Choosing Between Fibreglass, Putty or Epoxy for Crack Repair

Understanding Your Repair: Depth and Stress

Start by assessing the crack’s depth and the stresses the area will face. For surface-level cracks or dents, especially where flexibility is needed, a fibreglass-reinforced putty such as CROP 2K Fiberglass Putty is ideal. Its polyester base reinforced with fibreglass fibres fills and smooths cavities, providing added strength and moisture resistance.

For more substantial cracks, especially in load-bearing or structural components, a fibreglass repair kit offers robust reinforcement. The Resin Fibreglass Repair Kit combines a fibreglass mat with polyester resin, creating a durable, waterproof bond suitable for repairs exposed to water and heavy use.

When to Use Deep Pour Epoxy

If your project demands a clear, thick, seamless finish—such as table pours, large castings or fills over several centimetres—a deep pour epoxy is the right choice. Products like EpoxyTable 5-Five are formulated for pours up to 5cm thick, controlling heat build-up to minimise cracking. For even deeper castings (up to 10cm), use a specialist deep pour epoxy and always pour in multiple layers for safety and to prevent defects.

Unlike putty or fibreglass, epoxy’s main advantage is its clarity, strength and the potential to create a level, bubble-free surface in large volumes.

When This Matters Most

• Boat, pool, or pipe repairs: Use reinforced fibreglass kits for waterproof, structural fixes.
• Automotive and bodywork: Opt for fibreglass putty for easy filling and sanding.
• Creative builds or furniture: Choose deep pour epoxy for thick, transparent finishes and artistic results.