Measurement System
Sets the units used throughout.
The resin doesn't care which system you use — only that you pick one.
Ambient Temperature
Shop or on-water temperature at time of mixing.
Resin / Gelcoat Volume
How much material you are catalyzing in this batch.
MEKP Percentage
Lock to the Duratec ratio, or dial in your own.
Mix Result
Add this much MEKP catalyst
—cc
≈ — drops
Recommended MEKP % (based on temperature):
Using slider value:
MEKP CCs:
MEKP Drops:
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How to Use the MEKP Calculator
MEKP (Methyl Ethyl Ketone Peroxide) is the catalyst used to cure polyester and vinyl ester resins. Getting the ratio right is critical — too little and it won’t cure; too much and it cures too fast or becomes brittle.
- Enter resin volume — Type the amount of resin you’re mixing in the volume field and select your unit (oz, qt, gal, mL, L).
- Enter temperature — The calculator adjusts the recommended MEKP % based on ambient temperature.
- Check Duratec (if applicable) — Locks MEKP at 2% for Duratec 904-001 Hi-Gloss Additive.
- Read the result — Results update automatically. You’ll see the MEKP amount in both CCs and drops.
Key facts
- Hot weather (85°F and above): Use 1% to extend pot life.
- Cold weather (<65°F): Use 2.5% from 60–65°F and 3% below 60°F to ensure full cure.
- Never exceed 3% — excess MEKP weakens the final laminate.
Tips & Safety
MEKP is an organic peroxide. Read these before you open the bottle.
Other Calculators
More mixing tools for hull, deck and topside work.
- Fiberglass Cloth Saturation Calculator Resin and cloth quantities by laminate schedule
- Awlgrip Coatings Calculator Base, converter and reducer ratios
- Epifanes Polyurethane Paint & Varnish Calculator Two-part mixing for brush or spray
- Alexseal Yacht Coatings Calculator Topcoat and primer mixing ratios for spray or brush