There are many similarities when making a flexible silicone or polyurethane mold. This video shows step by step the technology for creating a simple two-part mold. This video is a translation with comments from the English version from TAP Plastics.
Here, 2-component polyurethane was used to make the molds. One of the differences between polyurethane for molds and silicone is that everything sticks tightly to polyurethane, so careful comprehensive lubrication is necessary. Whereas practically nothing sticks to silicone and you can either use nothing at all or use wax lubricants, soap solution, or Vaseline. When working with silicone, it is recommended to lubricate porous models (plaster, clay, etc.).
Stages of work:
- We make formwork around the model. It can be made from any hard material: fiberglass, planks, remnants of chipboard, children's Lego. Or choose a ready-made container of suitable size.
- We connect all the formwork parts, sealing all the cracks with hot melt glue.
- We take sculptural plasticine (children's clay is not suitable), put it almost halfway into the container. The surface of the plasticine should be smooth, without cracks. Place the model in plasticine.
- We make holes in the plasticine with a pencil - “locks”, so that the 2 parts of the mold fit into one another, and there is no displacement of them when casting the model.
- Now we calculate the required amount of silicone or polyurethane. We fill in any bulk material (cereals, salt) and measure it in a measuring container.
- Lubricate the surface of the model with a release agent (you can use wax or soap solution). For silicone molds, you cannot use silicone grease, silicone will stick to silicone!
- Mix the calculated amount of part A of the base and hardener.
- We wait for curing and remove the plasticine.
- Again, lubricate the surface of the mold, including the locks. And we prepare the molding material. Pour in and wait for complete curing.
- We separate the 2 parts of the form and take out the master model. The form is ready.
- To replicate, securely fasten the two parts of the mold and fill in the selected model material.
Manufacturing technology of two-part silicone or polyurethane molds
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http://www.youtube.com/user/SiliconeFormoplast- master classes How to make silicone molds
Silicone molds are used for casting standard products. Silicone is a budget-friendly and convenient material for these purposes: it can withstand heavy loads and temperature differences, and is compatible with many materials. The production of silicone molds is carried out using a simple technology, which is characterized by low technological requirements.
The main goal when making a mold is to suit the future process. It must meet production requirements in terms of: shape, technology used, material characteristics.
Production stages
The production technology consists of several stages:
- preparing the model if necessary. At this stage, an analysis of the future technological process is carried out and a material for the matrix is selected - a filling compound for molds;
- the prototype completely reproduces the shape of the future model, taking into account the location of fasteners, protrusions, and sprues. Technological grooves and holes are also displayed;
- the next step is the preparation of formwork and embeds. The formwork needs to be covered with sealant and the prototype fixed. If necessary, the outside of the model is coated with a separation compound;
- Next, the material for filling is prepared. Silicone is mixed with the addition of special compounds. Then degassing is performed by vacuuming;
- The next step is to directly pour the silicone into the mold. The process is carried out under vacuum conditions so that there are no air bubbles left in the future form;
- Then polymerization or hardening of the material occurs. Depending on the additives used and the thickness, it lasts from a day to a week;
- Next, the resulting product is cleaned, followed by drying.
Types of silicone
When making molds, the following types of silicone are used, which are selected depending on needs:
- anti-allergenic;
- resistant to temperature changes;
- especially durable (for example, tin-based silicone paste) and others.
Supplements
Additives are used to impart certain technological properties to the form. They are selected depending on the final goal. If it is necessary to add color to the form, a pigmented additive is used. There are also compositions that:
- contain a hardener and help accelerate the hardening process;
- increase the viscosity of the material, which allows it to be applied to the model with a brush;
- increase the strength of the material and others.
The main requirements for production are the provision of ventilation and the presence of protective rubber gloves on the hands of the worker.
Silicone is a high-quality material for creating flexible injection molds. Technology for making silicone molds yourself
How to make your own molds from silicone and how to make your own products from epoxy resin
Silicone hardens without shrinking at room temperature and forms silicone rubber. Two-component liquid silicone for mold making, silicone molds are suitable for epoxy resin casting production. How to make your own silicone mold for casting an epoxy resin product at home. How to make a mold for plaster or for casting epoxy resin from poured molding silicone at home without having any experience in making molds.
Technology for self-production of silicone molds from elastic two-component silicone.
Making silicone molds at home and then pouring epoxy into a silicone mold. In this topic, the production of silicone molds for making products from epoxy resin, we will try to master the simplest technology for independent production of silicone molds for pouring epoxy products. Two-component silicone is used for casting molds and making impressions. I offer you a free master class on making products from epoxy resin. Technology for making silicone molds and methods for making products from epoxy resin.
All about raw materials for self-production of molds at home.
