Had that epoxy resin sitting in the basement for a while? Maybe someone offered you their old stuff? Don’t worry – we’ll cover all about epoxy shelf life here.
Does epoxy resin ever expire? Yes, of course all epoxy resin and hardeners have shelf lives. However, the shelf-life of these products tends to be long, usually a year or more depending on what it is. The hardeners for epoxy resins are the more concerning (though still long-lived) materials. It is suggested that most hardeners are used within a year closed, or 6 months if opened.
Although the 6 month – 1 year shelf life is a good general rule, you may be able to get away with more (or less) than that.
Can You Use Expired Epoxy?
Although most epoxies (if not all) will have a shelf life, this is not a true indicator of effectiveness. Often the shelf life is imposed by regulations, or it is a general warning that predicts discoloration or change in pre-mixed textures. You can still use most epoxies well past the predicted lifespan.
How to Know if Epoxy Products are Expired?
First off, they will have an expiration date. Epoxies like ArtResin adhere to the more strict guidelines, 6 months if opened and a year if not. Once you start getting into the higher-grade epoxies, such as West System you will have an indefinite shelf-life.
The biggest indicator, and turnoff, of using old epoxy is going to be the color change. After a while, it will become a yellowish color even after fully cured. Be aware of this before using old epoxy, you wouldn’t want to ruin a project by having a yellow tint in what should be an otherwise crystal-clear pour.
Before using any old epoxy or hardener, make sure to test it out. Get somewhere that the temperature is exactly as required by the brand, and mix a small amount of the epoxy and hardener to completion. If it cures normal, you are able to safely use this epoxy in projects.
Why Would Epoxy be Bad but not Expired?
Often times, epoxy may be showing signs of expiration before the dated expiration. This can be crystallization, yellowing color, funny odors, thickening of consistency, or many other things.
These issues are not due to age as much as contamination. Contamination could be caused by substances getting into the container when it was opened (especially if opened in a dusty or wet basement). They could also be caused by sunlight, or temperature at which the epoxy was stored.
Make sure to follow all manufacturer recommended storage protocols, as this is a common issue and a large expense to have to deal with.
What Epoxies are Least Likely to Go Bad?
Although it’s impossible to say for sure, I do have a list of my personal favorite epoxies for all types of DIY projects. Make sure to check it out before starting a project so you don’t make some of the many, many mistakes I made when starting.