How to work with epoxy resin?

Epoxy resin, being a versatile polymer material, is used not only for industrial purposes or repair work, but also for creativity. Using resin, you can create beautiful jewelry, souvenirs, dishes, decor items, furniture, and so on. An epoxy product consists of two components, so you need to know how and in what proportions they are applied. In this article, we'll take a closer look at how to work with epoxy.

You can work with epoxy resin at home. In order for such work to be enjoyable, and the result of creative work to please and inspire, it is necessary to know and follow the basic rules for using this polymer.

• When mixing the components, the proportions must be strictly observed. The number of components mixed with each other depends on the grade of epoxy and the manufacturer's recommendations. If you are the first to develop with a brand of polymer resin that is new for yourself, then you should not rely on previous experience here - each type of resin composition has its own characteristics. If you make a mistake, the resulting mixture may not be usable. In addition, the proportions of epoxy and hardener must be strictly observed in terms of weight or volume. For example, to measure the exact amount of ingredients, a medical syringe is used - a separate one for each component. Mix the polymer resin ingredients in a separate bowl, not the one with which you measured.
• The connection of the components must be performed in a certain sequence, if it is violated, then the composition will begin polymerization ahead of time. When mixing, add the hardener to the base, but not vice versa. Pour in slowly, while slowly stirring the composition for 5 minutes. When stirring, air bubbles trapped in the composition when the hardener is poured will leave the resin. If, when combining the ingredients, the mass turned out to be excessively viscous and thick, then it is heated to + 40 ° C in a water bath.
• Epoxy is very sensitive to ambient temperature. When the resin component is mixed with the hardener, a chemical reaction occurs with the release of heat. The larger the volume of the mixture, the more heat energy is released when the components are combined. The temperature of the mixture during this process can reach more than + 500 ° C. Therefore, the mixture of the resin component and the hardener is poured for operation into molds made of heat-resistant material. Usually the resin hardens at room temperature, but if it is necessary to speed up this process, then the original ingredients must be preheated.

The polymer resin mixture can be applied in a thin layer or bulk molded into a prepared mold. Often, epoxy resin is used to impregnate it with a structural glass fabric.

You can make a ready-made epoxy composition with your own hands at home if you properly dilute the resin with a hardener. The mixing ratio is usually 10 parts of resin to 1 part of hardener. This ratio may be different, depending on the type of epoxy composition.For example, there are formulations where it is necessary to mix 5 parts of polymer resin and 1 part of hardener. Before preparing a working polymer composition, it is necessary to calculate the amount of epoxy that is needed to complete a particular task. The calculation of the resin consumption can be made on the assumption that for pouring 1 m² of area per 1 mm layer thickness, 1.1 liters of the finished mixture will be required. Accordingly, if you need to pour a layer equal to 10 mm on the same area, you will have to dilute the resin with a hardener to get 11 liters of the finished composition.

Hardener for epoxy resin - PEPA or TETA, is a chemical catalyst for the polymerization process. The introduction of this component into the composition of the epoxy resin mixture in the required amount provides the finished product with strength and durability, and also affects the transparency of the material.

The resin can be prepared in varying amounts of volume.

• Small volume cooking. The epoxy resin components are cold mixed at room temperature not exceeding + 25 ° C. It is not recommended to mix all the required amount of material at once. To begin with, you can try to make a test batch and see how it will solidify and what features it has. When mixing a small amount of epoxy resin and hardener, heat will be generated, so you need to prepare special dishes for working with the polymer, as well as a place where this container with hot contents can be placed. Mix the polymer components slowly and carefully so that there are no air bubbles in the mixture. The finished resin composition must be homogeneous, viscous and plastic, with an absolute degree of transparency.
• Large volume cooking. The more ingredients are involved in the mixing process by volume, the more heat is released by the polymer resin composition. For this reason, large quantities of epoxy are prepared using the hot method. For this, the resin is heated in a water bath to a temperature of + 50 ° C. As a result, such a measure allows better mixing of the resin with the hardener and extending its working life before hardening by about 1.5–2 hours. If the temperature rises to + 60 ° C during heating, the polymerization process will accelerate. In addition, it is necessary to ensure that no water gets into the epoxy when heated, which will spoil the polymer so that it loses its adhesive properties and becomes cloudy.

If, as a result of work, it is necessary to obtain a strong and plastic material, then before the introduction of the hardener, a DBF or DEG-1 plasticizer is added to the epoxy resin. Its amount to the total volume of the resin ingredient should not exceed 10%. The plasticizer will increase the resistance of the finished product to vibration and mechanical damage. In 5-10 minutes after the introduction of the plasticizer, the hardener is added to the epoxy resin.

To work with epoxy, you will need the following tools:

• a medical syringe without a needle - 2 pcs.;
• glass or plastic container for mixing components;
• glass or wooden stick;
• polyethylene film;
• aerosol corrector to eliminate air bubbles;
• sandpaper or sander;
• goggles, rubber gloves, respirator;
• coloring pigments, accessories, decorative items;
• molds for filling from silicone.