How to choose a material for making molds and castings from gypsum, concrete, polymer concrete, polymer resins. In addition, the production of molds and sculptures can become an independent profitable business. How to choose a material for making an elastic mold for castings from plaster or other materials. Casting in silicone molds using the example of making a simple product from epoxy resin.
Silicone compounds and rubbers are easily processed into molds even at home and do not require any additional equipment, as they can be poured by hand. After carefully reading the step-by-step instructions, you can easily make injection molds from silicone yourself. The same molds, made on your own, will cost about half as much as you can buy them, in addition, you will be able to make any mold yourself and will not depend on mold manufacturers and on the assortment that mold manufacturers offer you, and you will be able to make the assortment of molds yourself for products that are not on the market, so you will have absolutely no competition in your assortment.
Copying products, making your own mold from silicone and pouring epoxy resin into a mold is something that you can do yourself at home or in an industrial environment by carefully studying my step-by-step lesson on making silicone molds and mastering the methods and technology of pouring epoxy resin.
The technique presented to your attention is a detailed description of this technology for copying products.
Action 1. As an example, consider copying a simple product. We will cast this part from epoxy resin into a detachable silicone mold consisting of two parts.
Step 2. To apply the described technology for making silicone molds, we will need the following materials: two-component silicone for self-production of the mold and epoxy resin for pouring into the mold for making the product.
Action 3. Silicone. This is the material from which the casting mold will be made. Although common and inexpensive silicone sealant is quite suitable for this purpose, it is much easier and more convenient to use two-component silicone, specifically designed for making molds. In the example below, we will use just such silicone from Pentasil; any other two-component potting silicone will do.
Action 4. Epoxy resin. There are a great variety of such resins on the market, and most likely many of them will be suitable for our casting. The main requirement for the resin is that the polymerization time should not be too short. In particular, I focused on a product called Finishing Resin for our product example. This resin after polymerization is quite elastic, and its physical properties resemble polyurethane resin.
Action 5. Release agent. If the mold material is two-component silicone or two-component polyurethane, a separating layer will only be needed to separate the halves of the mold. There are many release products specifically designed for this purpose, usually in the form of a wax-based aerosol, but if you do not yet have the opportunity to find such a release, regular petroleum jelly or melted candle wax will work just fine.
Action 6. Plasticine. It will serve us as the main building material. Before you start making the mold, you should check the selected materials for consistency with each other. If you neglect this stage, you may not only not receive a copy, but also lose the original. First, make sure that the silicone you choose, once cured, can be easily removed from a surface made of the same material as the part being copied. If this is not the case, the part to be copied will have to be coated with a release layer, or a different silicone should be used. Second, make sure that the cured epoxy resin releases well from the silicone and that you are satisfied with the physical properties of the cured resin.
Step 7. Making silicone molds. To begin, apply an even layer of plasticine onto a flat, solid base (I use a CD for this purpose) and lightly press the part to be copied into it.
Action 8. If the part is relatively flat, it can be pressed into the plasticine to the level where the border of half of the future form passes. In the case of a more voluminous part, instead of pressing the part to its full depth, we will apply another layer of plasticine around the perimeter of the part.
Step 9. After this, you need to walk around the perimeter of the part and press the plasticine against its wall, thus forming a clear boundary. To do this, I use improvised devices made from matches and toothpicks coated with silicone sealant. Since plasticine does not stick to silicone at all, it is very convenient to process it with this particular material. Please note that on the future casting, a small seam will form at the place where the mold halves meet, so the location of the border must be chosen in such a way that this seam can be removed without damaging the parts around it. 
Step 10. It is important to make sure that the plasticine fits tightly to the part being copied, so that the silicone cannot leak under it when casting the mold.
Step 11. Now we will make the walls of the future container, for which the easiest way is to use the same plasticine. The distance between the wall and the part should be 5-7 mm, and by the same amount the wall should exceed the highest point of the part being copied. The junction of the wall and the floor of the container is leveled using the same devices coated with silicone.
Step 12. After this, it’s worth making several small depressions in the floor of our container. They will serve as locks to prevent the halves of the future form from moving.
Step 13. So, the container is ready to fill with silicone. The silicone we are currently working with to create our product consists of two components: a thick white mass, reminiscent of condensed milk in consistency, and a dark blue liquid catalyst; there are catalysts of different colors, which must be mixed in a ratio of 10:1 (in the instructions not specified by weight or volume; I use scales for dosage). The bright color of the catalyst helps to ensure complete mixing of the components - the finished mixture should have an absolutely uniform blue color. Avoid contact of silicone and especially catalyst with skin. It is advisable to work with gloves (this, by the way, also applies to epoxy resin).
