Can You Use an EPO-TEK® Product After Its Shelf Life Has Expired?

One of the most common questions we get from customers is: “Can I still use this epoxy after the shelf life has expired?”

While the answer isn’t black and white, there are ways to assess whether an expired EPO-TEK® product may still serve a purpose—especially in non-critical applications like R&D, prototyping, or internal testing.

In this blog, we’ll walk you through:

• What “shelf life” means for epoxy materials
• What to expect after expiration
• How to test your product for continued viability
• When it may be appropriate to use expired material
• And when to avoid it altogether

What Does “Shelf Life” Really Mean?

Shelf life is the guaranteed window of time during which a product is expected to perform as originally specified. For most EPO-TEK® materials, this is one year at room temperature, unless otherwise stated on the product’s technical datasheet.

That said, some formulations—especially single-component or UV-cure systems—may have shorter shelf lives (as little as six months) due to their unique chemistry. Always refer to the individual product datasheet for the exact shelf-life duration.

Does EPO-TEK® Guarantee Performance After Expiration?

No. Epoxy Technology, Inc. does not guarantee the performance of any product used after its expiration date.

• We do not re-certify expired material
• We do not provide written confirmation of an expired material’s continued viability
• We cannot guarantee results if used past shelf life

However, we understand that certain scenarios—such as internal testing or rapid prototyping—may still call for evaluation of expired materials. The good news? There are simple, low-risk methods to assess whether the material still performs.

How to Evaluate Expired EPO-TEK® Materials

If you choose to test an expired product, follow these best practices:

1. For Unfilled Epoxies

• Stir Part A and Part B separately before weighing and mixing.
• Apply a small drop of the mixed epoxy onto a glass slide.
• Cure it using the recommended cure schedule from the datasheet.
• Inspect for cure quality: tack-free surface, proper hardness, no cloudiness or separation.

2. For Filled Epoxies

• Again, stir Part A and Part B thoroughly before combining.
• If the product is electrically conductive, set up a conductivity test (contact us if you need guidance).
• If it’s thermally conductive, test as you would for an unfilled system.

👉 Tip: These tests aren’t meant to re-certify the product but can provide a quick way to check whether the resin may still be usable for less critical applications.

When Can You Use Expired Epoxy?

If your testing suggests that the material still cures and performs as expected, it may be suitable for:

• Research & Development
• Internal reliability or process testing
• Sample preparation
• Rapid prototyping

However, we do not guarantee using expired materials in production-level manufacturing or in mission-critical applications.

Important Reminders About Shelf Life

• Shelf life is not extended by refrigeration or freezing, unless specifically stated on the datasheet. In fact, cold storage below recommended temperatures can negatively impact performance.
• Most of our two-component systems with “RT/1 Year” shelf life were not tested to failure, so there’s no official “expiration behavior” to predict past the listed timeframe.

Final Thought

Using epoxy past its shelf life is always a calculated decision. While it’s not guaranteed to work, expired product may still provide value in non-critical settings—if properly evaluated first. With a few simple tests, you can often determine whether it still performs adequately for your intended purpose.

Disclaimer: All information provided is for guidance only and does not guarantee performance. Please refer to the individual product datasheets and safety data sheets (SDS) for specific material details.