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Start with mixing · 7 steps

Prepare and mix resin

Polyester is catalyzed with MEKP. Use the percentage specified for your resin; this calculator covers 1 to 3% by volume, with 1.5% as a reference.

Graduated resin cup, mixing stick and catalyst container on a workbench.

  1. Step 1. Identify the resin and its catalyst

    Use MEKP, the catalyst compatible with your polyester resin. Check the technical data sheet for the percentage, whether it is measured by weight or volume, and working conditions. MEKP is not the solvent MEK or an epoxy hardener.

    Identify the complete system

    Check the working conditions

    Check the actual product instructions for compatibility, measurement basis, conditions and protection. Containers are schematic, not product recommendations.

  2. Step 2. Prepare a safe work area

    Provide the ventilation and personal protection specified in the SDS. Keep ignition sources away. Use compatible, clean, dry containers and tools; keep products in their labeled original containers until measuring.

    Prepare the work area

    Use the ventilation and personal protection specified in the SDS. Keep ignition sources away.

  3. Step 3. Organize everything before catalyzing

    Prepare the surface, cut and dry-fit the fiber, and keep tools within reach. Check the permitted working conditions. Do not catalyze until you are ready to apply.

    Cut and dry-fit the fiber

    Have the tools ready

    Prepare the surface, reinforcement and tools before catalyzing. The illustrated fiber stack is not a laminate schedule.

  4. Step 4. Measure a manageable amount

    Measure only what you can apply within the manufacturer's working time and batch limits. By volume: 1 US pint = 16 fl oz, 1 US quart = 32 fl oz and 1 US gallon = 128 fl oz. Weight and volume are not interchangeable.

    A scale measures mass in grams or ounces; a graduated cup measures volume in milliliters or fluid ounces.
    Use the units in the product instructions. Weight and volume are not interchangeable.

  5. Step 5. Add the specified catalyst

    Select the MEKP percentage allowed for your resin. By volume, 16 US fl oz of resin at 1.5% requires approximately 7.1 mL of MEKP. Measure the catalyst with a compatible dispenser and add it to the resin; do not estimate by eye.

    Add the measured catalyst

    Mix uniformly

    Use the specified MEKP, amount and measurement basis. Mix and apply within the product working time; do not estimate by drops.

    MEKP calculator

    Enter the resin amount and the percentage specified for your product.

    Resin amount and MEKP percentage

    US fluid ounces, not weight.

    Use 1–3% only if your technical data sheet allows it.

    MEKP required

    7.1 mL0.24 US fl oz

    For 16 US fl oz of resin at 1.5%.

    Rounded values. 1 mL = 1 cc.

    By volume, not by weight. 1.5%: reference for MEKP 925 at 25°C (77°F). Follow the technical data sheet and batch size limit.

    Use a compatible dispenser, eye protection, gloves and ventilation as specified in the SDS. MEKP is not the solvent MEK.

    MEKP (US fl oz) = resin (US fl oz) × percentage ÷ 100.

    Enable JavaScript to change the amounts. The fixed example shows 16 US fl oz at 1.5%; you can also use the formula above.

  6. Step 6. Mix and apply in time

    Mix evenly using the specified method, including the sides and bottom of the container. Apply within the working time. Do not confuse working time with curing time or the interval between layers.

    Sides and bottom, too

    Apply while workable

    Working time, the interval between coats and final cure are different. Follow the material instructions for each.

  7. Step 7. Handle leftovers

    Do not return catalyzed resin to the original container. If it gels or overheats, stop using it and follow the SDS for handling and disposal. Do not add solvents to restore it.

    Do not return catalyzed material

    Stop using material that has gelled or overheated. Do not add solvent to revive it; follow the SDS for handling and disposal.