How much hardener to polyester resin. Ensure proper curing with ChemCalc's free MEKP calculator. 75% (1 2/3 ounce to 2 1/3 ounces per gallon). Mix Ratios: a. . its the same as a babies medicine spoon. Polyester resin requires MEKP hardener. Mix with resin only once you are ready to apply it. Maximize your epoxy projects by understanding the perfect ratio. For example, four drops of hardener will be 1 percent of 1 ounce of resin. If you forget the hardener, the laminated surface will never harden or hold. If you’re struggling to thoroughly mix epoxy resin, you won’t succeed in mixing polyester casting resin. May 21, 2025 · Learn how to mix resin with hardener correctly to avoid bubbles, uneven curing, and sticky messes. This indicates how many parts hardener 100 parts resin need to cure. Resins that have Duratec in their name require a 2% mix ratio (2 2/3 ounces per gallon). MEKP Chart and Calculators. 5%. I have seen some at 4 to 1 and 5 to 1 , but never heard of a 1 oz to 1 gallon ratio. Polyester resin is recommended for use with fiberglass repairs that are above the water line on boats and also on other dry-surface fiberglass forms such as auto bodies and models. What is the hardener in polyester resin? Catalyst What is Polyester Resin? Polyester resin is an excellent matrix material in the creation of fibreglass (GRP) in the presence of a catalyst and combined with glass fibre chopped strand matting (CSM). Methyl ethyl ketone peroxide (MEKP) is an organic peroxide used in the marine industry. It is typically used between 1. It has a quick cure and adds dimensional stability. May 30, 2018 · Ratio The ratio range for catalyst to resin is 1 to 2 percent hardener to the total volume of resin to be used. Be certain to stir the catalyst in thoroughly or part of the resin will be undercured, weakening the lay-up. It is affordable and easy to use. Polyester resin is most commonly used in the manufacturing of boats, surfboards, kayaks and other nautical vessels. It is used in a wide variety of projects including boats, car bodies, kayaks, surfboards, patio decks and aircraft. How much hardener should you add to polyester casting resin? The amount of hardener you add to polyester casting resin is dependent on the depth of the final casting. Follow our simple step-by-step guide. The hardener ensures that the polyester resin reaches its final hardness after a certain curing time. On this page we explain to you what the mixing ratios of these resins are and how to mix both components correctly! Mixing Polyester Resin, Topcoat and Gelcoat Polyester-based products (polyester, topcoat, gelcoat) are generally cured with a MEKP polyester hardener. This is because thin layers are unlikely to generate enough heat to cure. For small quantities (< 5 ml) of hardener, use a pipette. Don't mix too much polyester resin. Jul 25, 2025 · Unsaturated polyester resin (UPR) is one of the most widely used resins across various industries—from fiberglass production and marine components to mold-making, artificial stone manufacturing, and even crafts and decorative arts. 5 to 2ml catalyst. May 30, 2025 · What Is the Resin Calculator? The Resin Calculator is a practical tool for planning epoxy resin projects. Approximately 2% hardener is added to polyester resin. Jul 8, 2009 · Polyester resin usually requires 1 to 2 percent of hardener by volume (follow the manufacturer's instructions). When preparing to perform a repair, you must mix the proper ratio of hardener to polyester resin to prevent the resin from failing to cure properly. Below are two FREE MEKP Calculators and a MEKP CHART to simplify the process of determining the proper ratio of resin to catalyst or gelcoat to catalyst. Catalyst Chart for polyester resin, gel coat and vinyl ester marine resins. CATALYST LARGE QUANTITY CHART Catalyst Concentration Resin Quantity Quart Gallon 5 Gallon 1/2% 1/16 oz 2/3 oz 3 1/3 oz 3/4% 1/4 oz 1 oz 5 oz 1% 1/3 oz 1 1/3 oz 6 2/3 oz 1 1/2% 1/2 oz 2 oz 10 oz CATALYST SMALL QUANTITY CHART CatalystConcentration Resin Quantity30 drops = 1 cc 2 oz 4 oz 8 oz 12 oz 16 oz 1/2 % 9 drops 18 Mar 20, 2018 · Learn how to measure and mix resin and hardener with our comprehensive guide. If you use too much hardener, the polyester resin will become very hot and start to smoke as the hardener and resin undergo a chemical reaction. Whether you're crafting a river table, applying a surface coating, or casting in molds, this tool helps you figure out exactly how much resin, hardener, and optional additives you'll need. Mix resin and hardener carefully and scrape bottom and sides of the Usually, mixing ratios of epoxy resin are given as 