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Proper surface preparation is vital when working with fibreglass and epoxy glues. Sanding and degreasing surfaces before application ensures maximum strength and a professional finish.
Why Sanding and Cleaning Matter
Bonding fibreglass, carbon fibre, or most composite materials depends on more than just the right adhesive—it starts with prepping the surfaces. Sanding roughens the area to help the glue penetrate and anchor itself, reducing the risk of peeling, delamination, or weak spots. Every trace of grease, dust, or old paint can disrupt this process, leading to poor adhesion and compromising repair integrity.
How to Prepare Surfaces Effectively
- Sanding: Use medium-grit sandpaper (typically 80–120 grit) to abrade the area. Ensure you remove any gloss, old coatings, and surface imperfections.
- Cleaning: After sanding, wipe down the surface with a pure solvent like acetone or isopropyl alcohol. Repeat as needed to ensure there is no residue left.
- Dust removal: Clean away sanding dust using a lint-free cloth before you mix or apply adhesives such as epoxy resin for carbon fibre and fibreglass or specialist repair kits.
When This Matters Most
Surface preparation is especially important for repairs subject to stress, vibration, or moisture—such as boat hulls, car panels, or pipe joints. Neglecting sanding or degreasing can lead to premature bond failure in these challenging conditions.
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Taking the time to sand and degrease surfaces is an essential step when using fibreglass, epoxy, or composite repair products. For more guidance on successful bonding techniques, see our advice on using fibreglass and epoxy glue.
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