Renewing gelcoat does not always make sense


Unlike conventional paint finishes, it is important to check carefully how well it has bonded to the fiber reinforced plastic prior to renewing the gelcoat. If both materials form a homogeneous body, renewal is often just a matter of applying a new layer that does not eliminate any structural damage.

Power and elasticity

Gelcoat always assumes a reciprocal relationship with the fiber-reinforced plastic it covers, assuming the right processing. While gelcoat can be renewed on garden furniture or other household items without direct impact mostly by simple sanding and new H, this is not so easy with boat hulls.

Damage to the gelcoat, which leads to the desire of renewal, usually arises in conjunction with the substrate. Typical damage forms arise from different elasticities. If the substrate has more elasticity than the gelcoat, cracks inevitably occur. When renewing this cause must be excluded by adjusting the elasticity values.

Osmosis, sources and remediation

Another major cause of gelcoat damage to ships and boats is the effect of osmosis. The constant watering and the resulting moisture molecules attack both the gelcoat and the plastic underneath. Leaching of the resin leads to softening and loss of stability of both materials.

Added to this is the swelling behavior of the fiber-reinforced plastic, which in turn conveys the tearing of the gelcoat. The osmotic process is beyond a certain operating time of a boat, and restricted even in RVs, no longer prevent. Usually only a few years of use can be achieved by renewing the gelcoat.

It is essential to check the static condition of the entire hull. A complete renovation is only worthwhile in a few cases and must be carried out by a specialist company. The prices for renewing or renovating an osmosis damage are between 1,000 and 1,500 euros per boat meter only for the, under water, hull part.

Tips & Tricks

If you have hands-on experience with the materials and additives that are found in fiber-reinforced plastics and gelcoat, including additives and hardeners, you can optimize processing by sandblasting the boat hull.


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