How to Mix Polyester Resin

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Things You'll Need

  • Polyester resin

  • Methyl ethyl ketone peroxide (MEKP)

  • Wooden stirrer

  • Mixing container

Polyester resin

Polyester resin is most commonly used in the manufacturing of boats, surfboards, kayaks and other nautical vessels. Because of its easy application and durability, polyester resin is also applied to patch cracks and holes that need to remain watertight. Polyester resin comes in a wide range of colors and finishes to customize any project. These resins are available at many home improvement stores and online retailers. The following steps will explain how to mix polyester resin.


Step 1

Mixing supplies

Set up the polyester resin mixing supplies in a well-ventilated area. An open garage or an outdoor work area is advised. Do not mix the resin near a heat source or under direct heat. Doing so will cause a chemical reaction.

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Step 2

Mixing resin

Mix the polyester resin with a catalyst named methyl ethyl ketone peroxide (MEKP) to begin curing. Depending on the amount of resin needed, pour the appropriate ratios of polyester resin and MEKP into a heavy-duty plastic tub or bucket. The standard ratio is 1 oz. of MEKP to 1 gallon of polyester resin. For smaller quantities, please refer to the ratios below. 1 oz resin: 20 drops MEKP 16 oz resin: 1/8 oz MEKP 32 oz resin: 1/4 oz MEKP 64 oz resin: 1/2 oz MEKP


Step 3

Use a long wooden stirrer to gently stir together the polyester resin and the MEKP. Resin often floats to the top, so it is sometimes necessary to stir from the bottom of the container to fully mix the products. Continue to slowly stir the mixture until it reaches the consistency of toothpaste.


Step 4

Color mix

Add the appropriate amount of color mix to the polyester resin if a color is desired. A wax powder may also be added to give a polished look to the resin once it is applied. Follow the manufacturer's instructions to determine the correct quantities of color or wax to be mixed.


Step 5

The resin mix will be usable for approximately 15 to 20 minutes before it will begin to harden. Apply the polyester resin to your project before this time elapses.


Some polyester resin manufacturers will include a color and wax mix with the resin purchase.


Wear heavy-duty gloves, safety glasses and a respiration mask when mixing polyester resin. Polyester resin is highly flammable. Keep away from heat.


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