Epoxies have been crucial across a wide array of sectors since the 1940s. Extremely durable and delivered in a liquid form, epoxy resin cures to a temperature-resistant, high-clarity solid. The strength and quick drying times make it ideal for use as a protective coating and filler on a variety of products, including electrical components and flooring.
Various epoxy or synthetic resins have different qualities and can be used for numerous different applications as per the manufacturer’s specifications. There is a vast variety of different resins, which range greatly in the time of the curing process, hardness, and insensitivity of the completed surfaces. Further characteristics for the selection of the appropriate epoxy resin can include considerations such as heat resistance and the maximum thickness that can be applied to the material.
Due to its varied applications, it can be difficult to identify which epoxy is correct for your project. In this epoxy resin guide, we’ll examine what epoxy is and which type is suitable for you.
What is Epoxy Resin?
Resin or epoxy resin is a synthetic material that can be applied in many different uses. The epoxy is made by mixing two components that are matched to each other. When the liquid resin is combined with an appropriate hardener, a chemical process is initiated that typically lasts several hours. After combining the components, not only is heat radiated, but the material also changes from liquid to a solid state. In order for the material to cure completely, the mixing ratio of resin to hardener is normally 1 to 1 or even 1 to 2.
Epoxy, also known as polyepoxide, is a polymer that clings to a variety of surfaces such as wood, metal, concrete, glass, and stone. Once set, epoxy is very strong, dimensionally stable, and chemical-resistant. Its advantages include negligible shrinkage, electrical insulation, and cost-effectiveness, with low toxicity and no VOCs.
The Various Types of Epoxy Resin
There are so many different epoxies on the market that it is easy to feel overwhelmed. But, in essence, just a few types have been adapted for specific jobs. The following are two of the most frequent types of resin:
- Epoxy Resin Casting
Because of its low viscosity and extended pouring time, casting epoxy resin is also known as pouring plastic or deep pour resin. The increased viscosity means it is perfect for filling holes and gaps in materials to enhance their strength and stability when mixed with a 2:1 ratio of resin to hardener.
- Epoxy Resin Coating
This coating is used to provide a robust, waterproof, chip-resistant, and rust-proof finish. Coating resin has a faster curing time when mixed in a 1:1 ratio, and once dried, the coatings are exceptionally durable with an easy-to-clean, high-gloss surface.
What Is the Distinction Between Casting and Coating Epoxy Resins?
Epoxy resins for casting and coating are distinct but similar compounds. Ultimately, the choice between the two determines how the finished product will look and perform.
Casting resins, sometimes known as “deep-pour resin” or “pouring plastic,” are used to create clear encasings and suspensions. The material is poured into a mold and then cured to keep its shape. Casting resins are widely utilized in the production of crafts, jewelry, sculptures, and mementos. Casting resin can also be used to make aggregate, molded plastics, and electrical insulation. Engineers use epoxy resin-fortified composites to create automotive and aircraft parts, sports equipment, and hundreds of other goods.
Coating resins, on the other hand, are appropriately named: They are used to coat materials such as metal, concrete, or wood in order to make them stronger, chip-resistant, simpler to clean, water-resistant, and rust-proof. A small layer of coating resin can also be used to bind objects or preserve paper. Coating resins are applied to overmold circuits and transistors in the electrical manufacturing industry to seal components together and protect against corrosion.
Selecting the Right Epoxy Working Life
There are numerous aspects to consider when deciding on the sort of epoxy to use. You may first wonder, Will this work for my substrates? or Can this endure the environmental conditions that I require? These are crucial things to ask, but don’t forget to include in the working life required for your project.
Working life is related to cure time. It is the amount of time you have before the epoxy hardens and dries. Applying a UV light or heat to certain epoxies can speed up the curing process, but choosing an epoxy with an acceptable working life is the best approach to avoid the annoyance and potential damage to your substrates. The terms working life and pot life are sometimes used interchangeably, but pot life is the amount of time an active epoxy will last in your working tub before hardening.
Epoxies have three distinct working life groups: short, medium, and long. Understanding the differences between these groups is the first step in picking the proper epoxy. The Goldilocks technique is a frequent rule of thumb for epoxy working life choices since it’s critical that your working life offers enough time to complete the job but not so much that your finished project is delayed. The ideal epoxy will have a working life that is neither too lengthy nor too short.
