Resins, Fillers & Adhesives

This category covers everything needed for GRP (fibreglass) repair and bonding on Irish boats: epoxy and polyester resins, filling compounds for shaping and fairing, and structural adhesives and sealants for jobs ranging from small gelcoat chips to structural, below-the-waterline repairs on hull and deck.

Resin choice depends on the repair. Polyester resin is the cheaper, faster option for cosmetic or above-waterline repairs on a polyester-built hull, but it doesn’t bond well to old, fully-cured laminate. Epoxy resin costs more but bonds far better to existing GRP, wood and metal, absorbs less water, and is the right choice for structural or below-the-waterline repairs – it’s also the only sensible option for osmosis repair work.

Fillers vary by job: lightweight fairing filler sands easily for cosmetic shaping, while structural filler is built to carry load. For bonding fittings, deck hardware or hull-to-deck joints, a polyurethane or MS polymer adhesive/sealant (see our Sikaflex range) gives flexible, waterproof strength without the brittleness of resin alone. Always work above the resin’s minimum cure temperature – an unheated shed through an Irish winter often falls short.

Frequently asked questions

Epoxy or polyester resin for a repair?

Epoxy for structural, below-waterline or osmosis repairs and for bonding to old laminate; polyester for quick, cosmetic, above-waterline jobs on polyester hulls.

What’s the difference between filler and resin?

Resin is the bonding/laminating agent; filler is mixed with resin to build shape, fair a surface or fill a gap, and sands more easily than resin alone.

Can I use epoxy filler over a polyester hull?

Yes – epoxy bonds well to cured polyester laminate, which is why it’s the safer general-purpose choice even on polyester boats.

What’s the difference between an adhesive and a sealant here?

Many marine polymer adhesives (like Sikaflex) do both jobs at once – bonding and sealing a joint – which is why they’re used for deck hardware and hull fittings rather than resin.