How to make a silicone mold for pouring plaster. How to make silicone at home Liquid silicone for making molds

More and more craftsmen are showing a desire to try their hand at working with this relatively new material, but from the very first steps they are faced with difficulties, not knowing where to start, what silicone to use and how to handle it. Here I will try to summarize the main points, based on my own experience and information obtained from the Internet. I’ll say right away that I won’t tell you anything fundamentally new - everything that will be discussed is well known to professionals working with silicone, but I hope that the information collected in one place will help beginners overcome their first difficulties.

What silicones are needed for casting?

So, first of all, the silicone itself. When creating dolls, I use platinum-based compounds (two-component silicones) from Smooth-On made in the USA, so we will talk about them. To work, you will need two types of silicones: for casting the dolls themselves and for making the mold. There are not many of the first, primarily the Dragon Skin Series and Ecoflex Series. They have a high degree of elasticity and allow you to most realistically convey the effect of human flesh.

Silicones of each of these series have different technical characteristics: softness, lifetime (length of time when silicone remains fluid), hardening time, viscosity, etc. What kind of silicone is best to use when creating dolls? I can’t say anything specific here - it all depends on the master’s ultimate goal. In my opinion, it is best to follow the path of experimentation, trying different series in order to find in practice the very, only material that allows you to achieve the desired effect.

Silicones from the Dragon Skin Series and Ecoflex Series are colorless and translucent, so to obtain a realistic doll color they must be colored using special Silc Pig pigments.

The second type of silicones is used to make the mold. Be careful - Platinum-based silicones can only be cast into molds made from platinum-containing silicone. Silicones with a tin catalyst cannot be used. Otherwise, the casting will not harden. Silicones intended for mold removal have less elasticity, greater hardness, and are usually brightly colored or transparent. The bright color of one of the components allows you to evenly mix components A and B before pouring, and the transparent ones allow you to see the model in the mold (this is convenient if the mold is cast as a whole and then cut into parts). Silicones intended for mold removal include such series as: E-Series, Mold Star Series, Equinox Series, Rebound Series, etc.

The mold can be made by pouring, or by gradually applying layers of silicone with a brush. The first method is simpler and faster, but requires more silicone consumption. The second one is more labor-intensive, and it also requires various additional materials. You can clearly see the process of creating a “spread” form on the official video of the company:

A little about forms

The finished silicone mold remains elastic, this is its absolute advantage, but we must not forget that it can be easily deformed, so it must be placed in a special protective casing cast from ordinary plaster.

Before pouring silicone into a silicone mold, you must use a special release agent, Ease Release, otherwise the mold and the casting will stick tightly together. The separator layer must be thoroughly dried, since in some cases it prevents the silicone cast from completely hardening.

Molds for casting dolls can be made not only from silicone, but also from plaster. It is advisable to use special dental plaster for this purpose, such as Fuji Rock, which has increased strength, perfectly conveys small relief details and dries fairly quickly. Compared to silicone molds, gypsum molds do not require the use of a release agent and absorb excess silicone oil during the casting process. However, plaster molds also have significant drawbacks - the master model is almost impossible to remove from the plaster without damage, the molds open with great difficulty and quite quickly become loose, losing the accuracy of the alignment of the halves. Also, compared to silicone, a plaster mold has to be made from more parts, which increases the number of seams on the finished casting.

Basic rules for working with silicone

So, we’ve sorted out the materials for casting, now let’s talk about the process itself. To avoid defects and failures when working with silicone, you must follow two golden rules that make the life of the master much easier:

1. Always strictly and pedantically follow instructions, avoiding any amateur activities.
2. Always test new materials that come into contact with silicone for compatibility.

For work, it is advisable to purchase a vacuum chamber with a pump that pumps out air from the mixture before pouring. Some types of silicones can be used without prior degassing, however, the risk that air bubbles will remain in the frozen mass is quite high.

It’s also a good idea to have an oven or drying cabinet for post-curing finished products. Silicone that has undergone heat treatment quickly acquires the physical and chemical properties declared by the manufacturer. I would not risk heating products in an oven intended for food products, despite the fact that platinum-based silicones are considered non-toxic materials.

I would like to note that making silicone dolls requires significant financial expenses, but you cannot save on materials and equipment by looking for cheap analogues and doing amateur work - the result of such experiments is usually disastrous and leads to inevitable damage to castings and molds.

