Epoxy Work Life - Choosing the Perfect Cure Time
When considering which type of epoxy to choose, several obvious questions come to mind. Your first question is probably, “what substrates does it bond best?” Your next question likely tackles what environmental conditions your epoxy can withstand. But before you commit to an epoxy, don’t forget to consider the work life.
Not to be confused with pot life (which reveals how long an activated epoxy will last in your working tub before beginning to harden), work life relates to cure time. Working life refers to how long your epoxy needs before it is hardened and dry. Although you can accelerate this process with certain epoxies by applying UV light or heat to the cured surface, choosing the right work life can save you aggravation and possible damage to your substrates.
This is where the Goldilocks system comes in. Depending on your application, you need to choose an epoxy with a work life that isn’t too short to complete your job and isn’t too long that your finished product is delayed. In other words: not too short, not too long, but just right. Understanding common applications for short, medium, and long epoxy cure times will help you determine the work life that is best for your project.
SHORT WORK LIFE EPOXIES:
When referring to an epoxy adhesive with a short work life, you can expect to wait no more than three to ten minutes for the epoxy to set. Although some short work life epoxies may not be fully cured for up to 24 hours, after that ten minute mark, you will not be able to adjust your parts or make changes to the epoxied area. Short work life epoxies such as the ASI 5-Minute Epoxy (in black or clear) are ideal for quick repairs. They bond well with a variety of surfaces such as ceramics and plastics, so you can reinforce cracks, mend broken household parts, or repair leather and fabric fasteners. Thanks to the shorter work life, these epoxies can be helpful if you have a vertical application and need to hold your item in place with precision. Your arms get tired. Short work life epoxy doesn’t.
MEDIUM WORK LIFE EPOXIES:
Many commercial projects call for epoxy with a medium work life. Because these epoxies begin to cure in 20 to 40 minutes, you have time to adjust your parts. This is especially important if you are using epoxy to reinforce joints and weight-bearing anchors, or need time to ensure your work is precise for water or airtight applications. The ASI 20-Minute Epoxy is a two-part, general-purpose epoxy that fits the bill and is most commonly used to bond metals, ceramics, or plastics. Medium work life epoxies usually pack an extra punch and can withstand harsher external and environmental conditions, such as water, salt and acid exposure. The ASI 20-Minute Epoxy even boasts shear strength of 2,000-4,000 psi.
LONG WORK LIFE EPOXIES:
Long work life epoxies – the “papa bears” of the adhesive world – are critical for heavy-duty applications where precision is key. The longer open time gives you the most flexibility to adjust parts for precision and alignment. If your parts fit into an engineering system, or work alongside other parts, the longer work life of epoxies such as the ASI Long Worklife Epoxy makes your job much easier. With up to 100 minutes of work life, these epoxies make metal and plastic bonding a breeze. Like many other epoxies, you can accelerate the cure by applying heat, so you can finish your project when you’re ready – not when your epoxy is.
Although other properties of your epoxy, such as viscosity or weight bearing capabilities, may jump out first during your selection process, considering your epoxy work life is a necessary component to consider so you choose the most efficient materials for the job.
Questions on finding the perfect epoxy or adhesive work life for your application? Contact us to speak with an adhesive engineer today.