Storing Resin?

I have a large jug of resin that I need to move from its present home to probably out to an unheated outbuilding. Lately up here it has been downright cold, that dang windchill! Anyway, will storing it in cold weather effect it in anyway or when warmer weather comes will it be fine to use? Just curious!


cold resin
I have heard of instances where cold resin begins to solidify, forming lumps and small hard crystals in the mix.

Manufacturers will tell you there is no problem and to just warm up the resin (hot water bath) to melt the crystals. I would feel chancy using it on anything but a minor project.

I kept a can of resin for one winter in an unheated basement. The following summer I had no confidence in the contents so I ordered a new can of resin.

Your best bet may be to keep it a full as possible, in a nicely warm room, close to the TV to serve as an inspiration.

Ask the manufacturer
Call their tech support number and get their recommendation for storage and find out what the shelf-life is.

resin is not resin
Is it epoxy resin, polyester resin or vinylester resin? It does make a difference.

Doesn’t it say on the side of the jug???
Usually on items of the sort, it states: “storage” or “store un-used product”

Paddle easy,


Shelf life is a factor
In my expreience polyester resin over about 6 months old is suspect even in good storage conditions. Have had several unpleasant results with old stuff. If it is polyester I pitch it if it is more than 6 months old regardless.

polyester and vinylester resins are
almost always provided with a minute amount of “promoter” in them, so that when MEKP is added, they will go off predictably. However, because of the presence of the promoter, these resins will set up by themselves eventually.

I have also heard of crystallization when these resins are in cold environments. Might reverse slowly in a normally warm environment.

Obviously if you were storing epoxy resin, you would also be storing the hardener. My experience with West epoxy is that the resin will keep indefinitely, though it may thicken a little bit. The harderner, once opened, will gradually turn dark red and thicken, but surprisingly, when mixed with the resin, it still sets up properly.

The reason I quit using vinylester for repairs is that epoxy works just as well on my vinylester boats, and the epoxy keeps a long, long time, while the vinylester will have set up when I go to use it.

The polyester resin I have…
…has instructions recommending refridgeration to extend the shelf life. That’s not the same as freezing it…

If it’s System Three epoxy…
If it’s System Three epoxy resin, the manufacturer’s guide states that extended storage below 50 deg. F will result in crystallization. According to the same guide, you can heat up the resin to bring it back to the proper consistency.

But why? It’s easy enough to keep in the house.