When working with silicone, you should only wear vinyl gloves; latex gloves cannot be used.

The casting room must be heated; the temperature in it should not fall below 22-23 degrees. The required temperature regime is one of the most important factors - at temperatures below 18 degrees, silicone may simply not harden, and higher air temperatures slightly reduce the life time of the finished silicone mixture.

But you can’t store silicone in the heat. The material has a limited shelf life, which is reduced by increasing temperature. An open can must be used quickly, since contact with the environment can also affect its properties. The algorithm for working with silicone should be as follows: take the jars of silicone out of a cool place, wait for it to warm up to the required 23 degrees, thoroughly mix the contents of each jar, combine components A and B in exact proportions, subject the finished mixture to degassing, pour into the mold and return the remaining silicone to the cold room.

In general, it should be remembered that silicone is a very capricious material that does not allow liberties in handling.

The vagaries of silicone

In principle, the process of making silicone castings is elementary, but this simplicity is deceptive. Silicone constantly presents unpleasant surprises, preventing the master from relaxing and making mistakes. The main danger for uncured silicone is inhibition (poisoning) by various substances incompatible with it. The most formidable and at the same time the most common “enemy” of silicone is plasticine containing sulfur. To work, you need to buy only plasticines marked Sulfur Free, such as Monster Clay or Chavant. It is better not to keep questionable plasticines in the workshop at all - even accidentally touching a sulfur-containing material with your hand can “infect” the silicone mold.

The second “enemy” of silicone is latex. Do not use latex gloves, syringes with rubber nozzles on pistons, or any other instruments that have latex parts in their design.

Use wooden sticks with great care to stir the mixture. Some types of silicone do not tolerate contact with wood and may be inhibited. To protect yourself from unpleasant surprises, it is advisable to mix the silicone with metal stirrers.

Freshly cured polyesters, epoxy and polyurethane rubbers are also dangerous. As I already wrote above, before using any new material in your work, you need to test it by filling it with a small portion of silicone. If the mixture completely hardens in the usual time allotted for complete polymerization, and the surface of the silicone is not sticky, we can assume that the new material has successfully passed the exam and can be used in further work.

That's basically all I wanted to tell you about the techniques of working with silicone. I myself have often made mistakes, experienced many unpleasant moments, and I hope that this hard-won experience will help novice craftsmen not step on the painfully familiar old rake, and save nerves, time and money. Good luck with your creativity!

In construction, molds are often used to produce various products and products. The most basic of them are polyurethane and silicone. It is possible to pour not only gypsum and concrete into them, they are also used to make artificial stone. All this can be done with your own hands. Even if it seems that you need to have some knowledge, this is a misconception. This article will tell you in detail how to make a polyurethane mold, a mold for pouring plaster, silicone, a mold for pouring plaster, concrete. He will also teach you how to make your own matrix for producing molds from silicone or polyurethane. The most important thing is to understand how to build, according to the rules, a practical template for a matrix that is suitable for materials such as polyurethane, molded plastic and silicone.

Unnatural stone, at the present time, is a good, profitable business. To open your own business, with the prospect of further growth, you do not need a lot of cash investment. Unnatural stone can be easily made with your own hands using all technologies. But first, it is important to have a room with a suitable temperature so that work can be carried out year-round.

The production of unnatural stone requires good, high-quality forms, which cannot be obtained without a matrix. The manufacture of a matrix sample must be approached very responsibly, because the strength of the final product depends on it.

Some people consider the process of making artificial decorative stone at home impossible. But thanks to desire and desire, everything becomes possible. It is better to have good quality materials and combine them with some additives. For example, the setting time of silicone and its fluidity can be adjusted using catalysts.

It is quite achievable to produce a matrix for the production of silicone and polyurethane molds with your own hands, with the help of which the casting process itself will be possible. To make a matrix, you need to purchase or find a sample from which it will be possible to copy or produce forms identical to the presented model.

If it comes to non-natural stone, then in these circumstances the sample must be of perfect geometric shape, without cracks and possible deformed corners. Most often, a variety of raw materials are used to produce polyurethane forms, to create non-natural stone or a sample for the production of stone forms. For example, plaster, drywall or foam. Sometimes they come to the method of copying from non-natural or gypsum stone, but the ideal option is considered to be a sample made from natural stone.

