Sealing plywood

[Homer J]

Hi Chaps

Can anyone recommend a product for sealing a piece of marine grade plywood - I am using it to support my solar panel across the hatch garage and want to seal it effectively as it cost me a fortune

I have heard epoxy is the stuff to use but what kind and where do I buy it? Can I just use the epoxy that I use for fibre-glassing

The other question is whether i should sheathe the whole thing in fibreglass - I have bought 18mm marine grade which I am hoping will support the panel if someone accidently stands on it - it will be 800mm by 600mm and supported on the short ends by the teak rails for the garage

Any advice gratefully recieved

 

[Tranona]

The weakness in ply is the edges and one way of sealing them is to "paint" with epoxy - the same as you would use for laminating. However the better way is to edge the whole panel with a hardwood lipping glued with epoxy. Then paint the whole panel with a paint system of your choice. Presumably most of the faces of the ply will not be exposed, so a conventional primer/undercoat top coat single pot will be fine.

 

[Caraway]

Hi Chaps

Can anyone recommend a product for sealing a piece of marine grade plywood - I am using it to support my solar panel across the hatch garage and want to seal it effectively as it cost me a fortune

I have heard epoxy is the stuff to use but what kind and where do I buy it? Can I just use the epoxy that I use for fibre-glassing

The other question is whether i should sheathe the whole thing in fibreglass - I have bought 18mm marine grade which I am hoping will support the panel if someone accidently stands on it - it will be 800mm by 600mm and supported on the short ends by the teak rails for the garage

Any advice gratefully recieved

What material is that? Is it epoxy resin? Or is it ordinary polyester resin?
I have sealed sheets of marine ply for floor panels in open boats with epoxy resin. Pay particular attention to the edges and use extra coats there. Then use a UV resistant coating (varnish or paint) over the epoxy.

 

[Homer J]

It’s epoxy resin (I think)

 

[Caraway]

I wouldn't use polyester for your purpose. Epoxy creeps into the grain much better. Best check.

 

[LiftyK]

I restored cabin wood and a flagstaff with West System epoxy and their clear hardener. After this add a few layers of varnish. The West System materials are premium priced but the mixing pumps they use make preparing the resin batch really easy. Perhaps it’s overkill for just one plywood sheet. Learn more at Epoxy User Manual & Product Guide - WEST SYSTEM Epoxy

 

[Kilo]

SP epoxy seems to be identical to West systems & a little cheaper last time I was shopping around. They also do a small pack with pump action dispensers; makes it virtually mess free.

 

[DownWest]

It’s epoxy resin (I think)

Presumable it has a label? Polyester honks of the solvent, while epoxy has a mild-ish smell.
I use quite a lot of epoxy and mix by weight with a kitchen electronic scale, good to a gram.
Since you will have to protect the epoxy from U-V , easiest is polyuethane paint, unless there is some reason to bright finish it.
People speak well of eastcoastresins. Quick delivery.

 

[Stemar]

The thing with most epoxies is that they are attacked by UV, so a good few coats of a suitable varnish or similar will be essential.

 

[Fantasie 19]

The weakness in ply is the edges and one way of sealing them is to "paint" with epoxy - the same as you would use for laminating. However the better way is to edge the whole panel with a hardwood lipping glued with epoxy.

Wise words - my hatch covers have lasted no more than a couple of years despite epoxy coating.. I used what turned out to be cheap and crappy ply, but when I do them again I'd consider hardwood edging..