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Thinning polyester resin beyond recommended instructions can actually weaken its performance and compromise your finished project. Let’s explore why keeping to the right mix matters, how to apply resin correctly, and what to use for the best results.
Why Not to Over-Thin Your Polyester Resin
Polyester resin is formulated to deliver robust water resistance and structural strength after curing. It’s tempting to add solvents or extra additives to make it runnier or stretch it further, but modifying the kit’s instructions can reduce adhesion, durability, and waterproofing. Using too much thinner often leads to a brittle, weak repair or uneven surface.
Correct Mixing and Application
Most reputable repair kits, such as the Resin Fibreglass Repair Kit – Complete Polyester Resin and Hardener Set, are supplied ready-to-use. Follow the included instructions for combining resin and hardener in the specified ratios—no dilution needed. If you require better flow, simply mix thoroughly and work at a suitable room temperature, which helps maintain a manageable viscosity.
When This Matters
Avoiding over-thinning is especially critical when carrying out structural repairs, such as fixing boats, pools, or pressure pipes. Thinned resin might seem easier to apply, but will not offer the lasting, waterproof bond required for such demanding tasks.
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For robust, worry-free repairs when using polyester resin, always stick to the recommended mixing and application. Explore our full guide on how to dilute polyester resin for more expert tips and product advice tailored to your project.