To do this, take a natural stone, cut it into thin plates (about 1 cm) and glue it together with glue. The stone must acquire an impeccable geometry in all respects. If there are uneven sides or protrusions, then a grinder and a machine will come to the rescue, which will level or remove all unnecessary parts. The finished stone with any irregularities removed is ready for gluing.

Stage 2. Production of a matrix for creating molds from polyurethane or silicone, formoplast, liquid plastic

The created model needs to be glued onto some kind of base in order to make a matrix from it. An excellent option would be to use chipboard as a stand. The finished model must be glued to the chipboard using silicone sealant. But this can only be done on the glossy side of the stand.

For gluing, silicone sealant is taken and applied to the back side of the prepared model. All edges and corners are thoroughly covered. When turning the stone over, press it firmly against the chipboard tray. Next, use a spatula to carefully go over the joints, making sure that all air bubbles disappear. There is no need for excess air when filling with polyurethane or silicone. After covering, the workpiece should be left until completely dry. After this, it is time to build the sides for the matrix. The height of the walls must exceed the height of the glued stone. The material for this can be plastic, steel or duralumin corners. At a distance of approximately 1.5 cm from the finished model, the corners need to be screwed to the chipboard around the entire perimeter using screws.

It is important, after screwing, to carefully go through all joints and corners with silicone sealant, once again double-checking the reliability and tightness of the structure. Otherwise, fluid polyurethane or silicone, which has the ability to penetrate even the smallest cracks, will leak out of the matrix. In order for all the material to dry thoroughly, it is better to leave the matrix to dry (about 12 hours). It is recommended to use silicone sealant for aquariums. Its main feature is the elimination of shrinkage or cracks that often appear after drying. A matrix treated with such a sealant will last for many years without problems.

After making sure that the almost finished matrix is ​​completely dry, the next step is to lubricate it with a specialized separator. This mixture can be purchased at any construction stores. Almost all of it has a wax base, and differs only in the manufacturers. The best separator is English. After application, it dries completely, dissipates, and after just a few hours, polyurethane, formoplast, gypsum or silicone can be poured into the prepared matrix. Any compositions used to create forms are suitable.

Stage 3. The rule for pouring polyurethane into the matrix when making a polyurethane mold

Firstly, you should decide on the choice of the substance itself. For example, if we are talking about non-natural stone, then it would be correct to make molds from polyurethane. And so, it is allowed to fill with any material adapted for such work. Large factories and enterprises use specialized equipment that makes the task easier. But you can fill the mold with your own labor. How to do this correctly?

There are unnatural stones with different numbers of angles. This stone looks beautiful and is very popular. For him, polyurethane form is the best option. It is convenient and practical, easy to clean and will not create any unwanted errors. The pouring process is a delicate matter and here you need a table or some other object that will be clearly level. Ready-made silicone or polyurethane (manufacturers themselves write how to prepare it on the packaging of the material) should be poured in in a slow stream, avoiding the ingress and formation of air bubbles. In this case, it is important to tilt the matrix slightly to one side.

When the solution reaches the bottom wall of the matrix, the entire structure can be lowered and the pouring of material can continue. Left for a day, the matrix will harden and take a suitable shape.
Once completely dry, the matrix is ​​ready for disassembly. It is too early to use it for the production of artificial stone. For better fixation, it is advisable to leave the product in a warm place for some time. This is necessary so that the form has no unevenness on the walls or surface. This is especially true for polyurethane, since this material has memory and, if you bend it and leave it like that for a short time, it will remain that way. By standing in a warm room, such forms will have a longer service life, regardless of what solution they will be filled with.

Also read:

Silicone products cover many fields, from medicine to arts and crafts. This organosilicon material does not cause allergies, therefore it is safe to work with; thanks to this property, it is used both in medicine and for creativity. Due to its tightness, it is also used in construction.

We recommend purchasing silicone products from trusted manufacturers, but you can also make silicone rubber at home, which is a type of silicone, a wide class of organic chemicals. This substance, another name for which is polydiethylsiloxane, resembles the touch and consistency of rubber after hardening, is just as elastic and resistant to damage, but unlike rubber, it is devoid of a pungent odor.

