaking down with repeated use. Heavy usage of the mold can cause the silicone to break apart quickly if not maintained. 

Cleaning out the mold with mild soap and water is a good preventive measure to make the mold last longer. Additionally, drying them out and storing them flat can increase the lifespan of a mold. 

2. Flexibility

Molds can be quite stubborn when trying to separate the cast piece from the mold itself. This is why silicone is so favored in mold-making. 

The consistency of silicone allows it to bend and be plied easier than other materials. This makes the removal of silicone from the cast piece a simple matter of peeling it away. 

Additionally, you won’t have to worry about the silicone being broken or stretched out of shape. With a possible elongation of up to 700% times its original size, silicone is by no means a rigid material to work with. 

3. Safety 

Standard silicone types may not be the safest to use for various reasons. Two common cases are when the mold is in contact with food items or direct skin contact. 

Chefs use food-safe silicone to create molds of food items that need to be recreated exactly. It can also help bring a uniform aesthetic to dishes when putting together a plate. 

Furthermore, making a mold of a body part can be irritating to the skin if a standard silicone mix is used. That is why using a skin-safe silicone formula is essential if doing live-casting. There are kits that can be used as a one-time use or, for multiple moldings, alginate can be used. 

Wrapping Up

At the end of the day, there is no right or wrong way to go about using molds; experimentation is the beauty of DIY tasks. 

Knowing the strengths and weaknesses of each type of mold will allow you to combine methods to achieve complex pieces. For simple objects with a stable, flat base, a one-piece silicone mold is the way to go. However, the more complex two-piece mold will allow for a higher quality reconstruction of the master object. 

Whatever method and type of mold you choose to go with, one constant is evident. The recreation of items is a beautiful art that allows for an infinite number of possibilities, so get creative with it!

Related Articles

What To Serve With Quiche [All You Need to Know]

10 Best Personal Mini Pie Makers That Will Sweeten Your Party

11 Best Egg Cooker  [Buyer’s Guide]

13 Best Pastry Mat [Reviewed & Buyer’s Guide]