Sealing ply

[38mess]

I've been given a nice sheet of exterior 18mm ply. I'm using it on part of my wheel house that sometimes gets wet but not soaking. Its exterior ply coming off. It's lasted 36 years so please no lectures about using marine ply?
Anyway the edges are perfect at the moment but I have to cut to fit.
What is the best thing to seal it all, especially the edges, I was thinking two pack?

 

[lustyd]

I usually use epoxy or poly resin. You may find some filler where you cut, if so deal with that first.

My bet is you instead get lectures on how 36 year old ply was amazing and this modern new fangled stuff out of China is hopeless, although you're in Scuttlebutt so may miss the worst of this ?

 

[neil_s]

I would go for epoxy resin. I have found it soaks in better and is a better adhesive, when you come to assemble your new structure.

 

[Poignard]

+1 for epoxy resin. If you warm the plywood the epoxy will soak in further

 

[38mess]

Thanks for all advice.
I have just taken a bank loan and bought some two pack epoxy. That will see me out hopefully

 

[waynes world]

I use warm epoxy resin with a little solvent like acetone aswell as warm the job, this will soak in lot better and add enough layers untill it no longer soaks in. With Poly resin i use styrene if you go that way. epoxy is best though.

 

[Motor_Sailor]

+1 for epoxy resin. If you warm the plywood the epoxy will soak in further

But stop warming it about 5 minutes before you apply the epoxy. You want the ply to be cooling so the air in the wood is contracting and will then draw the epoxy in. If you continue to heat it you will get outgassing where the expanding air makes bubbles in the epoxy as it escapes.

Also don't heat the wood too much. Tropically warm is what you want, not hot. Too warm and the epoxy will kick off too soon and not soak in.

 

[Motor_Sailor]

I use warm epoxy resin with a little solvent like acetone as well as warm the job . . .

Lots of people do, but best practice recommended by West is to do neither. Warming the substrate is the only recommended warm of controlling epoxy viscosity.

 

[waynes world]

Lots of people do, but best practice recommended by West is to do neither. Warming the substrate is the only recommended warm of controlling epoxy viscosity.

this is not structural so a few coats first then others as norm helps.

 

[38mess]

this is not structural so a few coats first then others as norm helps.

Do you mean warm the resins or the ply?

 

[waynes world]

Do you mean warm the resins or the ply?

i always try my best to get the ply and resin to same temp around 15-20 degC

 

[oldharry]

Take great care with fastenings. Any screws or holes you drill will need to be carefully resealed otherwise the moisture will get in, and wick up through the laminates. Once that happens it rapidly turns to cardboard. Rain and spray is just as effectve as immersion if the epoxy seal is compromised.

 

[northwind]

Thanks for all advice.
I have just taken a bank loan and bought some two pack epoxy. That will see me out hopefully ☺

Ahh so you brought West System then... next time buy from Easy Composites..
EL2 Epoxy Laminating Resin - Easy Composites

 

[38mess]

Ahh so you brought West System then... next time buy from Easy Composites..
EL2 Epoxy Laminating Resin - Easy Composites

Now you tell me ☺ £26 from F4?
All done. I just remembered how much I dislike epoxying.

 

[DownWest]

Pity you are not closer, I could have bunged you a litre or so. I scored a 200lt drum + assorted hardeners. Building a small ply cruiser and a friend doing similar with it. Saved a bundle on resin.