How to Repair Gelcoat Blisters

One of the most striking features of a “new” boat is its smooth, glossy hull. However, gelcoat blisters can ruin this polished look while signaling deeper issues that need immediate attention. Learning how to repair gelcoat blisters promptly can save your boat from extensive damage and keep it looking its best.

What Are Gelcoat Blisters?

Gelcoat blisters form when water seeps through the gelcoat and interacts with the underlying materials, creating a trapped chemical solution. These blisters not only mar your boat’s appearance but can also compromise its performance if left untreated.

Over time, untreated gelcoat blisters can worsen, potentially requiring a complete gelcoat replacement, a costly and time-intensive process. The key to managing gelcoat blisters is early identification and timely repair.

How to Repair Gelcoat Blisters

Follow these steps to repair gelcoat blisters effectively:

1. Drain the blisters: Once your boat is out of the water, use a hard tool like a screwdriver to carefully puncture and drain the blisters. To avoid damaging the surrounding area, apply protective tape around the blisters. Always wear safety goggles and gloves during this step.
2. Grind down the blister: After draining, use a disk grinder to remove the damaged area. Be cautious not to grind too deeply to preserve the healthy parts of the gelcoat.
3. Assess the extent of the damage: Once the blister is exposed, evaluate its size and depth. If the damage is extensive, you may need additional materials and steps to complete the repair.
4. Fill and seal the area: Apply a marine-grade filler to restore the affected area. Sand it down to a smooth finish, and then reapply gelcoat to match the surrounding surface.

Preventing Gelcoat Blisters

The best way to deal with gelcoat blisters is to prevent them from forming. Here are some practical tips:

• Maintain the hull: Regularly clean and wax your boat’s hull to protect the gelcoat from UV damage and environmental wear.
• Inspect during dry dock: Perform routine inspections when your boat is out of the water. Addressing small blisters early makes repairs simpler and less expensive.
• Use a barrier coat: Apply a quality epoxy barrier coat to protect the hull from water intrusion, reducing the risk of blisters.