How to make a simple alginate mold step by step

Learn to make simple molds with alginato and become a professional mold maker. You'll see it's a fast, easy process with excellent results.

Materials for making the mold

• Alginato

This is the perfect product for making molds of faces, hands and other body parts.

Alginato is used to capture specific details that are rarely achievable with any other product.

It's easy to use and has the property of hardening quickly. So in just a few moments you'll have a perfect mold, ready to cast. Though it can only be used once or twice, depending on the material.

It's a NON-toxic material, ideal for making body molds. It also contains no crystalline silica (a known carcinogen). It's easy to use, comfortable and clean.

• Escayola Exaduro

This is Exaduro white gypsum cement — a white gypsum cement that can be used in a variety of processes.

It works well for thin and delicate sections where high strength is required. It's ideal for solid and hollow molding methods for lamp bases, figurines, castings and molds in general.

It dries to a completely white color, making it perfect for incorporating pigments if you want different mold tones.

• Poliuretano PR-55

FEROPUR PR-55 polyurethane, part A and part B, is a two-component system used for casting work.

It is commonly used for reproducing pieces in silicona molds, negatives, scale models and prototypes.

The reaction speed of the component means a very short working time, and it also has low viscosity, which allows you to produce pieces in series using fewer molds.

Once the mixture has dried, it gives off no odor and is perfect for any fixing and machining application.

• Other items you'll need

You'll also need some additional materials to make your alginato mold easily.

You'll use disposable cups, warm water and latex gloves to protect your hands from aggressive and sensitizing components.

Video tutorial: how to make a simple mold with alginato

In this explanatory video we'll show you the step-by-step process for making an alginato mold.

Step-by-step guide to making a mold with alginato

We start with the first part, where we use the alginato

Next, we're going to mix the product. Put half a cup of water and half a cup of alginato powder.

A tip and recommendation: once used, make sure to store it properly.

We continue with the second part, where we make the mixture and the mold

The working time needed is 5 minutes, depending on the temperature of the water used. The colder it is, the longer it will take to dissolve.

The curing time is 8 minutes, with the same water temperature consideration applying.

Mix both the water and powder thoroughly with a small spatula until you get a smooth, homogeneous mass.

To create the mold, pour the mixture into a deep container. Dip your hand in and out a couple of times, removing the excess each time.

Keep your hand inside the cup with the mixture for 10 minutes.

Now proceed to demold by carefully removing your fingers. You'll see that the mold has taken the shape of your hand.

Next we move into the third phase: casting

To make the mixture, pour 100 grams of Exaduro plaster into 45 ml of water. Mix with a small spatula until you get a smooth, lump-free mass.

This will take 10 minutes of working time, depending on the water temperature, and a curing time of 25 to 35 minutes.

Now pour the Hydrokal White mixture into the hand mold we made earlier with alginato.

Once the mold is covered with the white cement plaster, mix part A and part B of the polyurethane.

It's important to use the same amount by weight and volume of both parts of FEROPUR PR-55.

In this case the process is very quick. You only need about 80 seconds of working time, depending on the ambient temperature, and 10 minutes of curing time.

You'll get an ivory-colored mixture with a Shore 75D hardness.

Pour the mixture of both polyurethane parts into the alginato mold. You'll immediately notice that the mixture will foam up due to the moisture.

Next, we recommend that to fill what remains of the mold, you wait for the collapse point to occur before pouring.

The collapse point is the exact moment when the mixture changes from a liquid to a solid state. That is precisely the moment when you need to pour into the mold.

The reaction of the PR-55 is thermally very intense, so you need to be careful when handling it. The speed of the reaction itself will depend on the amount of mixture, whether it is loaded or not, and the ambient temperature.

The final phase is demolding

Carefully remove the mold from the container and proceed to demold, leaving the hand and finger pieces in their original shape. This is where you can appreciate the foaming effect.

And just like that, you'll be making your alginato molds like a pro.

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