Why epoxy resin doesn't fully cure

There are several potential reasons why epoxy resin may not fully cure, including: Incorrect resin-to-hardener ratio: The most common cause of incomplete curing is an incorrect ratio of resin to hardener. Epoxy resin typically requires precise measurements and a specific resin-to-hardener ratio for proper chemical reaction and curing. If the ratio is off, either too much resin or too little hardener, it can result in incomplete or sticky curing.  Insufficient mixing: Thoroughly mixing the resin and hardener is crucial for proper curing. Incomplete mixing can lead to areas of uncured resin or soft spots. It’s important to mix the components together for the recommended duration, ensuring you scrape the sides and bottom of the mixing container to achieve a homogenous mixture.  Cold temperature: Epoxy resin cures through an exothermic reaction, meaning it generates heat as it cures. If the ambient temperature is too cold, the resin may not generate enough heat for the curing process to occur properly. It’s important to work in an environment where the temperature is within the manufacturer’s recommended range.  Moisture or humidity: Moisture can interfere with the curing process of epoxy resin. If the resin is exposed to water or high humidity levels during or after application, it may result in incomplete curing or a tacky surface. Ensure that the working area and materials are dry and that the resin is protected from moisture during the curing process.  Improper surface preparation: The surface to which epoxy resin is applied should be clean, dry, and free from contaminants. If the surface has residues, oils, or dust, it can hinder the resin’s ability to bond and cure properly. Properly preparing the surface by cleaning and ensuring it is free from any debris is essential for optimal curing.  Incorrect curing time or temperature: Different epoxy resin products have specific curing time and temperature requirements. If the resin is not given enough time to cure or if it is cured at a temperature outside of the recommended range, it may not fully cure. Follow the instructions provided by the manufacturer regarding curing time and temperature for the specific epoxy resin you are using.  If you’re experiencing issues with epoxy resin not fully curing, reviewing these factors and adjusting your process accordingly should help improve your results. Additionally, consult the specific instructions provided by the manufacturer of the epoxy resin you are using, as they may offer further insights and troubleshooting tips. Download PDF here