Polyester Resin Mixing Instructions


Polyester resin is the most common type of resin in the marine industry. It’s perfect for low-cost repairs and new construction parts. Our polyester resin is great on vertical surfaces and also works great for fast glass wet out because of its low viscosity. This resin must be catalyzed with MEKP (Methyl Ethyl Ketone Peroxide) to properly cure. Our general purpose polyester resin is great for a wide variety of applications including, hand layup by brush or roller, spray on applications, marine, transportation, auto body, aerospace, general purpose laminating, FRP parts and more. This resin is compatible with all types of fiberglass and coring materials. Because this resin contains a styrene monomer it is not compatible polystyrene foam.

Mixing Directions:

Resin should be agitated before use. MEKP hardener should be mixed at a recommended ratio of 1.5% by weight. For easy measuring use 1.5 teaspoons of hardener per pint of resin, 3 teaspoons per quart, and 11 teaspoons per gallon. For smaller quantities use 13 drops per ounce of resin. Always be sure to measure your components, never guess them ever. Mix thoroughly for 3­5 minutes using a mixing paddle. Be sure to scrape the sides and bottom of the container while mixing.

At a temperature of 77°F, your resin will begin to harden and gel in about 20 minutes and will be sandable in 6 hours. Total cure time is 24 hours. When the temperature is colder the resin will take longer to harden and when the temperature is hotter it will take less time. If you need to adjust the working time of the resin this can be achieved by altering the catalyst ratio. The range of catalyst you can add is between 1% and 2%, no more and no less. Altering the ratio is not recommended for beginners as it can cause the product to become unstable if measured and mixed incorrectly.

Never use this resin in temperatures below 60°F. If temperatures are above 85°F only mix small batches at a time as the resin will cure very rapidly. Never use this product in direct sunlight. Always use clean plastic, glass, paper, or metal mixing containers. polystyrene will melt when in contact with the resin so avoid using foam cups for mixing. Mix only what you need at a time and never return any unused (catalyzed) resin to the original container.


Surface Preparation:

Clean the area with acetone and let dry completely. Sand the area with no finer than 80 grit sandpaper and wipe the area with acetone before lamination. Make sure you remove all loose paint, primer, and other debris. For direct to wood applications apply a thin coat of resin to the wood and allow to cure for 1 hours then follow up with additional layers of fiberglass and resin. This ensures penetration to wood and proper adhesion to your surface before laminating. You have 4 hours between coats otherwise sanding will be required.




Keep out of reach of children. The product should be stored in a closed container at room temperature. The uncatalyzed resin can be mixed and stored in a closed container at room temperature between uses. Mix thoroughly before catalyzing.


Safety and Handling:

These products are capable of producing adverse health effects, ranging from minor skin irritation to serious systemic effects. Exposure to these materials should be minimized and avoided, if feasible, through the observance of proper precautions, use of appropriate engineering controls and proper personal protective clothing and equipment, and adherence to proper handling procedures. None of None of these materials should be used, stored or transported until the handling precautions and recommendations stated in the Material Safety Data Sheet (MSDS) for these and all other products being used are understood by and all other products being used are understood by all persons who work with all persons who work with them.


Typical Liquid Properties (77°F)



Brookfield viscosity (RVT #3 @ 50), cP


Thixotropic index (RVT #3, 5/50 rpm)


Gel time (minutes), 1.50% DDM­9


Gel to peak time (minutes)


Peak exotherm (°F)


HAPS content by weight (%)


Total VOC content (%)


Was this article helpful?
0 out of 0 found this helpful
Have more questions? Submit a request



Article is closed for comments.