For creativity, it is best to choose this material, because unlike plasticine, it does not undergo deformation after hardening, does not require baking and does not emit toxic substances like polymer and has much greater strength than products made from ordinary clay.

How to make a silicone product with your own hands?

1. To do this, you will need to prepare reagents available at home - liquid glass and ethyl alcohol. Liquid glass can be purchased at any car care supply store, and ethyl alcohol can be purchased at a pharmacy. Also take care to protect the skin of your hands - be sure to protect them by wearing latex or rubber gloves. You should also take such ordinary measures as ensuring the cleanliness of the work area - keep in mind that liquid silicone, after hardening, is unlikely to be easily washed off the table, so cover the work surface with newspaper or oilcloth.
2. Then you need to prepare working materials. When choosing a container, it is advisable to take dishes made of plastic, because liquid glass, due to its composition, often enters into a chemical reaction with many metals, including aluminum. Reagents must be poured into the container in equal proportions, that is, 1:1. Their quantity depends on how much silicone you want to get, because the more liquid glass and alcohol you take, the more material you get. After the liquid glass and ethyl alcohol are in the same container, mix them until a homogeneous dense mass is obtained using a spoon, wooden stick or any other tool that is convenient for you. If necessary, you can add any dye to the resulting mass to give it a different color. You can also add glitter or even two dyes at once to create a “marbled” color of the substance and product in the future. Over time, it will thicken, become plastic and dense, like plasticine.
3. And when the substance becomes thick and dense, you can begin to sculpt the figure. Give it the required shape. This will be easy to do, because the resulting substance is plastic and pliable. Upon completion of sculpting, let the figure harden, leaving it for several hours in a ventilated area. After hardening, the product will be elastic, will no longer be subject to deformation, and it will feel like rubber to the touch.
4. If you need to make a copy of an item or make several identical products, then it is best to use ready-made liquid silicone, which you can find in a specialized hardware store. Its difference from its homemade counterpart is that, thanks to the substances included in its composition, it hardens much more slowly. This makes it easier to use for casting a figure using molds.

   If you want to make a copy of the figurine, you should make a mold from sculptural plasticine. It’s better to take it, because it hardens better when it cools than regular children’s one.

   Take any container and put plasticine into it in small pieces, tightly attaching them to each other. It is recommended to knead it well and make sure that there are no holes or cracks in your homemade mold, this will help prevent silicone from leaking from it. When the entire container is tightly filled with a homogeneous plasticine mass, place the object into it, pressing it into the plasticine. After this, carefully remove the figure and fill the container with silicone.

5. After the silicone has hardened, carefully shake out the plasticine with the figure from the container and remove it from it.

If the plasticine was not seriously damaged, then you can restore the mold and use it again. This method will allow you to easily reproduce copies of different figures.

After this, you can decorate the figurine to your taste, add rhinestones, sequins, and even paint the product with gouache or acrylic if necessary.

Ready! So, using one of these methods, you can create your own masterpiece of decorative and applied art using silicone, using it as a material for your creativity. You can go beyond ordinary modeling, because in addition to it and casting the figure, you can pour liquid silicone into a pastry bag and squeeze out anything figuratively, use cookie molds or children's sand molds, and also work only with your hands, which is of course useful for adults, so for children.

Such creativity does not require large expenditures, and sculpting and a variety of color dye palettes provide ample opportunities for creating both ordinary figurines and, if desired, even jewelry. After all, jewelry from such material is no less easy to make, be it an intricate pendant, original earrings, or unique beads from which you will later create a bracelet or necklace.

Today we will create a complex silicone mold for reusable castings.

To do this, you will have to dive into some interesting subtleties. Taking impressions opens up enormous opportunities for all kinds of homemade products. Usually, to make a cast of a figure, you need to make two halves. One half is covered with sculptural plasticine, and the second is filled with silicone.

Then remove the plasticine and pour silicone into the free half again. This way you can make impressions of excellent quality.

But what to do if the entire figure is made of sculptural plasticine.

No, it’s not a tree, not a mushroom, or even broccoli. This is a model of an atomic explosion from the largest bomb in human history, AN602.

The author tried to make this model more or less similar in shape to that very explosion. We will make a cast of it. To then cast it from epoxy.

Everyone loves explosions and it's nice to have such a small glowing atomic explosion on your desk.

