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Exotherm, or resin overheating, is a common concern in resin casting projects. Managing your process from mixing to pouring is essential to ensure a safe, flawless finish and prevent warping or cracking during curing.
Understanding Exotherm in Resin Casting
Exotherm occurs when resin cures too quickly, generating excessive heat. This is particularly problematic with thick pours or high-volume projects, where trapped heat can cause defects, discolouration, or even physical damage to the cast. By planning your casting in layers, you allow each to cure safely without risking a dangerous temperature increase.
Step-by-Step Technique to Prevent Overheating
- Follow recommended pour thickness: Never exceed the product’s specified maximum pour depth. For example, EpoxyTable 5-Five is suitable for layers up to 5cm, while Epoxytable 10-Ten can go up to 10cm for large projects.
- Layer your project: Pour a manageable layer and let it partially cure to allow heat to dissipate, then add the next layer. This staged approach ensures even curing and minimises exotherm risk.
- Monitor workspace temperature: Cast resin in a room with stable, moderate temperatures to better control the curing process.
When This Matters Most
Exotherm concerns are heightened during deep pours for tabletops or when embedding objects within thick resin. Artists and makers with ambitious large-cast projects must pay extra attention to layer thickness and wait times between pours to avoid failures from overheating.
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By applying thoughtful layering and choosing a resin system suited to your project’s scale, you can safely avoid exotherm issues and achieve a smooth, reliable finish. For further advice on handling and storage, explore our full guide on how to keep resin from hardening.