Coating Molds For Resin: A Necessary Step?

Coating a mold is an essential step in the resin mold-making process. This is because the resin will stick to the mold without a release agent, making it difficult or impossible to remove the cured resin object. A light coat of a release agent, such as resin mold release or Silly Putty, is necessary to ensure the resin doesn't adhere to the mold. This step is crucial for successful demolding and should not be skipped.

You must have a template to mould

When creating a resin mould, you must have a template to mould. This is because casting resin moulds are used to make a specific mould of an object you would like to replicate or display. Resin is then poured into the mould to replicate the mould's exact shape, resulting in a 3D object.

There are two ways to create a resin mould: using silicone putty and liquid silicone. Both methods involve making a negative mould of an object that will then be filled with epoxy resin to create the finished piece. Silicone is used for epoxy resin moulds as the polymer doesn't stick to it.

If you choose to make your mould yourself, it is important to ensure you have all the necessary materials before starting. You will need casting resin, mould putty, the item you want to replicate, a razor blade or X-Acto knife, and a timer. Most moulds are made the same way, but it is ideal to follow the directions on your mould putty box to properly use the product.

You can find mould templates online on websites like Etsy, which offers a wide variety of mould templates for different projects, including those for resin art, pottery, soap-making, and jewellery-making. These templates can be downloaded and used to create your own moulds, or you can purchase pre-made moulds from craft stores or online retailers.

Seal a porous model before using it

Sealing a porous model before using it with resin is a crucial step to ensure a flawless, bubble-free result. This is because porous materials have tiny air pockets that can trap air bubbles when resin is poured onto them, which can ruin the final result by leaving an uneven surface. Sealing the model also enhances the durability of the final item.

To seal a porous model, you will need the following materials:

• Sandpaper in various grits
• Sealant (epoxy resin, polyurethane, or wood sealer)
• Mixing cups and sticks
• Gloves and safety goggles
• A plastic sheet or newspaper

First, prepare your workspace by laying down a plastic sheet or newspaper to protect your work surface from spills. Put on your gloves and safety goggles to ensure your safety throughout the process.

Next, start by sanding the porous model thoroughly with sandpaper. Sanding helps open up the pores and prepares the item for sealing. After sanding, wipe away any dust and debris from the model's surface using a clean, dry cloth.

Then, choose an appropriate sealant based on the material of your model. For example, epoxy resin is ideal for a wide range of materials, including wood and ceramics, while polyurethane is suitable for wood surfaces, and wood sealer is specifically designed for wooden items.

Now, it's time to apply the sealant. Using a paintbrush, apply a thin layer of your chosen sealant evenly over the entire surface of the model. Ensure that the sealant penetrates the pores. Follow the manufacturer’s instructions for drying times.

Once the first coat of sealant is dry, lightly sand the surface again to remove any imperfections and prepare it for the second coat. Apply a second coat of sealant and let it dry thoroughly. This additional layer will further seal the pores and provide a smoother finish.

Now that your porous model is properly sealed, you can proceed with resin casting. However, it is important to test if your artwork needs to be sealed before applying the resin. To do this, ask yourself whether getting the surface wet will affect its appearance. If the answer is yes, you must seal your artwork before adding resin, as it will change colors and stain.

Additionally, you might want to seal your artwork if adding resin can disturb its surface. For example, lightweight items like beads, sand, and feathers can float in resin, and it may also disturb chalk and pastels. It is also recommended to seal your artwork if it is porous, as pores and holes can trap air, which will be released into the resin.

Cover your model with a light coat of a release agent

There are several options available when it comes to release agents. You can use resin mold release, which is specifically designed for this purpose and can be purchased online or at craft stores. Alternatively, you can use Silly Putty, which is an effective and inexpensive option as resin does not stick to it. If you are using a metal cookie cutter as your mold, you can also use release on a texture tile or rubber stamp to make unmolding easier.

When applying the release agent, you only need a light coat. Spray the release agent onto your model, ensuring that all surfaces are covered. Allow the release agent to dry completely before proceeding to the next step in the mold-making process.

By following this step and using a release agent, you will ensure that your resin mold can be easily removed from your model, preventing any damage to your creation and making the demolding process smooth and efficient.

Use two-part silicone mould putty

Two-part silicone mould putty is a great option for creating custom resin moulds with ease and precision. This type of putty usually comes in two different coloured putties that are combined in a 1:1 ratio to create the mould. The simplicity of this ratio makes it accessible to all skill levels. The putty is also versatile, allowing you to create intricate designs for resin, casting soap, wax, clay, or even food-safe moulds.

When using two-part silicone mould putty, it is important to work quickly as the curing time is usually around 20-25 minutes. This means that from mixing to moulding, the whole process can be completed in under half an hour. This makes it a great option for those who want to see their creative ideas come to life quickly.

To use two-part silicone mould putty, simply mix equal amounts of the two putties by hand until the colour is uniform. This usually takes less than a minute and there is no need to be precise with measurements. Once combined, quickly form the putty around the item you wish to replicate, ensuring that all air pockets are filled and the surface is even. Allow the putty to cure for the specified amount of time, which is usually around 20-25 minutes, and then remove the putty from the object. It is important to note that the putty should not be used for anything other than food once it has been used for resin or other non-food materials.

Build or secure an appropriate mould container

When creating a resin mould, it is important to build or secure an appropriate mould container. This can be done by using a variety of materials and methods. Here are some detailed instructions and tips to help you get started:

Firstly, it is important to choose the right materials for your mould container. The best substrates to use are melamine, medium-density fibreboard (MDF), or smooth plywood. You can also use EcoPoxy's Epoxy Mold Release Tape to clad the base and wall components of your mould. This will help prevent the resin from sticking and allow for easy removal once it has cured. Make sure to cover all the surfaces of the mould cavity with the tape and ensure it is completely flat and sealed.

If you are looking for a more flexible option, you can use empty plastic food containers as mould boxes. They are inexpensive and usually very flexible. However, if you choose to build your own mould box, make sure that all sides are leakproof. You can use a bead of silicone to seal the edges and create a butt joint where the walls meet the base of the mould.

Before pouring in the resin, it is crucial to prepare your workspace. Set up a worktable where you can easily access all parts of the inner mould cavity. Cover the table with a sheet of polyethylene (vapour barrier) for quick and easy cleanup. Tape the edges of the sheet securely to the table. Level the mould on the worktable and adjust it as necessary with wood shims, washers, or similar items.

Additionally, if your model is porous, such as wood, seal it with a mould-making material before using it. Otherwise, the mould material may stick, making it difficult to demould later. Cover your model with a light coat of a release agent before pouring in the mould material.

For those who prefer a simpler method, two-part silicone mould putty is a great option. It is easy to use and can create effective moulds. Simply mix equal amounts of the two differently coloured putties by hand until there are no colour swirls. Efficiently form the putty around the item you want to replicate, ensuring you fill all air pockets and even out the clay. Let the putty cure for the recommended time, and then remove it from the object. Your mould is now ready for casting!

By following these instructions and tips, you will be well on your way to building or securing an appropriate mould container for your resin project.

Frequently asked questions