Materials and tools:
1. Silicone
2. Vaseline
3. A couple of boards
4. Screwdriver and screws
5. Knife
6. Pliers
7. Plastic caps
8. Sculptural plasticine

When taking an impression, it is very important to think about how the model will be positioned, so that when pouring silicone it does not turn out to be unable to fill some areas. Or in the future, when you pour plastic, epoxy, gypsum, wax or anything else into the mold, there should also not be a place where air cavities may appear, into which the composition simply cannot enter.

For this purpose, the author bought a bucket of cheap Chinese silicone and, probably, this is the cheapest silicone that exists. Hardness thirty. That is, it seems like medium hardness. Just what you need for collapsible forms.

The layer of silicone around the figure should be at least two and a half centimeters.

You'll have to make a box of the right size.

All seams must be covered with plasticine, otherwise it will leak.

The silicone won't leak much, but it's still unpleasant. At the top the model is much narrower than at the base. You can’t leave it like this, otherwise a whole kilogram of precious silicone will be lost. Therefore, the filling had to be made from the bars. Unused corners and nooks and crannies can also be covered with plasticine to save money.

To make it easier to peel the silicone from the wood, all walls must be thoroughly treated with Vaseline. Where would we be without him?

In order to secure the model inside the formwork we will use self-tapping screws. Plasticine
sculptural, not too soft and holds its shape well. So, in principle, it should work. In order to know to what height to fill and not guess later whether you poured a lot or a little, you need to roughly mark the desired level with a pencil.

And now there's silicone. It comes with a tin hardener, and sometimes with a platinum hardener. Tin is naturally cheaper and more unpretentious.

There are rumors that silicone does not interact well with plasticine and may not polymerize. In this case, the plasticine begins to melt and the model can then be thrown away. To save yourself the hassle and not worry about this, just pour a little silicone into a mold made of the same plasticine as your model. After some time, see what happens. Most likely everything will be fine and there will be no mistakes.

If the silicone does not want to harden, then you need to cover the plasticine with a layer of Vaseline. Or, as an option, purchase special aerosol separators. They are sold in the same place where silicone is sold.

Having estimated the required volume of silicone, taking into account the fact that it will also spread throughout the container when stirred, the author decided to prepare one and a half kilos. When mixing with the hardener, you need to mix very carefully, by hand, so as not to create bubbles in the silicone. Usually, even if bubbles appear, they basically come out of the mixture well. But not in our case. Chinese silicone snatches air just like before death. Even with gentle stirring, there are a bunch of bubbles inside. The author tried to do degassing using a small vacuum pump.

The process went on, bubbles came out. But this volume is too large for such a pump, and silicone cannot be kept idle for a long time. It needs to pour. You need to pour slowly, carefully, so as not to touch the model with the stream. Otherwise, you will have to cut off excess silicone from it before pouring the second half.

Now you need to make the locks. The form will be collapsible, which means it must fit together clearly. The author suggests using these plastic caps.

Plastic is lighter than silicone, but not by much. You need to experiment before pouring. Mix a little silicone and choose something suitable that will not sink completely and will be easy to remove. We press plasticine inside the caps to make them heavier.

But not so much that they sink completely, but so that they stick out slightly from the silicone. You need to place such locks as often as possible. There won't be any extra ones - that's for sure.

After the silicone has completely hardened, you can pull out the caps and cut off any protruding burrs.

When pouring the second half, silicone will be poured into the resulting recesses and you will get locks that will help to accurately join the two halves.

Next, lubricate the surface of the silicone with Vaseline so that the next layer does not stick to it. We finally close the formwork with the last board. Then pour silicone to the mark that you previously marked with a pencil.

In order for the silicone to better wet the model and release gases, you can lightly vibrate it with a spoon.

Now you need to wait for the second half to completely harden. This should take about 16 hours at room temperature. In general, this particular silicone sets within an hour, but it gains full hardness in almost a day.

The silicone remaining in the container polymerized, but not completely. As usual, it is not possible to mix the silicone with the hardener well at the bottom and in the corners. It remains forever a sticky mess.

Therefore, it is better to use disposable utensils for kneading. Or the one you don’t feel sorry for. But if you happen to mix silicone in the favorite cup of your mother, wife, or God forbid mother-in-law, then you will definitely have to wash it. Basically, just like your hands. Regular soap, to be honest, does a terrible job. More precisely, it does not wash off silicone from your hands at all. Most silicone from dishes and hands can be wiped off with rags. And hand cleaning paste works well with the remaining silicone.