Any master class for beginners, where training in the technique of working with epoxy resin is carried out, contains instructions for the use of this polymer. Whichever method you decide to use for work, first of all, you need to prepare the work surfaces. They must be cleaned of contamination and high-quality degreasing with alcohol or acetone is carried out.

After this preparatory stage, you can proceed to the next steps.

If you need to glue two parts, then a layer of epoxy resin, no more than 1 mm thick, is applied to the working surface. Then both surfaces with the adhesive are aligned with each other with a tangential sliding motion. This will help to securely bond the parts and ensure that air bubbles are removed. For adhesion strength, the part can be fixed for 2 days in a clamp. When it is required to perform injection molding, the following rules are followed:

• pouring the composition into the mold is necessary in the horizontal direction;
• work is performed indoors at room temperature not lower than + 20 ° C;
• so that after hardening the product easily leaves the mold, its edges are treated with vaseline oil;
• if wood is to be poured, then it must be thoroughly dried.

Drying time of polymer resin depends on its freshness, old resin dries for a long time. Other factors affecting the polymerization time are the type of hardener and its amount in the mixture, the area of ​​the working surface and its thickness, and the ambient temperature. Polymerization and curing of epoxy resin goes through the following stages:

• polymer resin in a liquid consistency fills the entire space of the mold or working plane;
• the consistency viscosity resembles honey and it is already difficult to pour resin relief forms with resin;
• high density, which is only suitable for gluing parts;
• the viscosity is such that when a part is separated from the total mass, a plume is drawn, which hardens right before our eyes;
• epoxy is similar to rubber, it can be pulled, twisted and squeezed;
• the composition polymerized and became solid.

After that, it is necessary to withstand the product for 72 hours without use, so that the polymerization stops completely, and the composition of the material becomes stronger and hardened. The drying process can be accelerated by increasing the room temperature to + 30 ° C. It is noteworthy that in cold air, polymerization slows down. Now, special accelerating additives have been developed, when added, the resin hardens faster, but these funds affect the transparency - the products after their use have a yellowish tint.

To protect yourself when working with the chemical components of epoxy, you must adhere to several rules.

• Skin protection. Work with resin and hardener must only be carried out with rubber gloves. When chemicals come into contact with open skin areas, severe irritation occurs as an allergic reaction. If epoxy or its hardener comes into contact with the skin, remove the composition with a swab soaked in alcohol. Next, the skin is washed with soap and water and smeared with petroleum jelly or castor oil.
• Eye protection. When handling resin, chemical components may splash into eyes and cause burns. To prevent such a development of events, it is necessary to wear safety glasses while working.If chemicals get into your eyes, rinse immediately with plenty of running water. If the burning sensation persists, you will need to seek medical attention.
• Respiratory protection. Hot epoxy fumes are harmful to health. In addition, human lungs can be damaged during the grinding of the cured polymer. To prevent this, you must use a respirator. For safe handling of epoxy, good ventilation or a fume hood must be used.

Proven recommendations from experienced epoxy craftsmen will help beginners learn the basics of the craft and prevent them from making the most common mistakes. To create products with a high level of quality and reliability, you may find a few tips helpful.

• When heating a thick epoxy resin in a water bath, it is necessary to ensure that the temperature does not rise above + 40 ° C and the resin does not boil, which will lead to a decrease in its qualities and properties. If it is necessary to tint the polymer composition, then dry pigments are used for this purpose, which, when added to the resin, must be thoroughly and evenly mixed until a uniform colored mass is obtained. When using a water bath, you need to ensure that not a single drop of water gets into the epoxy resin, otherwise the composition will be cloudy and it will not be possible to restore it.
• After the epoxy resin is mixed with the hardener, the resulting mixture must be used within 30-60 minutes. The remains cannot be saved - they will only have to be thrown away, as they will polymerize. In order not to waste expensive material, it is necessary to carefully calculate the consumption of components before starting work.
• To obtain a high degree of adhesiveness, the surface of work objects must be sanded and well degreased. If the work involves layer-by-layer application of resin, then each subsequent layer is not applied to the completely dried previous one. This stickiness will allow the layers to firmly bond together.
• After casting into a mold or onto a plane, it has to dry for 72 hours. To protect the top layer of the material from dust or small particles, it is necessary to cover the product with plastic wrap. You can use a large lid instead of a film.
• Epoxy resin does not tolerate ultraviolet rays of the sun, under which it acquires a yellow tint. To keep your products at their ideal degree of transparency, choose polymer resin formulations that contain special additives in the form of a UV filter.

When working with epoxy, you need to find a perfectly flat, horizontal surface. Otherwise, the product may end up with an uneven flow of polymer mass on one side. Mastery in working with epoxy comes only through regular practice.

For how to get started with epoxy, see the next video.