It's a common scenario: You've gotten the epoxy you need for your project but aren't yet ready to start, or maybe you have a significant amount of unmixed epoxy left over from a finished project. When such things occur, it becomes necessary to store the remaining epoxy components safely for future use.
Typically, this isn't much of an issue, but there are a few factors that affect the quality of the epoxy over time, even when still in its original container.
We'll cover those issues here in the segments below:
Proper storage of unopened epoxy resin
Once our UltraClear Table Top Epoxy is delivered to your home, it's a good idea to bring it into a warm controlled space to preserve its life span. Unmixed epoxy components fare particularly well within a consistent temperature range of 60°F to 80°F.
It's also good to keep it in a dry place, where it will be safe from humidity once opened.
What is the shelf life of unmixed epoxy?
There isn't much variation in the shelf life of each epoxy component. What affects it most is whether or not the containers have been opened, as well as if containers which have been opened are properly resealed.
For unopened containers, shelf life is straightforward. Assuming the components are stored in a dry, warm place, you'll have:
- For our UltraClear table top epoxy: A shelf life of one year
- For our UltraClear deep pour epoxy: A shelf life of one year
However, if you've already opened the containers, the remaining shelf life is considerably shorter, as oxygen has now been introduced into the bottles. This hastens a process called oxidation, which is part of what causes some epoxy components to take on a yellowish hue over time.
You can reduce the rate of this by making sure you tightly seal the bottle cap back on after pouring what you need. It's a good idea to check the cap and sides of the bottle opening to make sure there isn't residue preventing a good seal.
Regardless, once a bottle is opened, its contents are on a clock.
For bottles of epoxy resin and hardener that have been opened at least once, shelf life becomes roughly the following:
- For our UltraClear table top epoxy components: About two months
- For our UltraClear deep pour epoxy components: About two months
As you can see, these times are the same. It really is mostly environmental factors that affect the "yellowing" of those substances.
This is an industry wide concern, affecting every brand, as it is a fundamental characteristic of epoxy and many other polymers and plastics. For epoxy, it is most noticeable with clear resins, meaning those used primarily for their glasslike appearance.
The best way to avoid it is to only purchase what you need (and usually a little extra to be safe), and use it all for your project once you open the containers. You can always order more for future projects.
What else causes "yellowing" in epoxy? Can it be prevented?
There's one other factor that tends to cause "yellowing" in epoxy: sunlight.
Consistent, direct exposure to sunlight will over time slowly cause the epoxy to change to a more yellowish hue. This will occur even in epoxy that has already fully cured (hardened).
Avoiding it for indoor projects like kitchen countertops or for unused epoxy is pretty obvious. Just limit sunlight exposure from uncovered windows or open doorways/entrances. Blinds, curtains, drapes, can all obstruct the sunlight to varying degrees for windows.
For projects intended to be left outdoors, this is a bit more difficult. One solution is to make sure the epoxy surface is given shade from the sun. For instance, a table with a large umbrella overhead will block much of the day's sunlight from bearing down on the epoxy, especially at the peak intensity hours around noon.
In the case of an outdoor epoxy bar top, constructing an overhang or some other kind of cover to mitigate direct sun exposure is a good way to preserve the aesthetic lifetime of the epoxy.
Note, however, that this concern is most noticeable with clear epoxy over a light colored substrate, as well as opaque epoxy that has been given a white colorant.
If your epoxy has been tinted by any of our pigment additives, you may never notice any yellowing, as pigment colors will shift very little if at all over time and are stronger sources of color compared to the natural yellowing.
So, to recap on how to avoid epoxy yellowing:
- Keep unmixed epoxy stored within a temperature range of 60°F to 80°F
- Keep unmixed epoxy stored in a dry place
- Keep all epoxy away from direct, constant sunlight exposure
Following these guidelines will help give your epoxy in any state its longest possible lifespan.
Have questions? Want planning advice? Contact us!
If you have any questions about the information in this article, or about anything related to epoxy at all, you can contact us for assistance. Our epoxy experts are here to provide answers and can also help you with planning your epoxy project.
It's always good to make sure you'll have the supplies and tools you'll need, as well as the correct volume of epoxy to make sure your project can be completed the way you envision.
Contact us via email or phone here, or you can also text-chat directly online with one of our experts by clicking the help button at the bottom right of your screen.
