crystallized resin

[DanaDCole]

The two, four-gallon containers of MAS resin arrived last November. I put one in the garage, where it sometimes got down close to forty degrees when I was not doing any epoxy work. The other container was kept in the laundry room adjacent to the garage where the temp is always around 68 degrees. A few days ago I noticed a milky area about four inches wide in the bottom of the garage-stored container, and upon close inspection found one that was about 1/2 inch wide in the bottom of the container in the laundry room.

I wrote MAS Epoxies about this. Here is what they wrote back:

From what you are describing it sounds like your resin has become crystalized. Crystallization can make epoxy resins appear cloudy, chunky or even solid and is typically an inconvenience rather than a problem as an increase in temperature throughout the container for a few hours will re-melt the resin. DO NOT use material that has any signs of crystallization until it has been re-melted. To re-melt, simply increase the temperature of the material throughout the container to about 140°F until the crystals dissolve and the material turns back into a clear liquid. Before allowing the material to cool down, ensure that all potential crystals have melted and can no longer act as "seed crystals." This can be done by stirring the material or shaking the container after the product has re-melted. Also make sure that the caps, pipes and pumps are free of crystallized material before continuing use with the epoxy. The following methods of heating a container full of resin have worked well for customers in the past:
1. Fill a large basin full of very hot tap water, and set the sealed container of material in it until the resin has re-melted. Refresh the basin with hot water as needed.
2. Cover the container of material in black plastic and place in direct sun light on a hot day.
3. Place the container of material near an incandescent shop light. Be careful not to have the container too close to the bulb or the container will melt.
Never heat up an epoxy resin or hardener in a container or appliance that may come in contact with food or be used in food preparation. After use, tightly reseal all containers and store products on a raised surface off the floor during cold weather and avoid storing near outside walls or doors. Do not allow epoxy resins or hardeners to freeze during winter storage. Instead, try to store between 60-90°F in a dry place. Let me know if you have any questions or need anything else.

Regards,

Michael Schroeder
Product Development
Endurance Technologies, Inc.
(800) 755-8568

[DanaDCole]

Today I placed the two containers of resin in a large plastic vat and filled it with very hot water. Left it sitting in the sun for a few hours. The resin looks fine now.

[Prelude]

I have the same issue from time to time. Warm it up in a warm water bath and it's as good as new. I've never had an issue with use after this event.