Which is stronger epoxy resin or polyester resin?

Epoxy resin and polyester resin are two of the most common types of plastics used in crafts and DIY projects. Epoxy is tougher than polyester, but the exact strength levels vary depending on the type.

Which one is stronger? Does it matter? To answer these questions, we first need to understand how each type of resin works.

Is epoxy resin stronger than polyester?

The answer is yes, epoxy resin is stronger than polyester resin. However, it does not follow that the more expensive resin will always be stronger than its cheaper counterpart.

This can be explained by the fact that epoxy resins are generally more difficult to work with than polyester resins and have some other shortcomings as well. Here are some advantages of using epoxy over polyester:

  • Epoxies have greater adhesion and chemical resistance compared to polyesters
  • Epoxies have better heat resistance properties than most other plastics

Is epoxy stronger than fiberglass?

Epoxies are strong, and their strength is usually expressed in terms of tensile strength. Tensile strength refers to the amount of force required to break something.

For example, if you were to use a pair of pliers and apply them on either side of a piece of glass until it breaks, the ripping force would be its tensile strength.

Epoxy resins have very high tensile strengths—higher than fiberglass resin or even unhardened epoxy resin (which can be used as an adhesive).

In fact, they’re so strong that they can also be used as structural glues in things like boats or bridges if you want them to hold together forever without getting brittle over time.

Which is stronger resin or epoxy?

Epoxy resin is stronger than polyester resin.

Polyester resin is used in boat building and flooring, whereas epoxy resins are used to coat aircraft, which need to withstand extreme temperatures and other conditions that could harm polyester resin.

Both epoxies and polyesters can be used for this purpose but the difference between the two is that epoxies are usually thicker, harder, and more durable than polyesters.

Does epoxy resin break easily?

You may think epoxy resin is weaker than polyester resin, and that it breaks easily. But that’s not the case!

The truth is, while marine epoxy is strong and durable, it can also be broken if you put enough pressure on it. In fact, if you have ever used a hammer to break something made out of wood, then you know what this means—hammering on a piece of wood until it breaks or becomes damaged is a great way to destroy its strength.

While marine epoxy will expand when exposed to moisture in order to fill any gaps or cracks in an object (similarly to how concrete expands when wet), over time this expansion can cause defects such as delaminations (where layers peel away from each other) or shrinkage features (where material shrinks after drying).

How strong is epoxy?

Epoxy resin is a strong, durable material used to coat fiberglass and build boats and airplanes. It is also used as a glue to bond fiberglass to wood.

Epoxy resin is stronger than polyester resin, but not by much. Epoxy resins have an ultimate tensile strength of roughly 20,000 psi (pounds per square inch), while polyester resins have an ultimate tensile strength of 10,000 psi or less.

Is epoxy resin fragile?

Epoxy resin is a strong, durable resin. It’s stronger than fiberglass, wood, and steel. Epoxy can be used to make bumpers for cars and even airplane wings!

Epoxy resin is also more durable than concrete—which is an extremely strong material that can be found in all kinds of buildings around the world!

Can you put polyester resin on top of epoxy resin?

Sometimes people ask if they can put polyester resin over epoxy resin.

The answer is no, because they’re different materials and can’t be used together.

However, Polyester resin can be used on top of itself. If that’s what you need to do, then go right ahead!

Can you mix epoxy and polyester resins?

You can mix epoxy and polyester resins to make a composite, laminate, or part. Mixing the two resins is not difficult as long as you follow some simple rules.

Let’s take a look at what happens when you mix the two types of resin together:

  • Epoxy – Epoxies are usually stronger than polyesters but they are not very flexible. Therefore, if you mix them with polyester resin, the epoxy will help increase the flexibility of your finished product while retaining its strength.
  • Polyester – Like epoxies, polyesters are often stronger than their counterpart but they can be more brittle because of their lack of flexibility (compared to epoxies). When you combine them with an equal amount of clear hardener and fiberglass cloth (or other reinforcement), then this may reduce some brittleness issues while increasing strength overall


In conclusion, epoxy resin and polyester resin are both strong adhesives. However, when it comes to using them for practical purposes, epoxy is stronger than polyester because it has more adhesive power (or “cohesion”) than the latter.

That being said, both epoxy and polyester resins have their own respective strengths: epoxies are good at bonding metal while polyesters are suitable for woodworking projects like building furniture or cabinets!

Leave a Comment