Choosing the Best from Epoxy vs Polyester Resin – A Guide to Poly Resin

Updated: 15 Jul 2023


Professional artists and DIY professionals develop more and more uses of resin in daily life routines. Due to its popularity peoples think that resin and its submarine products are the same without any difference. But these are not the same in any intent. If you look two most popular resins in the market name epoxy vs polyester resin. Both look the same but have slight differences in their shapes, usage, and application.

Polyester is a fiberglass resin used in many industries from construction to aerospace. People always wander in compare between epoxy vs poly resin. Both have important roles in construction at an industrial level.

In this blog, you should learn about the best polyester resin, its usage, and all other information.

Closer Look to Poly Resin:

Polyester resin is a famous type of resin also called fiberglass and laminating resin. It is the type of thermosetting polymer produced with the reaction between a polyhydric alcohol and some organic acids. It is called fiberglass polyester resin because most of the time it is cast with fiberglass for strength and more durability and lay-up process.

Poly epoxy is used in the building of boats, repairing swimming pools, pounds, and other production and manufacture that are used in heavy water. These are different from thermoplastics and are recognized as ceroplastic. The material made with duopolistic cannot be remodeled or welded after curing.


This is a budget-friendly and quick-fix resin. It is also less damaged and resistant to chemical exposure.

Polyester is the best choice to fix any repaired surface that has a gel-based substance. It is a common use for sea product repairs like catamarans, boats, and submarines.

While working with polyester resin make sure you wear a respiratory mask. Strong odor makes your breath uncomfortable while working with it. It can be sanded, drilled, and polished according to your need.

Properties of Epoxy vs Polyester Resin:

Synthetic epoxy has many different and unique properties. It always depends upon the application for which we use, its type, and its colorants. It recommends using fiberglass, carbon fiber, and cotton fiber because they make strong durable bonds with it.

The products made with polyester fiberglass are also water friendly. Because it was widely used in water and sea. Strong touch with water makes it food friendly resin. It does not leave any harmful chemicals in water nor change the taste of food.

Polyester epoxy resins are transparent and have excellent strength. Water resistance makes this polymer highly use in the textile and package industry.

Usage of Resin Polyester:

Polyester fiberglass resins have no limit to its usages. It has different uses with liquid, gel, and film coating properties. Engineers, architects, designers, builders, and small repair shops take advantage of this lightweight and waterproof resin in a variety of its application.

Clear polyester is used in swimming pools, ponds, and other outdoor activities that require clear surfaces. It also uses for DIY projects like casting and creating mold. Some other applications like:

  • Boats repair
  • Casting gutters and bumpers
  • Homebuilding or construction materials
  • In the aircraft and sub-marine industry
  • Package material
  • In furniture with strong plastic or cotton fiber

In Construction Materials

Due to its light-weight strength many household items are made with polyester. Shower stalls to closet fixtures are made with polyester fiberglass. Many decorative materials use fiberglass polyester because it makes a strong bond and avails its variety to match with colors.

Automotive, Aircraft, Marine:

Its strong resistance to water and very low weight make it strong and use in water boats, automobiles, and airplanes. Strong durability with plastic or fiber cotton makes it use in racing cars also. The epoxy resin was used to repair boats and submarines when high water retention broke it.

Luggage and Packaging:

It dried well and make a transparent layer to repair package materials. With vacuum and heat technology, packages are sealed with polyester to make a strong seal. Briefcases and suitcases are made with high use of plastic or fiber leather.  

Furnishing and Appliances:

High usage in wet appliances because of transparent properties. Dishwashers to washing machines use fiber to repair them well. Fiberglass did not break well and gives slow or fast curing time depending upon the material and its application.

Resin Epoxy vs Polyester Resin:

Epoxy resins are more expensive because it is more durable and water-resistant. Epoxy is resistant to cracks and peeling, also you can put epoxy products under strong stress.

