How to store resin

How to store resin

Making sure your resin is stored properly will ensure a long happy life for your resin.  Here are a few suggestions on how keep your resin in its best shape for as long as possible.

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.

Like this post? You may be interested in  MasterCast resin TotalCast resin FAQ



Thank you so much as I never did check if my Resin had an expiration date.. but will in the future.


I used some outdated resin to make a base for a votive candle. It turned dark amer when it cured. It looked very nice with the lit candle, so I didn’t mind, but it isn’t the effect I’d want with most of my jewelry.

Alice Ryan

I label the lids with marker, either R or H to help me be sure I’m not mixing them up.


Until recently it was necessary to heat resin prior to mixing it. That is no longer necessary (going by my last two purchases of resin). But the unheated resin is much less rigid than the old, heated kind.
For my pieces, I don’t want it to cure so comparably softly. Any ideas to make it cure harder?


Hi, I have recently started to use resin. I’m pouring it into a glass vase. I can’t seem to get rid of the bubbles. Unfortunately a huge bubble developed. Almost like an ice cube. It wasn’t there while it was in liquid form but as it started to set it appeared. I was just wondering why that might have happened and how to prevent that in future.

Katherine Swift

Hi Jo, I’m sorry to hear you had a problem with bubbles. Bubbles sometimes form later because as resin cures, it heats up, causing bubbles. You can avoid this on future castings by doing your pours in smaller batches. Allow one layer to partially cure before pouring the next layer.


Hi there, great site. I am using a 2 part filled casting epoxy. I’ve had three batches harden in the can. The only factor I can think of is that they are stored with a plastic pouring lid. The lid is sealed, but the can is metal, so is it possible the plastic lid is somehow reacting with the resin to set it off?

Katherine Swift

I don’t think a plastic lid is the problem. What kind of resin — epoxy, polyurethane, polyester or something else?


Can I transfer my resin from the plastic bottle I got it in, to an empty & clean glass nail polish bottle?
..coz my plastic bottle lid & nozzle, keeps clogging.

Katherine Swift

Unmixed resin? The answer is yes — but I don’t know if there will be a reaction with the resin and unused nail polish that will cause it from curing later. It sounds like you are cleaning them. Make sure to do it well and you should be okay.

sue clementz

I use the half bubble mold(428) put a flower inside of it and fill with resin. I dry my flower first, do u need to do anything else to the flower before putting in resin?


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