With its many advantages, epoxy resin can be used in a wide range of fields. Thanks to its exceptional strength and ease of handling, this resin is a flagship product in decoration, jewelry making, and industries such as marine, automotive, and even aerospace. Generally sold as a kit consisting of a resin and a hardener, it adheres to all types of materials and provides a high-quality finish. However, despite its many benefits, unexpected issues can sometimes occur. Improper handling or unsuitable conditions can lead to a few problems. Our specialists are here to help you find the right solution!

Lack of adhesion between epoxy resin and its substrate

In some cases, epoxy resin may not adhere properly to the surface, even though it is usually known for its excellent bonding properties. If you encounter this issue, several explanations can help you understand and prevent it from happening again:

One of the most common reasons for poor adhesion is that the substrate is highly porous. This is the case with materials such as drywall, untreated wood, concrete, brick, paper, or cement. If you plan to apply epoxy resin to one of these materials, it is strongly recommended to apply a second coat—especially along the edges of the surface you want to bond.

Another reason for poor adhesion may be insufficient surface preparation. For example, if you want to coat a wooden surface with epoxy resin, it is essential to sand and clean it beforehand so the resin can bond properly.

Finally, adhesion issues can also result from uneven or inconsistent application. Variations in thickness across the surface can cause the resin to lift or peel in certain areas.

Problems with epoxy resin finishing

When used correctly, epoxy resin provides a beautiful finish, which explains its popularity—especially in decoration. However, some issues may arise during preparation and lead to visual defects. Here’s how to fix them.

Lack of shine in epoxy resin

Epoxy resin normally provides a highly glossy surface. If you notice a dull or cloudy finish, drying conditions are usually to blame. Drying in an environment that is too humid or too cold often leads to disappointing results. However, this issue can be corrected by using an external heat source (such as a hairdryer) to remove excess moisture trapped in the resin.

“Orange peel” texture on the resin surface

A slightly grainy texture resembling orange peel on the surface of the resin is very unpleasant. This effect, which appears after curing, is also caused by unsuitable drying conditions—most often temperatures that are too high or too low. If the resin has not fully cured yet, you can use a roller to smooth out the irregularities. If it has fully hardened, you can sand the surface with abrasive paper. This operation will then require applying spray paint to achieve a smooth, attractive finish.

Appearance of bubbles on the resin surface

Very common, the appearance of air bubbles on the surface is an issue encountered by many epoxy resin users. To prevent this, it is important to carefully mix the resin and hardener. This step should be done slowly and gently to avoid introducing air bubbles. If bubbles appear after curing, they can be removed using a heat gun.

Impurities visible on the resin surface

For an aesthetically pleasing result, the resin must be completely free of impurities, which are immediately visible in this transparent material. To prevent contaminants from spoiling your project, it is essential to keep your workspace clean and to use only containers that have been properly cleaned beforehand.

Epoxy resin does not cure

In some cases, epoxy resin may fail to harden despite mixing the resin and hardener. In such situations, several causes and solutions can be considered:

• Incorrect mixing ratio: To achieve optimal results, it is essential to strictly follow the preparation instructions provided on the product labels. Contrary to popular belief, using too much hardener can actually prevent the mixture from curing properly.

• Low working temperature: Working with epoxy resin at too low a temperature can significantly slow down drying and curing times. To speed up curing, you can use external heat sources such as a heater or a hairdryer.

• Incorrect use of additives: Improper use of additives (colorants or pigments) can also prevent the resin from curing. To avoid this issue, always add additives only after the resin and hardener have been thoroughly mixed.