Step 14. Pour the resulting mixture into a plasticine container with the part to be copied. This should be done slowly, in a thin stream, and try to pour the silicone into the far corner of the container, and not onto the part, so that the silicone flows around it gradually, from below, without forming voids and the air has time to come out, otherwise it will end up in the form of a hole. There is no need to rush - this silicone remains fluid for almost an hour, but we must remember that silicones generally have fluidity, that is, a lifetime of 10 minutes. Once pouring is complete, the container should be left alone until the silicone has completely cured.
Step 15. After the silicone has hardened, remove all the plasticine. This must be done very carefully, so that the copied part remains in the silicone, from which it is very easily separated. First, carefully remove the side walls, then remove the floor.
Step 16. As a result, we have the finished first half of the form with the copied part in it. If there are traces of plasticine left on the form or part, they must be carefully removed, again not allowing the part to separate from the silicone.
Step 17. Place the finished half on the same disk and build plasticine walls around it, the height of which is 5 mm higher than the highest point of the part.
Step 18. Using the method and tools described above, we will achieve a more or less airtight joint between the mold and the plasticine walls (this is not so easy, because plasticine reluctantly sticks to the silicone mold, but absolute tightness is not so important here).
Step 19. Be sure to cover the surface of the first half of the mold with a separating layer of Vaseline, or apply a separator or paraffin in order to prevent the halves of the mold from sticking together (the silicone sticks tightly to itself). To do this, you can use a brush, applying a very thin layer of Vaseline, and only on the silicone, and not on the part to be copied.
Step 20. The container for the second half of the mold is ready. Preparation and pouring of silicone is carried out in the same way as for the first half. All you have to do is be patient.
Step 21. After the silicone has cured, remove the mold from the disk and remove the plasticine walls.
Step 22. Now we have to separate the two halves of the finished silicone mold. Despite the separating layer, the halves may be stuck together at some points, so some force will be required to separate them. It is important not to damage the copied part located inside.
Step 23. So, our self-made mold from two-component silicone is ready!
Action 24.Casting a part from epoxy resin
First, let's prepare the epoxy resin. The components of epoxy resin are usually mixed in a 1:1 ratio, and it is advisable to adhere to this ratio as closely as possible. For resin, at least the one we took for production training, scales are not suitable; the components have different densities, so it is better to use special measuring cups. Lately I've been adding a third ingredient to the resin: a small drop of a special coloring pigment (a mixture of black and white). In this case, the casting is not translucent, but has a more familiar gray color.
Step 25. Mix the epoxy resin thoroughly, not only in the center, but also along the edges of the container, but at the same time carefully, trying to introduce as few air bubbles as possible. Alas, the formation of these air bubbles is almost inevitable, while they cannot be tolerated; where the bubble is close to the surface of the part, a hole is formed in the product. There are several ways to combat bubbles using vacuum and high pressure, but we will use a simpler method. The resin, already mixed in the tank, should be heated, for which an ordinary hair dryer is suitable. After heating the resin, it should be left for a couple of minutes, during which time most of the bubbles will come out. Please take a look at the following photos. On the first resin, immediately after heating, bubbles rapidly rise to the surface. In the second photo most of the bubbles have come out.
Step 26. Of course, this method is only applicable to resins with a long polymerization time. The fast-setting epoxy resin that experienced manufacturers work with will most likely harden before we have time to complete all these manipulations, especially since heat accelerates polymerization. Now apply the resin to both halves of the silicone mold. For this I usually use a toothpick or a match. The resin is laid out on the silicone surface in a thin layer, and again you need to try not to introduce bubbles or create voids.
Step 27: Epoxy resin is applied to each half of the mold with a slight excess of crust. At this stage, you can heat the resin again, already in the mold, forcing most of the remaining bubbles to come out and making it thinner, which will reduce the thickness of the future flash.
Step 28. Put the halves of the form together. In this case, the excess resin will simply be squeezed out. Sometimes it is recommended to provide channels or cavities in the mold to drain excess resin, but I did not notice much benefit from them and eventually stopped doing them.
Action 29. Press the mold halves tightly together, for example, clamp them between two hard plates fastened with rubber rings, or place them under a load. This is important, since if the mold halves do not fit tightly, the flash will be thicker, not to mention the fact that the resin may simply leak out. On the other hand, you shouldn’t be too zealous either, since the mold is elastic, and strong compression can deform it and the future casting.
Step 30. When choosing the position in which we will leave the mold with liquid resin inside, it makes sense to take into account the following consideration. Despite our efforts to control air bubbles, one or two of the most stubborn air bubbles are likely to remain in the resin. What will happen to them next? They will most likely rise to the top and remain on the surface, creating tiny holes in the finished casting. But where the casting will have the upper hand is up to us. It makes sense to position the form so that the part on top is where the bubbles will be less noticeable, or where it will be easier to seal them.
