Epoxy Resin Advice

[jeffstevens763@g]

Originally Posted by Steve509926

Hi Jeff

If I was just doing a straight forward Airdeck/Keel Board replacement I would definitely look towards a composite board.
However, I am attempting to redesigning the front and back keel boards so that they work together and, hopefully, work more efficiently.
I'll post a couple of vids tomorrow which I think will give an understanding of what I'm trying to achieve.

Yea I was shooting in the dark not knowing your exact requirements but sometimes there is other stuff we don’t think about

[GuyC]

Originally Posted by Steve509926

GuyC - why will good quality extetior ply "delaminate pretty quickly almost regardless of how much encapsulation you do"

Whilst marine ply and WBP ply use the same sort of veneers and glues, proper marine ply is void free and this seems to make quite a lot of difference to the quality of the sheet.

WBP ply is OK for interior joinery on a boat but on the outside it seems to suffer.

The encapsulation can be broken down by screw holes (with screws in them), dry bits of fibre wicking moisture for example. There is a school of thought that not encapsulating stuff is better as it has a chance to dry.

You have hit the nail on the head with the "good quality exterior ply" though as they are not all made equal and possibly a good quality WBP sheet and careful sealing would be OK but certainly from my past history, WBP and sea water aren't happy bedfellows.

[beamishken]

I know you want to make the replacement last but remember the boat is a limited life boat & will inevitably go the way most old sibs do & start with failing glue. Robbins elite is probably the best marine ply about but basic wbp well coated with a reasonable yacht varnish will last many years. Pointless spending excessive amounts of money to make the keel last longer than the boat. You could also probably make several replacements of wbp for the price of one from Robbins elite.
My pal owns a fleet of clinker built rowing boats on the river Wear & he builds the hulls with oak ribs & marine ply planking everything else is wbp. Ie anything below the waterline is robbins elite anything above water is wbp. The boats have roughly a 25-30 year lifespan they sit in the water from spring till winter then get a wash & a coat of yacht varnish over winter. He tried west system a few years ago on a couple of new builds & it shelled off with the uv & didnt overcoat very well, he went back to yacht varnish.


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[Steve509926]

Originally Posted by beamishken

I know you want to make the replacement last but remember the boat is a limited life boat & will inevitably go the way most old sibs do & start with failing glue. Robbins elite is probably the best marine ply about but basic wbp well coated with a reasonable yacht varnish will last many years. Pointless spending excessive amounts of money to make the keel last longer than the boat. You could also probably make several replacements of wbp for the price of one from Robbins elite.
My pal owns a fleet of clinker built rowing boats on the river Wear & he builds the hulls with oak ribs & marine ply planking everything else is wbp. Ie anything below the waterline is robbins elite anything above water is wbp. The boats have roughly a 25-30 year lifespan they sit in the water from spring till winter then get a wash & a coat of yacht varnish over winter. He tried west system a few years ago on a couple of new builds & it shelled off with the uv & didnt overcoat very well, he went back to yacht varnish.


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My feelings exactly Ken, it's a SIB and I think overspend and overkill could be very easily achieved, but no matter what ply is used it still needs protection. Hence my post, I've no experience of protecting ply in/on water and my belief was epoxy did the job well, but which epoxy?
20 years of constructing timber framed buildings has given me a good understanding of timber, ply, laminates and how to protect them above ground, and touch wood (see what I did there ) not had a single failure.
If I do go down the route of epoxy, glass, flowcoat /gel it will be more for the experience of doing it. But, I think I will still be using good quality exterior EN636-3 ply.

[jeffstevens763@g]

I’ve done a few bits now console wise I used exterior plywood for sum and marine ply for one both worked you just have to make sure you radius the edges no coating likes sharp right angles any voids I filled with filler.

This is what I followed

https://youtu.be/TzkWeuC0yPs?list=UU...JHt_balZjfseZg

[jeffstevens763@g]

Found this too

https://www.ecfibreglasssupplies.co..../otheruses.pdf

[Steve509926]

Thanks Jeff, two very useful bits of info. Really like that "other uses". Epoxy might become my go too repair material.

[Limecc]

Originally Posted by Steve509926

Thanks Jeff, two very useful bits of info. Really like that "other uses". Epoxy might become my go too repair material.

G-flex 655 is the most flexible epoxy money can buy (pun intended). Even sticks to wet wood, can be used underwater, on difficult to bond plastics and even hypalon or PVC fabrics!

https://www.westsystem.com/specialty...poxy-adhesive/

[909]

SYSTEMTHREE expoxies and fillers work very well.

Okoume Marine plywood pictured above.

[jeffstevens763@g]

Originally Posted by Steve509926

Thanks Jeff, two very useful bits of info. Really like that "other uses". Epoxy might become my go too repair material.

If you ring /email them their tech guy Martin is very helpful even works out quantities with plenty of advice

[Steve509926]

Thanks all for the help and advice. I will be speaking to East Coast tomorrow and be ordering the West Systems epoxy from them.

I have started a new thread (as its not about epoxy) about Airdeck Keel Board Redesign

If your interested this is the link:-

https://www.rib.net/forum/f50/airdec...ign-87561.html