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Three Ways to Apply and Cure Mold Release for Rotational Molding

Jul 11, 2018, 18:10 PM

By: The Stoner Molding Solutions Experts

Proper application and curing of mold release in the plastic industry will mean maximizing the value those products add to your process. Every molder wants to get as many releases out of every application with less down time and less waste. Let’s dive in to see how we recommend you cure your semi-permanent plastic mold releases when Rotationally Molding.

Recommended Procedure

  1. Clean mold thoroughly - using glass or plastic bead media, abrasive pads and cleaning solvent or high pH detergent like Stoners A538 All Purpose Cleaner - to remove all prior mold release and other sources of contamination.
  2. If spraying, use spray equipment that provides a fine mist. When wiping, lightly dampen a clean cotton cloth with TraSys® 420 after agitation.
  3. After agitation, apply lightly to the mold’s surfaces, making certain that all areas of the mold are evenly coated.
  4. A minimum inner mold temperature of 132°C (270°F) is recommended to cure the release. This can easily be accomplished after application by running the empty mold through a Production cycle with the oven temperature at 170°C (350°F), normally 5 to 10 minutes. Proper curing will give a bond between mold and coating that will ensure no transfer of coating to the first molded part, as well as ensure the most effective coating for durability and cycle life.
  5. When spot touch-ups are applied, curing the freshly coated area with a heat gun will further enhance the bond between the coating and the mold’s surface. Larger applications may require a bake cycle as described above.

Alternatives to this process - in step 4 above - -  you can apply the mold release to a tool that is still warm after production, close, and let it sit when the plant is shut down over the weekend.


You can apply the Mold Release to the tool that is still warm, close, and store the tool. When the tool is put back into service the tool is already coated and the Mold Release is cured and ready to mold parts.

In each of these three cases it is recommended that sufficient time and temperature be allowed; thereby, insuring that the mold release has sufficient time/temperature to fully cure. Without the cure time the mold Release will not perform optimally, resin can cure into the mold release thereby negatively impact the mold release performance, the part surface, and length of time between re-coating the tool is reduced.

If you have questions about any of these steps and how you can apply them to your process, please reach out to us. The Stoner Molding Solutions experts are eager to assist you in saving time and money with proper mold release application and curing.

Stoner Molding Solutions is a leading supplier of industrial mold release agents in the polyurethane, plastic, rubber and composites fields, based in Quarryville, Pa. For more information, call +1-717-786-7355 or visit www.stonermolding.com

P r o c e s s i n g . . .