Now all that remains is to wait. The readiness of the casting can be judged by the resin squeezed out. Take your time! If the resin has not yet fully cured, the casting may be damaged when removed from the mold. In my case, I do not touch the mold with resin for 24 hours. After this time, the halves of the mold can be carefully separated and removed
Step 31. Dried stains are carefully removed with a match or toothpick, after which the remaining minor seam can be treated with fine sandpaper.
Act 33. That's all. Our epoxy resin casting, absolutely identical to the original, is ready.
As you can see, everything is quite simple and modern, having gained experience on such small products, you will be able to produce serious products that are in demand on the market, and you will also be able to independently make silicone molds to expand your activities and expand the range, and most importantly, you will be able to make molds from silicone and not depend on that range which is offered today.
Here is an example of pouring silicone into open matrices
An example of a silicone mold and a finished product made from silicone molds. Silicone molds
Removing the silicone mold from the finished product. How to remove a silicone mold from a finished product
You can ask and discuss all questions on our forum.
Almost everyone is familiar with such a material as silicone. Men use sealants made from this material. Women often use molds made from it for baking. Many different items are made from it. I wonder if it is possible to make soft silicone on your own at home, as well as forms from it? Yes, you can! Read below to learn how to do it yourself. Production will not take much time, and the simple composition will make it easy to make at home.
What is needed to make silicone
The following materials are required:
Before you start making a rubber-like material, you need to ensure safe conditions. The work must be carried out with rubber gloves, because this material itself is very toxic.
It is also necessary to choose the right place to carry out the work. The room should be good ventilate. The ideal conditions for working on creating silicone products are outdoors. But if this is not possible, then you can do the work on the balcony.
It is also worth knowing the peculiarity of the material - fast hardening. Therefore, it is recommended to produce molding material in small quantities or to carry out all actions quickly.
Other materials can be used to make silicone:
Place sealant in a plastic cup. Add glycerin and paint to it. To do this, it is convenient to use a pipette or straw. Add white spirit. Now you need to mix the mixture thoroughly so that the mass is homogeneous. Silicone is ready! It will remain in a liquid state for about 4–5 hours, and then the pouring silicone will harden, and then it will be difficult to melt it.
First of all, to make the material you need to mix ethyl alcohol with liquid glass in equal proportions. This can be done in any plastic container. During mixing, you need to add dye to the mass according to your own preferences.
Both a wooden stick and a regular spoon are suitable for kneading. After kneading, you will get a mass reminiscent of casting, plasticine or rubber. It can be used in several ways in the future. For example, knead with your hands. You can also put the mixture into a regular cooking bag, a gun for construction silicone or a syringe with the necessary attachments and squeeze out the amount that is needed. You can use regular cookie cutters or take some. Or another option is to cast the required shape.
Important! Repeating the shape of an object will only be possible if you apply silicone mass to the outside of the object. To put it another way, apply the mass not into the mold, but from the outside.
Another important point: before applying the rubber mass, the surface should be lubricated with vegetable oil or soapy water.
How to make a silicone mold
For this you will need special material - compound, which consists of:
- catalyst (hardening agent)
- silicone pastes.
Thanks to these components, any shape can be cast. True, this is not exactly injection-molded silicone (it is more reminiscent of rubber in its properties), nevertheless.
To make an analogue in the form of a silicone mold, you need to do a number of steps:
The required silicone mold is ready!
How to make a mold on a plate
To do this you will need liquid/cast silicone.
The stages of work are as follows:
- A plaster or foam plate must be treated with soapy water.
- Take a brush and apply silicone to the surface.
- Now we need to work out the details. Particular attention must be paid to the top layer.
- Wait until the silicone dries.
Now all that remains is to remove the silicone and the required shape on the plate is ready!
How to make a mold from silicone sealant
There are no difficulties here either. You will need any silicone sealant.
Stages of work:
You can also do this. Roll the silicone dough into a ball and press the dough into it. Align the edges. After a few hours, check whether the silicone has hardened or not. If yes, then the workpiece can be removed. The resulting homemade form is ready!
Work very interesting with the material, especially creative people. You can do whatever you want with this material, make various castings for makeup, make an unusual toy or figurine, make a silicone mask, and also use it as glue for crafts. The technology for making complex products, of course, requires certain skills, but simple figures are not difficult to make even for a child. However, if you want to use such a silicone mold for baking, then you should refuse such a desire; it is not suitable for food use. It is better to purchase an industrial silicone mold.
On the Internet you can find many videos that detail how to make silicone and molds with your own hands, as well as how you can replace some components.
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 molds. 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.
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