How to Choose the Right Epoxy
Updated July 25, 2024
When considering which type of epoxy to choose, there are many factors to consider. Along with taking into account the substrate materials and the specific application, you will also want to think about the working time of the epoxy.
What Is Epoxy Work Time?
An epoxy’s working time, or sometimes called working life, is the amount of time you have to manipulate the adhesive before it starts to harden and dry or cure. In more scientific terms, it is the amount of time the epoxy’s viscosity is low enough that it can still be applied to a substrate.
An epoxy’s work time can vary from application to application. If you wait too long and miss the window of the epoxy’s working life, the bond will not be as strong and may eventually lead to bond failure.
Similar to work time, and sometimes confused with it, is pot life. An epoxy’s pot life is the amount of time that it takes the initial viscosity to double or the amount of time the product is still usable after being mixed.
Both the epoxy work life and the pot life can change slightly. Some factors that can impact epoxy working time include:
- Temperature
- The substrates being bonded
- Exposure to UV light
- Humidity
- Application method
Type of Work Life for Epoxy
Different epoxy adhesives have different working times. In general, these times are broken down into three groups: short, medium, and long. To ensure you select the right epoxy for your application, you need to understand these different working times of epoxy.
Short Work Life Epoxies 
Short working time epoxies will generally take anywhere from three to ten minutes to set. While these products have fast set times, they may still take up to 24 hours to fully cure. You just only have three to ten minutes after mixing to adjust the parts or make changes to the epoxied area. These products can be beneficial for faster production turnaround times.
The Infinity Bond EP 100 clear epoxy is a two-part adhesive that bonds well to a variety of different substrates like glass, ceramics, plastics, and metals. With a short working time, it cures in three to five minutes. It is great for quick repairs or bonding small parts together.
Medium Work Life Epoxies
A medium working time epoxy will generally have a working time between 20 and 40 minutes. This longer work life is ideal for a lot of commercial projects because you have more time to adjust parts as needed after application. Especially if the application’s purpose is to reinforce joints or weight-bearing anchors, the extra work time can be beneficial. A medium work time epoxy may also be useful for water or airtight applications.
A medium work life epoxy, Infinity Bond white EP 420 has a working life of twenty to thirty minutes. It can be used to bond different materials like metals, ceramics, and plastic. It also has a shear strength of 4,000 to 5,00 psi and can withstand harsh environmental conditions including exposure to water, salt, and acid.
Long Work Life Epoxies
A long working time epoxy is typically used for heavy duty or very precise applications. The working time may be 60 minutes, 100 minutes, or longer depending on the specific product. This extended working time gives a lot of flexibility during manufacturing to adjust parts and ensure the alignment is correct. These long work time epoxies can be especially useful in engineering systems or when multiple parts are working in tandem.
If you are looking for an epoxy with an extended work life, the Infinity Bond EP 190 epoxy adhesive may be a good choice for you. It has a work life of seventy to one hundred minutes and can bond with metal, glass, and plastic.
The right epoxy resin working time will give you enough time to complete the job but will not be so long that the extra time could delay your project getting finished.
How to Increase Epoxy Work Time
In some cases, you may want to try to increase your epoxy working time. To do this, you need to slow down the reaction and reduce the rate of exotherm. While picking a long work life epoxy is one option, there are other ways to manipulate an epoxy’s working time.
- Decrease the temperature. For some products, a lower temperature will slow down how fast it cures and increase the epoxy’s work time. You may want to put the mixing pot in cool water.
- Remove UV light. Exposure to UV light such as sunlight can in some cases accelerate the UV process and decrease an epoxy’s work time.
- Spread out the epoxy. When close together, the epoxy will heat up and cure faster. Pour the epoxy into a larger container with a wider diameter to spread it out more.
- Decrease humidity. Humidity may speed up the working and cure time. In some cases, it may even cause other issues with the bond.
While manipulating these factors may help you slow down (or conversely, speed up) the epoxy working time, you do not want to rely on them to drastically change the timeline. Instead, an epoxy with a more appropriate working time may be a better option.
Learn More
Strength and durability are important factors when selecting a product but so is the working time. If you have questions about epoxy working times for your project or about epoxies in general, contact us. Our knowledgeable staff is happy to assist.
