High-efficiency Technology For On-site Epoxy Resin Sleeve Casting With Sponge Sealing
Achieving a leak-proof seal during the on-site casting of an epoxy resin sleeve requires precision and the right materials. When working with critical infrastructure, such as an epoxy bushing for transformer units, the sealing phase determines the structural integrity of the final insulation. Using sponge plugs is a practical, cost-effective method to contain the resin during the curing process.
Strategic Sponge Sealing Process
To ensure a successful pour, follow these technical steps to prepare the interface:
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Clean the Contact Surfaces: Remove all dust, moisture, and oil from the cable or conductor surface.
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Select High-Density Sponge: Use open-cell polyurethane foam with sufficient elasticity to compress against irregular surfaces.
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Positioning the Seal: Wrap the sponge tightly around the base of the casting area, ensuring a 15mm overlap to prevent gaps.
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Compression Fit: Secure the sponge with industrial-grade adhesive tape or mechanical clamps to maintain pressure as the resin expands slightly during heat generation.
Vital Parameters for Casting Success
| Component | Recommended Specification |
| Sponge Density | 25 - 35 kg/m³ |
| Resin Pouring Temp | 20°C - 25°C |
| Minimum Compression | 30% of original thickness |
| Curing Time (Initial) | 4 to 6 hours |
Critical Considerations for Field Installation
Experienced teams know that environmental factors can ruin a perfect setup. Moisture is the enemy of any epoxy bushing manufacturer during the pouring stage. If the sponge retains any humidity, it can cause bubbling or voids within the epoxy resin sleeve, leading to electrical discharge issues later.
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Monitor Ambient Humidity: Keep levels below 70% to prevent chemical interference.
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Layered Pouring: For sleeves exceeding 500mm in height, pour in stages to manage the exothermic reaction.
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Leak Testing: Perform a quick air-pressure check if the mold design allows before introducing the liquid resin.
Professional Maintenance and Inspection
Once the casting is complete and the sponge seal is removed, the surface should be inspected for "bleeding" or uneven edges. A smooth transition between the casted sleeve and the original insulation is mandatory. Most field failures occur because the seal moved during the first thirty minutes of the chemical set. Checking the alignment every ten minutes during the initial pour saves hours of grinding and re-work later. This hands-on approach ensures the longevity of the equipment and maintains the high standards expected from a top-tier epoxy bushing manufacturer.