Polyester resin is used for heavy products because it is a strong material, but you cannot put it under strong pressure or stress.

Pros and Cons of Polyester Resin

Compare with epoxy vs polyester resin has some advantages and drawbacks as well. Some of them are as follows:

  • A variety of materials are available like fiberglass, fiber mates, cotton fiber, and plastic fiber.
  • Less expensive as compared to epoxy.
  • The flexibility of time when working with polyester.
  • Resistant to weather and other changing climates.


  • Strong odor when working with polyester.
  • Not too much strong as compared to epoxy.
  • Produce high odor it is recommended to work outdoors.

Some Best Polyester Resin Products for Projects

While discussing polyester resin we recommended you some products for your project’s better results.

3M Bondo Fiberglass Resin


The best resin that repairs any of your belongings and offers you an ideal durable surface. It ca used as a sealer to bind any old wood to damaged material. A rigid structure is created when working with fiberglass or cotton fiber. It can be used as a gel coat on boats or marine.

The mixing ratio makes it easy to use for any item. The repairing item with 3M is also painted to meet your color mixture. The curing with fiberglass resin bound gives you less odor and is strongly resistant to water. Highly use in submarines use this product in every weather condition.


3M Fiberglass

Check Price


  • Easy to mix
  • Quickly dries
  • Strong use in soft plastic for durability
  • Stable in 2 hours


  • Hard to measure

TotalBoat Epoxy Polyester Resin:


Specially use in repairing boats and submarines with fiberglass or any fiber for strong fixing. Because of its clear surface, you can use it to repair surfboards, bathtubs, and automotive with fibers. This resin is used to create high molds like boats, yachts, and other vehicle parts. It gives a strong and clear base coat on fiberglass or any other fiber. It is water and food-friendly because did not use any wax, and cure in the air. Adding MEKP with different ratios give different cure time.


TotalBoat Polyester

Check Price


  • Need no Sanding.
  • Add MEKP for different Curing times.
  • Easy to use.
  • Use to repair heavy machinery parts.
  • Strong chemical bonding with fiberglass.


  • Store at a low temperature that is 77°F

Bondo Interior and Exterior Use Fiberglass Resin Liquid Hardener:


The liquid hardener is used to repair small items that need extra care like, wallpapers, bathtubs, and wood floors. It gives instant cure and water resistant surface. You can easily use it for your exterior and interior projects. It must stick with fiber and give you a cure with time to make a durable surface. You can also fix your DIY project jewelry and other things with it.


Bondo Resin

Check Price


  • Easy to use and handle
  • Water-resistant
  • Repair most of home hold items like the bathtub etc.
  • Use with resin for fast curing.


  • Cure slowly when used without Fiberglas

Bondo Fiberglass Cloth for Curing:


You cannot work with polyester resin without fiberglass clothes. These clothes make strong bound and allow you to cure quickly. You can cut these clothes into pieces for your use according to size. These clothes are used on every repair item like concrete, wood, metal, and other surface as well. This cloth gives you a waterproof surface and absorbed moisture. It can use to repair boats, tubes, showers, and hot tubes with water-resistant surfaces.


Bondo Fiberglass

Check Price


  • Water-proof
  • Easy to use with the thickness
  • Suitable to use all surface
  • Strong and durable bound


  • Cutting clothes give threads to handle

How to Work With fiberglass polyester:

There are a number of steps involved to work with fiberglass resin polyester. You need to fully prepare the surface before starting your work with resin. You can use any material for cleaning and preparing surfaces for better use.

  • Step for Preparing the Resin: Staring with a clean working environment: Before starting work make sure you have completely cleaned the surface. Remove sand or oil with blur or soft clothes.
  • Add Primer Wax: Add a primer coat to make the resin stay well with the fiber. Primer helps to stay resin within the mold.
  • Mixing Resin with Polyester: Mix an equal ratio of the resin with polyester. Polyester cure slowly if you want to quick cure add some amount of MEKP according to your needs.

