Why epoxy resin isn't clear once cured

Epoxy resin is generally known for its ability to provide a clear and transparent finish. However, there are a few reasons why epoxy resin may not appear completely clear once cured:  Yellowing: Over time, epoxy resin can undergo a process called yellowing, where it develops a slight yellow tint. This yellowing can be influenced by factors such as exposure to UV light, heat, or certain environmental conditions. The extent of yellowing can vary depending on the specific formulation and quality of the epoxy resin used.  Air bubbles: During the mixing and pouring process, air bubbles can become trapped in the epoxy resin. If not properly removed or addressed, these bubbles can result in visible imperfections and cloudy areas in the cured resin. Techniques such as using a heat gun, torch, or vacuum chamber can help minimize and eliminate bubbles.  Improper mixing: Incomplete or inadequate mixing of the epoxy resin and hardener can lead to inconsistent curing and cloudiness in the cured resin. It is important to mix the resin and hardener thoroughly, scraping the sides and bottom of the mixing container, to ensure a homogenous mixture and proper curing.  Contamination: Contaminants such as dust, debris, or moisture can interfere with the curing process and contribute to cloudiness in the cured epoxy resin. Proper surface preparation, including thorough cleaning and ensuring a dust-free environment, is essential to minimize contamination.  Incorrect curing conditions : Environmental factors such as temperature and humidity can impact the curing process of epoxy resin. Curing epoxy resin under unfavorable conditions, such as high humidity or extreme temperatures, can result in cloudiness or inconsistencies in the cured resin.  To achieve a clear and transparent finish with epoxy resin, it is important to use high-quality epoxy resin, follow proper mixing and application techniques, and create suitable curing conditions. Taking care to remove bubbles, properly prepare the surface, and provide optimal curing conditions can help minimize cloudiness and ensure a clear result. Additionally, using UV-resistant epoxy resin or applying a UV-protective topcoat can help reduce yellowing over time. Download PDF here