Deck/Shroud Fixing/Fibreglass repair.

[davidpbo]

The old Mahogany should be fine, but will need several coats of epoxy resin (wet on tacky to avaid sanding between coats) make sure you lots into the end grain edges and round them off before wetting.

Good luck and fair winds.

Would I have to do the same with marine ply or is it because of natural oils in the wood?

 

[oldsaltoz]

After 20 years I doubt the mahogony will be a problem, and yes, you will have to seal the marine ply if used.

The coating will prevent water rottong the ply in the future.

Any holes through the ply must be drilled oversize by at least 10mm and filled with a mix of epoxy resin and Micro-fibres, this will support the ply and again prevent moisture entry.

Good luck and fair winds.

 

[davidpbo]

Can I use the colloidal silica to to thicken the adhesive and fill gaps?

 

[oldsaltoz]

Can I use the colloidal silica to to thicken the adhesive and fill gaps?

Yes it's fine for gap filling but you need fibres to make a good adhesive, as I understand it you have two areas to fill.
The internal gap and the hull to deck joint.

The hell to deck needs fibres to add strength.

Good luck and fair winds.

 

[davidpbo]

All I have to fill is any gap between the core wood to deck, cabin ceiling to core will be laminated onto core from underneath.

There might be a bit of gap filling around the sides of the wood where it buts up to the existing balsa core and where the core buts up to the very solid filler edging the hole under the remaining deck fibreglass where the core has been removed towards the deck hull joint.

 

[oldsaltoz]

All I have to fill is any gap between the core wood to deck, cabin ceiling to core will be laminated onto core from underneath.

There might be a bit of gap filling around the sides of the wood where it buts up to the existing balsa core and where the core buts up to the very solid filler edging the hole under the remaining deck fibreglass where the core has been removed towards the deck hull joint.

If I did this work the joint would have epoxy resin and fibres as well as holes drilled on a 50mm grid to ensure no air is trapped.

Any holes drilled after this would be drilled oversize and filled with resin and fibres the re drilled to the required size.

Good luck and fair winds.

 

[davidpbo]

Given that the repair is around the shroud fixings I don't mind if it stands proud, it may be better than trying to get it flush. If I went for that approach how far outside the existing holes should I take the final layers and how many layers of mat ( I have woven) should I use over and above the existing layer of skin.

Something like where the line is on this photo?

Full album here

 

[davidpbo]

Well folks, I have started the fibreglassing today.

Using SP Epoxy and West systems woven cloth. Bought a piece 1M by 1m which with what I had I thought would be enough but I am suprised at the number of layers I have to use. Each layer about 0.2mm without resin, the depth of fibreglass I have to build up is about 3mm. Should I be using thicker rovings interspaced.

So far I have coated and fitted the wood cores (know this one needs sanding before I start applying fibreglass) and built up maybe 6 or 7 layers on one side and have used the 1Kg of SP epoxy I bought.

 

[oldsaltoz]

Well folks, I have started the fibreglassing today.

Using SP Epoxy and West systems woven cloth. Bought a piece 1M by 1m which with what I had I thought would be enough but I am suprised at the number of layers I have to use. Each layer about 0.2mm without resin, the depth of fibreglass I have to build up is about 3mm. Should I be using thicker rovings interspaced.

So far I have coated and fitted the wood cores (know this one needs sanding before I start applying fibreglass) and built up maybe 6 or 7 layers on one side and have used the 1Kg of SP epoxy I bought.

It sounds like you are using way too much resin.

You are looking at a ration of 1 to 1 resin to cloth, so roll out the excess resin or the job will be weaker than if rolled out properly.

Roll, roll, roll.

Good luck and fair winds.

 

[jwilson]

Making a mould with some silicone is not difficult.

Find a good piece of deck, make a dam with plasticine, paint deck with mould release, spray was will do, pour in some moulding silicone. [ Silicone sealer will do at a pinch.

Use mould to replicate deck pattern.

A yard which builds very expensive GRP yachts had to do this on 2 parts of my deck after they damaged some of the visible gelcoat getting a sikaflexed-on toerail off as an insurance repair. The joints between the new moulded bits and the original deck are still very obvious, despite two goes at the job. Was not a happy bunny as if they'd taken more care getting the toerail off the damage would not have happened.

For the original poster, after making sure the (hopefully ply) core of the deck around the U-bolts is dry, I'd fit a S/S plate externally over the cracked areas. It will look better than a visible joint in a textured deck.

EDIT - Posted this before seeing that you'd already cut out a section of the deck..........

 

[davidpbo]

It sounds like you are using way too much resin.

You are looking at a ration of 1 to 1 resin to cloth, so roll out the excess resin of the job will be weaker than if rolled out properly.

Ro;;, roll, roll.

Good luck and fair winds.

Hi oldsaltoz, thank you for inputs, drilled the wood as you suggested and fitted it without problem. Thanks for the tip.

I don't think I have any excess resin on the cloth, some of the same resin was used with microfibres fitting the wood cores.

For the original poster, after making sure the (hopefully ply) core of the deck around the U-bolts is dry, I'd fit a S/S plate externally over the cracked areas. It will look better than a visible joint in a textured deck.

EDIT - Posted this before seeing that you'd already cut out a section of the deck..........

One of the options I was considering until I saw the rot and had to investigate the extent of it.

Having taken a couple of weeks since the opening the damaged area, the remaining core has dried out nicely.

 

[davidpbo]

Hello, I am now at the stage of the bit that can be seen, I am using flowcoat from a resin supplier. Had a bit of set back when the first coat on one side did not go off, probably due to too little catalyst.

I now have one coat on one side and two on the other, how many should I aim for ?

 

[davidpbo]

Thank you all for the assistance with this. The repair was completed, the finish is ok but not great.The plan is to add a few more coats and sand and polish.

Been out sailing from Pwllheli, it seems ok, time will tell.