What You’ll Need

• “Trasparente” – Multipurpose Clear Epoxy Resin for Casting – Up to 2cm: A clear, user-friendly casting resin ideal for detailed coating and potting up to 2cm thick.
• “EpoxyTable 5-Five” – Deep Pour Epoxy Resin for Tables and Large Projects – Up to 5cm: Suited for larger transformers or deep pours up to 5cm to ensure proper coverage and protection.
• Appropriate mould or potting enclosure (plastic, silicone, or other non-stick materials)
• Mixing containers and stirrers
• Protective gloves, safety glasses, and mask
• Digital scales or measuring jugs (depending on the resin’s mixing instructions)
• Release agent (if you need to remove the potted transformer after curing)
• Lint-free cloth and isopropyl alcohol for cleaning

Precise Mixing for Consistent Results

Carefully measure your resin and hardener for each batch—accurate ratios play a vital role in achieving complete curing and electrical integrity in transformer applications. Work deliberately and allow time for bubbles to escape after stirring but before pouring; this step is crucial for optimal insulation.

Step 1: Prepare the Transformer and Workspace

Before beginning, ensure the transformer is completely cool and disconnected from power. Remove any dust, oil, or moisture from the coil and core using a lint-free cloth. If possible, gently bake the transformer (under 60°C) to evaporate any residual moisture, as trapped water can cause failures post-potting. Place the transformer inside your chosen mould or enclosure, securing it so resin can flow freely around all components without air pockets.

Maintain a clean, dry environment throughout this step to prevent later defects. Ensure your workspace is well-ventilated, and all tools are clean and organised.

Step 2: Select and Mix the Resin

Select a resin type based on the transformer size and required protection thickness. For smaller transformers or potting depths up to 2cm, “Trasparente” – Multipurpose Clear Epoxy Resin for Casting – Up to 2cm delivers a crystal-clear, solid barrier. For deeper pours (2-5cm), “EpoxyTable 5-Five” – Deep Pour Epoxy Resin for Tables and Large Projects – Up to 5cm is recommended for its low exothermic reaction and strong mechanical properties.

Carefully follow the manufacturer’s mixing ratios. Use digital scales or accurate measuring jugs as directed. Mix slowly to minimise bubbles, scraping sides and bottom of the container to ensure a homogenous blend.

Choose the right resin for your application to balance ease-of-use and the level of encapsulation needed.

Step 3: Pour the Resin and Eliminate Bubbles

Slowly pour the mixed resin into the mould, starting from one side and letting it flow naturally around the transformer. This reduces the chance of trapping air beneath windings or connections. For deep pours, pour in stages if needed, allowing each layer to settle slightly before adding more to avoid overheating and ensure even curing.

Tap the mould gently or use a pin/needle to pop surface bubbles. If available, a brief pass with a heat gun can help bubbles rise and burst — take care not to overheat the resin or transformer. Work methodically for a smooth, consistent encapsulation.

Manage pour depth and layering to prevent exothermic peaks and ensure a clear result.

Step 4: Cure, Demould, and Inspect

Allow the resin to cure as per product instructions — typically from several hours to overnight, depending on ambient temperature and layer thickness. Keep the transformer undisturbed in a dust-free zone for the duration. Curing times may vary; always consult the recommended guidelines on your chosen resin packaging.

Once fully cured, carefully remove the transformer from the mould if required. Inspect the encapsulation for trapped air and full coverage. The finished transformer should be rigidly insulated and ready for installation or further assembly.

Allow full curing before use to guarantee insulation and long-term reliability.

Tips, Common Mistakes, and Troubleshooting

Always check the ambient humidity and temperature — high moisture can compromise insulation. Never exceed the maximum pour thickness specified by your resin, as overheating or incomplete curing can result. For deep transformers, consider layering your pour to manage heat dissipation. If you notice bubbles after curing, they generally indicate insufficient mixing or incomplete surface preparation. Take time with each step to avoid costly rework.

Choosing a resin with built-in UV filters and mechanical resistance, like those available from ResinPro, further protects your transformer from yellowing and long-term degradation.

Professional Encapsulation Finishes

Patience during curing ensures maximum protection. Epoxy resins with clear, bubble-free finishes greatly increase environmental resistance and reduce future maintenance for sensitive electrical parts like transformers.