Always make sure you clean or even the surface, if you filled doing this it takes extra resin to even the surface. If not cleaned well it will break after some time. If the surface needs any joint, make the joint with fiberglass or with any fiber.

Remove all bubbles if the primer coat has any. If you are preparing mold then remove your material from the mold without any doubt. Polyester resin also uses in the mold to make structures for heavy machinery parts like boats, submarines, and other automotive industries.

Curing time With Polyester Resin:

While working with polyester resin make sure you know well about its curing time and the surface on which we use it. Always read the manufacturer’s instruction label on the product before using it. Other factor curing time includes:

  • The temperature and environment
  • Size and shape of the project.

Temperature Process:

The curing process involves the chemical process. Some polyester is a thinker and cure slowly and some gel resin cure quickly. Typically the resin cure at room temperature like 19°C to 24°C, and some need a higher temperature. In some projects, it cures within 7 days, and in some surfaces, it is cured within 2 hours.

Are You Can Add Color in Polyester Resin?

Just like epoxy polyester has colored during the final finish. Add color to make curing time slow and sometimes it also changes the final shapes and size of projects.

Adding pigments for resin and color design for epoxy in polyester. Before adding any color or pigment make sure you add the exact same shades to get a final result. Because if you add the wrong pigment it affects the final shapes and curing time.

Frequently Asked Questions

Some common question search on SERP for quick information.

What Is Fiberglass Resin?

Polyester resin and fiberglass resin are something’s. Both have slightly different but use for the same items. They use to repair boats, aircraft, jewelry creation, manufacture mold, and many other things.

Can I Mix Acrylic Paint with Resin?

It depends upon your project surface and the material you are using with it. There are also some pigments and dyes for epoxy design to add in polyester. It gives colored furnish to surfaces.

What are the Uses for Polyester Resin?

Polyester epoxy is used to repair boats, air crafts. It also uses sheet molding as the toner of laser printers.

Is Poly Resin the right choice for my Projects?

t depends upon the projects and the size, surface, and other materials. Gel poly cures more quickly than liquid poly. Poly resin is less superior or durable than epoxy but both are used for different projects.

Is Polyester Resin Flammable?

Yes, it is flammable but depends upon the chemical reaction with the material we add to resin and polyester. Always care while working with polyester.

Which is better polyester resin or epoxy?

Although epoxy is superior to polyester. If their moisture is in the air then epoxy is batter. Epoxy also makes a stronger bond than polyester. Over epoxy is stronger and polyester is a polymer of resin. It was always a confusion for picking the epoxy vs polyester.

What are the disadvantages of polyester epoxy resin?
  • It has a Strong Odor.
  • Difficult to mix with two-part epoxy.
  • Use MEKP for quick curing
Is polyester resin epoxy waterproof?

Yes, it offered strong and durable water resistance for a long period of time. It highly uses in marine and boat repair.

How long does polyester epoxy resin last?

It has a shelf-life of ~7 months. After this polyester is harder and makes a hard layer on the surface on which it uses.

What is an alternative to polyester resin?

Vinyl ester epoxy resins are the alternative to polyester resin. Due to its molecular composition, we can divide it into two classes’ epoxy-based vinyl and polyester-based vinyl.


Epoxy and resin both are used in various industries for repairing flooring. Epoxy is used mostly for flooring and finish and it gives quick curing time. Epoxy is used with hardeners to repair different items.

Whereas, polyester resin is a repairing gadget that repairs your boat, surfboat, submarine, and other such heavy materials. People use polyester epoxy for their project experiments because it is much cheaper than epoxy. It is mostly used for outdoor activities that give a clear surface.

Polyester epoxy is mainly used at industrial levels. Follow safety produced while working with it. We hope that this guide gives you all you need to know about polyester resin. Have fun with your project and share it with us cheers.

Nouman Ali

Nouman Ali

Please Write Your Comments