A retired friend owns a cabin cruiser with a cockpit roof made from marine plywood. Late last year he employed a company to 'fibreglass' the outside to give it protection from the elements. He has now found that the 'fibreglass' has delaminated and has asked me to fix it. I am a carpenter but I did get the chance to use fibreglass at school (making model boats from a wooden mould) but that was a good many years ago! No doubt things have changed a lot since then.

Searching the web for these symptoms suggests that polyester resin was used, not epoxy. So the questions now are:-

1. Is there an easy way to tell what resin was used? One site suggested sanding the cured resin and smelling for the characteristically sweetish smell of polyester resin, or a more pungent smell of epoxy. Are they right?

2. If it is polyester that was used, should I strip it all off, back to the bare wood, then recoat with epoxy resin?

3. Which of your products would you recommend and what quantity? The roof is approx. 2m x 2m.

4. Should I incorporate a glass mat into the resin, or would it be strong enough just bonded to the plywood?

5. Any other tips, suggestions or recommendations would be appreciated.

Many thanks,

Paul - Woodcrafts

1.  If you can't smell any styrene then you will struggle to identify it based on smell. With it weathering for half a year I would imagine the resin to be fully cured now. Epoxy resins are mostly low odour.
2.  In most cases of severe delamination you will need to strip it back and start again. To achieve best results you will need the whole thing to have dried out properly.
3.  Our EL2 Epoxy Laminating Resin will be more than upto the job especially if you are laying on some woven glass or similar.
4.  If you are looking to strengthen the cockpit roof, then yes some fibreglass will help.  It will also help with smoothing out a rough surface.  What finish are you trying to achieve? is it to be painted?
5.  You will need the surface properly roughed up to achieve the best bond possible.  You will need to work at a temperature not lower than 15 degrees Celcius or you will struggle to get the resins to cure in a reasonable time.


Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant