Making a mold for an artificial stone with your own hands: materials, technology

Until recently, only natural stone was used for facing the internal and external surfaces of buildings. Naturally, such a decoration because of the high cost of the material could not afford anyone. With the advent of artificial stone to the construction market, anyone can decorate their home with them. It is durable, inexpensive, visually no different from natural material, but most importantly, it can be made by yourself.

In this article, we'll talk about how to make a shape for an artificial stone with your own hands. We will also consider what materials can be used and what their characteristics are. But first let's figure it out, in what is an artificial stone.

Fake diamond

Natural building materials have always been expensive. This, first of all, is connected with their extraction and transportation. Enterprising merchants of building materials at one time solved this problem, replacing the stone with samples of similar sizes and textures made of construction mixtures.

Artificial stone is obtained by pouring in certain forms solutions based on gypsum or cement. Frozen samples are painted to give them a color of natural material. According to its physical properties, the artificial stone is in no way inferior to the natural stone, and in some cases even exceeds it. And believe me, it's often impossible for a professional to distinguish them visually.

Requirements for forms

Manufacture of artificial stone begins with the preparation of special forms (matrices), in which the solution will subsequently be poured on a certain basis. They are needed to give the future samples the size and texture of the natural material.

Form for the production of artificial stone should:

• Have high mechanical strength;
• Have good abrasion resistance;
• To resist the chemical effects of substances in the solution.

What Forms Are Made of

At home, the forms can be made from:

• Wood;
• Silicone;
• Polyurethane.

On sale are mostly plastic, rubber and polyurethane matrices. Consider the advantages and disadvantages of each of the listed materials.

Wooden molds

Making a mold for an artificial stone with your own hands made of wood is not the best option. The frame of the wooden matrix is assembled from boards, which are knocked down in a certain shape. The bottom of the matrix is also made of a board or a fibreboard. Naturally, there can be no question of any figured geometry of speech here.

The necessary texture is achieved either by using a special relief plastic substrate, or by using an old board with many defects as the bottom.

Advantages of wooden forms:

• Low cost;
• Simplicity in manufacturing.

Disadvantages of wooden forms:

• Poor tightness;
• Short service life;
• Impossibility of making figured products.

Silicone forms

Silicone molds for artificial stone have the greatest elasticity. This allows you to quickly and without unnecessary problems to remove the finished product from the matrix. For the production of molds, the most viscous silicone is used.

Advantages of silicone molds:

• High elasticity;
• Ideal as a mold for gypsum;
• Excellent tensile strength;
• Relatively inexpensive in self-manufacturing.

Disadvantages of silicone molds:

• Low chemical resistance;
• The formation of air bubbles in the manufacture of the matrix, as a result of which it may have defects.

Where to get the silicone?

Silicone molds for artificial stone are made of silicone, which today can be freely bought in construction stores. It is sold in a kit consisting of the most liquid silicone and hardener, changing the concentration of which can regulate the density of the resulting material. The cost of silicone in stores starts from a thousand rubles per kilogram, which, you will agree, is not so cheap, but if the form turns out, it will work out its triple.

You can save a little if you prepare silicone yourself from silicon dioxide (liquid glass) and acid hardener or ordinary alcohol. Such a silicone, of course, will not be of a special quality, however, as a last resort, it can be used to make a mold. It should be noted that the solution based on liquid glass very quickly thickens, so all work must be done very quickly.

Forms of polyurethane

Making a mold for an artificial stone with your own hands made of polyurethane is the most common and inexpensive option. Polyurethane has all the necessary properties to create an elastic and durable matrix that will last for many years. His best qualities are:

• High form stability;
• stability;
• Chemical resistance to oils, solvents, acids;
• Low glass transition temperature;
• Low inertia;
• High abrasion resistance.

In comparison with silicone, liquid polyurethane wins also due to high fluidity. This allows you to reproduce as accurately as possible the smallest textures that are present on the surfaces of natural stone.