Curing and Processing Time
In the case of synthetic resin, the curing time refers to the amount of time it takes for the components to reach a condition of total hardness and insensitivity after they have been mixed. Most of the time, there is a direct relationship between curing time and processing time: If the processing time is short, the resin usually also cures completely in a relatively short amount of time.
The curing period for goods with a relatively short processing time of 20 minutes to one hour is around 24 hours. Products with processing times of up to 12 hours allow for more complex processing and effects, but the resin takes up to a week to cure entirely.
Viscosity of Epoxy Resin
The viscosity of a liquid describes its resistance to flow. The viscosity of epoxy resin formulas impacts whether the material will drip or spread uniformly and whether it should be poured, dipped, or painted onto the material. The amount of epoxy that perforates the substrate and the physical qualities that are formed are also affected by the viscosity.
- Viscosity: Low
Because low-viscosity epoxy resin is thin, it is ideal for deep penetration and filling small cavities. The consistency aids in the prevention of air bubbles, which aids in the bonding of the epoxy to the substrate. Low-viscosity epoxy resin can be used for encapsulating, sealing, and potting.
2. Viscosity: Medium
Medium-viscosity epoxy is a thick substance. It has higher mechanical strength and is less permeable than low-viscosity formulations. Because of its ability to endure somewhat high temperatures, the material is frequently used for filament winding, vacuum bagging, and tooling.
3. Viscosity: High
The most robust choice is high-viscosity epoxy, which has a paste-like consistency. It has excellent adhesion as well as shock and heat resistance. This mixture is used by technicians for applications that require extraordinary durability and strength.
Important Questions to Ask About Epoxy Resin
If you are unsure about the epoxy resin to use, consider the following:
- How thick of an epoxy layer do you need for this project?
- How long do you have to wait for the epoxy to cure?
- Is a mold or frame required to avoid leakage and to retain the epoxy while it cures?
- How tough must this material be to endure the predicted wear?
- Do you wish to suspend anything in the epoxy resin?
- Is it necessary for the epoxy to have any specific properties?
- Will this material be subjected to high temperatures, water, chemicals, UV radiation, or other potentially harmful elements?
Epoxy resin systems can be customized to meet the specific requirements of each project. Manufacturers employ a wide range of co-reactants, such as polyfunctional amines, phenols, and alcohols, each of which produces somewhat different effects. The type of base epoxy and additives used in the recipe can also affect the viscosity and inherent qualities of the resin.
How Do You Remove Epoxy Resin?
If the resin has yet to cure, you can use methylated spirit and a cloth to wipe away the resin. However, once the glue has dried, removing it can be quite difficult due to its adhesive properties.
If only a little amount of resin needs to be removed, scrape or sand it. Acetone is an effective way to remove epoxy glue from wood or concrete, but be mindful of its combustible qualities, and always use it in a well-ventilated area. A heat gun can soften the resin sufficiently for it to be scraped away with a plastic scraper. To remove resin from plastic or glass, you might alternatively use paint thinner.
Is Epoxy Resin Safe?
Although epoxy resin is a safe material to deal with, there are a few safety measures that must be followed throughout its application. You must always wear gloves to ensure your hands don’t come into contact with the resin and hardener liquids. If you get any liquids on your skin, use baby wipes to remove the chemical and thoroughly wash the area. It is recommended that you wear a plastic apron and safety goggles to protect your eyes. If the epoxy comes into contact with your eyes, flush them thoroughly for 15 minutes and seek medical assistance as soon as possible.
Due to the chemical reactions taking place, it is necessary that you apply epoxy in a space that is well ventilated. Open a window, use a ceiling fan, or wear a respirator to help ensure the air is as clean as possible.
Epoxy resin-based adhesives are the most versatile family of adhesives available today! Because they bond effectively with a wide range of substrates and can be easily manipulated to obtain significantly different properties, they have a wide range of applications in industries such as automotive, industrial, and aerospace. The ability of epoxy adhesive to provide a good mix of handling features and ultimate physical attributes is the primary reason for its widespread acceptance in so many markets.