How to store resin
1. Store upright in its original containers. Resin is sold in containers that are compatible with it and should not cause any reactions to degrade the product.
2. Do not store mixed resin. Once it’s mixed you have to use it or lose it. Otherwise, you will have a hard block of resin when you go to use it.
3. Store in a cool, dark place. I like to use the bottom of a closet.
4. Do not store in direct sunlight. The UV light can speed up the degradation of your product.
5. Store where the resin will not be subject to temperature swings, like a garage, attic or freezer. 70 degrees F is ideal.
6. Mark somewhere on your resin containers when you purchased the resin. This will help with making sure you use it up in a timely fashion.
7. Store resin bottles in a plastic bag and/or larger plastic container. If something does spill, it will be easier to contain the mess.
8. Familiarize yourself with the shelf life of the products you are using. While most epoxy resins have a shelf life of a year, some resins, such as polyesters and polyurethanes, have a much shorter shelf life. I recommend only purchasing the amount of resin you can comfortably use within half of the shelf life time.
Once your resin is open, here are a few other suggestions I like to follow:
1. Only remove one cap at a time. Sadly, putting the hardener cap on the resin container (or vice versa) is all it takes to permanently close the bottles. I like to pour the contents from one bottle, then replace the cap before opening the next bottle.
2. When I run out of one container, even if I have some left in the other container, I always dispose of it properly. I always start a fresh kit with both products new instead of using an aged product from an old bottle.
3. If the shelf life of a resin has expired, do not fear. You may still be able to use it for your projects (assuming it has been stored properly). For example, many epoxy resins will continue to cure after the shelf life has expired, but may cure with an amber color. If you are coloring the resin, this will unlikely be noticeable.