This paste is something like concentrated soap mixed with a fine abrasive. It scrapes off all the silicone and prevents it from sticking again. After wiping with the cleaning paste, simply rinse off all the silicone with water. And no solvents or other cleaning agents are needed.

Well, you can disassemble this miracle box. Any excess protruding pieces are immediately cut off. You can see how the silicone leaked through a small gap.

Even after smearing with Vaseline, the pieces of wood do not want to come off. You have to make an effort to separate the silicone. The halves stuck together quite strongly, but they were still served. Plasticine, even without Vaseline treatment, does not stick to silicone at all. The model turned out to be absolutely undamaged. Except for minor mechanical issues that are easy to fix. This method of making copies turned out to be very gentle.

Silicone is a soft and pliable material that is used to make molds. There is nothing difficult about making something like silicone at home from improvised materials.

How to make silicone at home - method 1

• White Spirit;
• pipette, spoon, plastic glass;
• acrylic paint;
• liquid glycerin;
• silicone sealant.

All components are mixed in the following proportions: for 30 grams of sealant, take 150 grams of white spirit, 1 drop of paint and 3 drops of glycerin.

• Place the sealant in a plastic cup.
• Add the specified amount of paint and glycerin. If you don’t have a pipette at hand, you can use a straw.
• Add white spirit.
• Stir the solution until it is will not become homogeneous (paints will not should be visible).
• Ready. You now have about 5 hours to use this silicone before it hardens.

How to make silicone at home - method 2

To make silicone you will need the following components:

• ethanol;
• liquid glass.

Sequence of actions when preparing silicone:

• You need to prepare a suitable container in advance and create working conditions. The container can be any. Pour ethyl alcohol and liquid glass into it in equal proportions. Mix the ingredients with any tool (wooden stick or spoon). When the solution begins to thicken, it can be brought to the desired state simply by rubbing it with your hand. A white dense mass forms in the container, which after some time will become similar to plasticine.
• The required shape needs to be sculpted only when the mass begins to harden. There will be no problems with this, since the substance will be plastic and soft, similar to rubber. Once you have the desired shape, set it aside until it hardens completely. The silicone will harden and the mold will become less susceptible to deformation.

How to make silicone at home - method 3

Add 3 tablespoons of silicone sealant and the same amount of potato starch to a plastic cup. The resulting solution must be stirred for 7-10 minutes. When the silicone begins to easily come off your hands and knead well, you can begin making the mold, which is very simple.

How to make silicone at home - method 4

Buy several packets of gelatin and the same number of vials of glycerin. The quantity depends on the size of the mold. Everything is mixed “by eye”, approximately 50/50. Try not to violate the proportions: if there is little glycerin, the mixture will be liquid, and if there is too much, it will stick like glue. 55/50 is the best option.

All this needs to be heated in a water bath, but an ordinary candle will do. Your main task is to prevent the gelatin from boiling. Otherwise it will start to stink a lot. You need to heat and stir the substance for about 10 minutes until you get a homogeneous mixture.

How to make silicone at home - copying an object

Prepare a mold that is slightly larger than the item you are copying. Pour some silicone into the bottom and leave to harden. This will be the basis for the item. The thickness should be at least 1 centimeter so that the “rubber” reliably envelops the object from all sides. If the mold is thin, it will tear when the prototype is removed or will not hold its shape at all.

Partially dip the prototype into a bowl of gelatin to remove any air bubbles. Quickly transfer the item and place it on the bottom of the mold, gluing it down. Fill the mold completely with silicone. Homemade resin from the 4th method hardens very quickly - before our eyes. Immediately after cooling, disassemble the mold. Make a cut and carefully remove the prototype.

Mix and pour epoxy resin into the mold. The frozen casting is quite difficult to remove, so you will have to cut the silicone in a circle or completely tear it apart.

Getting rid of silicone

Wash the surface using any detergent designed for grease. You may also need a piece of pumice and a knife to get rid of the silicone. The hardened silicone is cleaned off with a knife, and all its remnants are removed with pumice. This method is only relevant for non-scratch surfaces.