Can you store unused resin?

Resin is a versatile material used for many crafting and modeling applications. However, when working with resin, you often mix up more than you need for a project. This leads to the question – can you store unused resin for later use? The short answer is yes, resin can be stored for future projects with proper care.

Quick Tips for Storing Resin

Here are some quick tips for properly storing unused resin:

  • Store resin in an airtight, opaque container to prevent exposure to light and oxygen.
  • Only store resin that has not been mixed with a hardener. Uncured resin has a longer shelf life.
  • Keep resin containers tightly sealed and store them at room temperature away from heat and cold.
  • Write the date opened on the resin container so you know how old it is.
  • Always check older resin for lumps, separation, or strange odors before using.

How Long Can Unused Resin be Stored?

The shelf life of unused resin depends on the specific type of resin:

  • Epoxy resin – Unopened epoxy resin typically lasts 6-12 months from the manufacturing date. Once opened, it’s best used within 6 months.
  • Polyester resin – Unopened polyester resin can last 12-18 months. Opened polyester resin should be used within 3-6 months.
  • UV resin – Unopened UV resin can be stored 6-12 months. Opened UV resin is only good for 2-3 months.

These time frames assume resin is stored properly in an opaque, airtight container at room temperature. Heat, cold, moisture, or light exposure will decrease the shelf life.

Signs Your Resin Has Expired

Here are some signs that your resin may have expired and is no longer usable:

  • The resin has become extremely thick, gelled, or solid.
  • There is a layer of oil on the surface of the resin.
  • Strange odors emanate from the resin when opened.
  • You can see layers or separation in the resin.
  • The resin fails to properly cure when used.
  • The finished resin cast has tacky or soft spots.
  • You experience skin irritation when using the resin.

If you notice any of these signs, it is best to properly dispose of the resin and purchase a fresh supply.

Can You Rejuvenate Old Resin?

There are no approved, reliable methods to rejuvenate resin that has expired or gone bad. While you may come across home remedies like heating or adding solvents to resin, this is not recommended.

Heating or thinning old resin does not reverse chemical changes and can be extremely dangerous. Your best option is to dispose of expired resin safely and avoid health or fire hazards.

Proper Disposal of Resin

Unused resin that has expired should be disposed of properly. Here are some tips for safe resin disposal:

  • Allow resin to fully cure first before disposing. Never pour liquid resin down a drain.
  • Mix in an absorbent material like clay cat litter to solidify liquid resin before throwing away.
  • Dispose of resin in your regular household trash once fully cured and solid.
  • Contact your local waste management company if you have large resin quantities to dispose of.
  • Some communities have hazardous waste collection days to properly dispose of resin.

Be sure to check local guidelines and regulations on resin and chemical disposal. Always handle resin safely by wearing gloves and a mask.

Tips for Storing Resin Long Term

For best results when storing resin long term:

  • Purchase resin in smaller quantities instead of bulk volumes.
  • Select brands that have longer shelf lives, like 6-12 months for epoxy resin.
  • Note manufacturing dates and plan projects within the recommended usage period.
  • Always keep resin containers sealed air tight when not in use.
  • Store containers in a cool, dry place away from direct light and extreme temperatures.
  • Avoid temperature fluctuations – don’t move resin between cold garages and warm studios.
  • Minimize oxygen exposure by keeping containers full with minimal air space.

Frequently Asked Questions

Can you freeze resin to extend the shelf life?

Freezing is not recommended for storing resin long term. The freezing and thawing process can cause moisture contamination and chemical changes in resins that reduce shelf life.

What happens if you use expired resin?

Expired resin may not cure properly. Casts made with old resin may remain tacky or soft, have uncured areas, shrink over time, or have other flaws. Using old resin is not worth the risk of having to redo projects.

Can expired resin make you sick?

Expired resins can develop irritants not present in fresh resin, increasing skin irritation risk. Cured resin made with expired material may also leach chemicals. When disposing of or working with old resin, take precautions like wearing gloves and a mask.

Should resin be refrigerated?

Refrigeration can cause moisture condensation issues so room temperature storage is best. If refrigerated, fully seal containers and allow them to reach room temperature before opening to avoid condensation.

How do you restore old resin?

There are no approved methods for restoring expired resin. Attempted fixes like straining, heating, or adding solvents are dangerous and not effective. Dispose of old resin properly and buy new material.

Storing Different Types of Resin

Epoxy Resin Storage

Epoxy resin has a relatively short shelf life compared to other resins. Follow these epoxy storage tips:

  • Store epoxy resin at room temperature between 60-80°F.
  • Keep containers out of UV light in a dark storage bin or cabinet.
  • Discard epoxy within 6 months of opening.
  • Do not return used epoxy back into the original container.
  • Write opening dates on containers with permanent marker.

Polyester Resin Storage

Polyester resin can last longer unopened compared to other resins. Follow these storage guidelines:

  • Keep polyester resin containers tightly sealed when stored.
  • Store in a cool area around room temperature.
  • Discard opened polyester resin after 3-6 months.
  • Do not store containers directly on concrete, which can cause temperature fluctuations.
  • Stir polyester resin before each use to check for separation.

UV Resin Storage

UV resin has the shortest shelf life once opened. Follow these tips for storing UV resin:

  • Keep UV resin out of all light exposure when stored.
  • Discard opened UV resin bottles after 2-3 months.
  • Do not return used resin back into original packaging.
  • Store several smaller bottles instead of one large container.
  • Never freeze or refrigerate UV resin.

How to Organize Resin Storage

Proper storage organization helps protect your resin investment and keeps different resins separate. Some tips include:

  • Label each container clearly with the type of resin inside and opening date.
  • Place resins in sealed plastic bins or bags to contain any leaks.
  • Store flammable resins away from ignition sources in a dedicated space.
  • Keep resin workspaces and storage areas well-ventilated.
  • Shelve resin in storage racks, cabinets, or stackable crates.
  • Use shelves lined with cardboard or acrylic to prevent direct concrete contact.
  • Store resin at eye level for easy inspection and access.

Alternative Uses for Old Resin

Instead of disposing of expired resin, some artists have found ways to use up small amounts of old resin when mixed with fresh material. Some options include:

  • Using old resin for seal coats on porous surfaces.
  • Mixing a 30% ratio of old resin into new batches for non-critical uses.
  • Trying art techniques like crushed resin or resin paper with spoiled resin.
  • Letting children safely practice mixing and pouring with expired resin.
  • Creating basic castings that don’t require perfect clarity or cure.

However, use extreme caution when mixing old and new resin. Never use old resin for critical applications or high risk projects.


Resin can be stored for future use if containers are properly sealed and kept away from heat, cold, light, and oxygen exposure. Epoxy resin lasts about 6 months after opening while polyester and UV resin have slightly longer shelf lives. There is no approved way to restore spoiled resin – disposal and buying fresh supplies is best practice. With proper storage and handling, resin can be kept for a reasonable time without going bad.

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