Waterproofing plywood

[rbmatthews]

I need to replace the floor slats in our inflatable dinghy. I have some bits of exterior plywood (not marine) lying around I am planning to use, but would like advice on the best way to waterproof these as much as possible. They need to be a bit flexible without cracking, and I would like to finally paint them grey to match the dinghy.

 

[lw395]

'Exterior Ply' varies a lot.
I've bought cheap stuff from B&Q and it's lasted brilliantly, tried to buy the same stuff again and it's been rubbish.
I would either just use cheap paint and not worry too much, or use an epoxy such as West.
But the cost of the west might be better spent on better plywood?
Have you considered using strips of UPVC or fibreglass sail batten?

 

[rob2]

I'd use a coating epoxy as a primer, which isn't famous for its flexibility but is truly waterproof (compared to other options). Concentrate on the edges where the end grain would otherwise soak water in between the plies. My first choice of finish would be Danboline (bilge paint), possibly not the most hardwearing, but covers well and easy to slap a fresh coat on from time to time. You'll need to lightly sand the epoxy to get a good key.

Rob.

 

[ningcompoop]

The BEST way would be to give them a couple of coats of epoxy, a sheaving with fibreglass then a couple of coats of varnish or paint - not necessarily a quick fix. For example: http://www.robbins.co.uk/Pdf%20Files/sheathing_guide.pdf
Be mindful of voids in the plywood, which would seriously weaken the slats.

J

 

[ribrage]

look for a product called eposeal its an epoxy primer then use paint - it goes on like water and the wood soaks it up like a sponge, it holds together delaminating ply , we've used it to seal a leaky old coach roof numerous times ( in different areas ) as the ply shrank back in the med heat

 

[rbmatthews]

Thanks all for your suggestions. Not sure yet what to go for, but will try and make use of stuff we have already as much as possible.

 

[Habebty]

I just made up some marine ply floor slats for my dinghy and given them 3 coats of Ronseal exterior wood stain so we will see what happens there then!