What is polyurethane?

Polyurethane is a polymer material consisting of a polyol and an isocyanate. Varying the ratio of these components, you can get a hard, soft, flexible, or even foam material. This makes it completely universal for our purposes. Forms for gypsum, for example, it is better to make of soft polyurethane, for cement the rigid structure of a material is more suitable. On average, the polyurethane mold is capable of withstanding 1500-2000 castings, and high-quality factory matrices can withstand up to 4-5 thousand similar procedures.

Buy polyurethane can be in construction stores. It is also sold in a kit consisting of two components: working mass and hardener. The price per kilogram of polyurethane is 700-1000 rubles.

What else is needed?

The next question is how to properly shape, and what is needed for this, except for the material? First you need to get a master form, i.e. A sample of the stone that we would like to make. And of course, not one. Usually, making a mold for an artificial stone with your own hands means filling several initial samples. Master forms can be five and ten, depending on their size and the area of the frame.

Samples can be bought in the market or in the same building store, moreover, in one matrix you can place stones of different configurations and textures.

Next, we move on to the formwork, since it is possible to make a square shape for a stone only with its help. The frame is better made of laminated chipboard or MDF. It consists of four walls, a height that exceeds the top point of the largest master form by at least a few centimeters. The bottom of the formwork can be made from FEM or from the same laminated chipboard. The structure of the frame is assembled on self-tapping screws. If, as a result of the installation, crevices form between the walls of the formwork, we fill them with acrylic sealant.

When the material for the form and the samples of stones are bought, and the formwork is assembled, you can proceed directly to the manufacture of the matrix.

Correctly fix the master forms

Place the texture in the frame of the master form with the text side up so that there is at least one centimeter between them. Now, using the usual building silicone, fix each of them, applying a few drops on the bottom of the sample. Between the bottom of the formwork and the master forms there should be no crevices. Otherwise, silicone or polyurethane will fill them, and samples can not be extracted.

Making a mold for an artificial stone with your own hands

In order for the matrix to have the correct geometry, make sure that before casting the formwork can be installed on a flat horizontal surface. This, for example, can be a table or even a flat floor.

Now go to the preparation of the material for the matrix. The manufacture of a silicone mold for artificial stone (or polyurethane) begins with the mixing of components. Do this by strictly adhering to the proportions indicated in the manual. Any change will result in the form becoming too rigid, or, conversely, will not freeze at all. Mixing of components is carried out using a narrow spatula or a conventional mixer. Stir the solution, do not rush to pour it into the formwork. Give him a few minutes to settle, so that the air bubbles can rise to the surface. To make this process faster, a container with a solution can be heated with a hairdryer.

As long as the air bubbles come out, use a paint brush to lubricate the sample stones, as well as the unused surface of the bottom and the side walls with a separation compound, so that the mold can easily separate from the formwork. As a separator, conventional engine oil can be used, but in no case is it a test. Lubricate surfaces are recommended in several layers, so that the porous surfaces of the stone can be saturated with oil. If this is not done, the silicone or polyurethane will penetrate into the pores, as a result of which the surface of the mold will have corresponding flaws.

When this is done, fill the casing with an even layer of silicone or polyurethane solution, until the master forms are covered with a layer no thinner than one centimeter. Leave the future shape freeze for about a day. It is better if the congealing will take place at a temperature of +20 ° C.

We estimate the result of our work

After a day, the mold can be removed from the formwork. It is better to do this by preliminary dismantling the frame. So it will be easier to separate the matrix from both its walls and stones. If the shape in some places is too tight, poke it with a stationery knife. After separating the matrix, turn it upside down with the working surface, and let it dry for a few more hours. After wipe it with a clean cloth without strong pressure.

The first matrix, of course, can turn out to be imperfect. But do not worry too much, because experience is a gainful business, and in order to produce a sufficient amount of artificial stone, you will need at least five such forms.