100:XX. Once mixed, these two parts make a chemical reaction so your resin is pourable and will cure to a hard, clear, glossy finish. tube of liquid hardener (MEK Peroxide) is sufficient to harden the entire contents of a gallon container. How do you make polyester resin? Never prepare more polyester resin than you can process in 10 minutes. Try for FREE! MEK, short for MEKP, is the “Hardener” or catalyst for Polyester Resin and Vinylester Resin Systems including Isothalic and Gelcoat. Determine the amount of hardener according to the ambient temperature. MEKP, or Methyl Ethyl Ketone Peroxide, is a clear catalyst (hardener) added to gelcoat, polyester resin, and vinylester resins. CATALYST LARGE QUANTITY CHART Catalyst Concentration Resin Quantity Quart Gallon 5 Gallon 1/2% 1/16 oz 2/3 oz 3 1/3 oz 3/4% 1/4 oz 1 oz 5 oz 1% 1/3 oz 1 1/3 oz 6 2/3 Calculate the precise amount of MEKP catalyst needed for polyester resin or gelcoat based on volume and temperature. Needed Supplies (this will vary depending on The resin to hardener mixing ratio will be so much of part a, (the resin) mixed with so much of part b (the hardener). of Fiberglass Resin (or for 1⁄4 can of Fiberglass Resin, use 1⁄4 tube of liquid hardener). TIP: You can also use these to calculate the correct amount of Wax Additives or other surfacing agents How much hardener should you add to polyester casting resin? The amount of hardener you add to polyester casting resin is dependent on the depth of the final casting. Using the correct ratio is very important Feb 28, 2007 · the colder the tempature is the more % of mekp you will need,I always use the chart of the CC wich is much easier and accurate. 25% to 1. The dosage of this transparent hardener may be between 1. Because of its easy application and durability, polyester resin is also applied to patch cracks and holes that need to remain watertight. Typically used in ratios between 1-3%, use MEKP sparingly! Mixing large Nov 24, 2023 · Learn the exact steps on how to mix resin and hardener with this easy-to-follow guide. Jul 18, 2007 · Re: Resin to hardener Ratio It varies by manufacturer I don't know about ploy resin , but regular epoxy is usually measured in ratios and I use a 2 to 1 part mix. 50 % of mekp 59 degrees and below = MEKP is a clear hardener/catalyst for the room temperature cure of unsaturated polyester and vinyl ester resins. One of the key success factors in using polyester resin lies in its correct and precise mixing ratio with the hardener (catalyst). Perfect for beginners looking to create stunning resin projects! Polyester laminating resin, also known as fiberglass resin, is the most commonly used resin in the industry. It is also needed with all gel coats. Fibreglass Resin: for 100ml of resin (cold day) use 2. 5% and 2. 25% of mekp 60 degrees to 69 = 1. 2. It has many applications and is notable cheaper and easier to use than other resin systems. Not sure how much epoxy you need? Then check out our article on epoxy quantities needed. What is the mix ratio for fiberglass resin and hardener? A 2 oz. Expert tips and step-by-step guidance for DIY enthusiasts and professionals. It seems counterintuitive, but the thinner the casting, the more hardener is needed for curing to occur. CATALYST LARGE QUANTITY CHART Catalyst Concentration Resin Quantity Quart Gallon 5 Gallon 1/2% 1/16 oz 2/3 oz 3 1/3 oz 3/4% 1/4 oz 1 oz 5 oz 1% 1/3 oz 1 1/3 oz 6 2/3 May 30, 2018 · Ratio The ratio range for catalyst to resin is 1 to 2 percent hardener to the total volume of resin to be used. What is the hardener in polyester resin? Catalyst Learn how to properly mix polyester resin with hardener and understand the drying times for optimal results. Adding MEKP causes a reaction that cures resin at room temperature. As a rule of thumb, four drops of hardener will catalyze 1 ounce of resin at 1 percent. Oct 23, 2023 · Polyester casting resin does not mix in a 1:1 or 2:1 formula but instead requires drops of hardener per ounce of resin. Estimate the amount of resin needed to completely saturate the fiberglass material, pour the resin into a clean container (paper cup or metal can) and follow by adding the proper amount of liquid hardener. This article provides an in MEK, short for MEKP, is the “Hardener” or catalyst for Polyester Resin and Vinylester Resin Systems including Isothalic and Gelcoat. Add 14 drops of liquid hardener per 1 oz. 5 to 3ml catalyst; and for 100ml resin (hot day) use 1. ex: 90 degrees and higher = 1% of mekp 70 degrees to 89 = 1. Polyestershoppen mixing ratios Polyestershoppen helps you find the correct epoxy mixing ratios. 3eat vj5l e95n3 hdlc xmb zfo 5b1 spgt wo 4fwk