[zzxswqq]

When it comes to defining “marine grade,” manufacturers often use the term too liberally to be truly helpful. In order for a product to bear the title “marine grade,” technically, it doesn’t have many requirements over your typical exterior-grade plywood (according to the APA). So if you require a product that will stand up to being submerged in water, don’t make the mistake of thinking anything that bears the name “marine grade” will work well; it might, but it might not. Many factors — including glue, preservatives, plies, core construction, veneer core species, and face veneers — combine to determine the level of water resistance that a sheet of plywood offers. more

[coins]

In addition to veneer core, MDF core, and architectural plywood, J. Gibson McIlvain also carries two types of marine grade plywood. When discussing marine grade plywood, the first thing we need to do is to define the term “marine grade.” Many customers mistakenly believe that their projects require waterproof plywood when they actually don’t. Marine grade plywood is a waterproof product intended for exterior uses that will typically do more than come into contact with water but will in all likelihood be completely submerged. There are many projects that may require plywood that’s water resistant; however, few require waterproof marine grade plywood.

[nephishe]

What does plywood have to do to earn the term “marine grade”? In order to be considered marine grade ply, a product must have a core that’s free of voids which could trap water, causing the product to rot from the inside out. For the same reason, few repairs to the core plies are allowed. The glue used must be Weather and Boil Proof (WBP), which has proven to hold up to boiling water for over an hour, without delamination. more

[Vaschel33]

It sure would be simpler if only plywood suitable for boat building were allowed to carry the label of “marine grade.” The boat building industry has special requirements for optimal water resistance as well as for bending ability and appearance. Plywood that’s suitable for boat-building must have a consistent face or “show face,” along with the ability to operate reliably for fiberglass overlay or a decking veneer. Weight is also an issue for many boats. The level of water-resistance required for a boat’s exterior should be BS108 or better, in order to ensure durability over the long haul.

[happyrlt]

I'm kinda confused here.
I already put the carpet down so the top deck is how it is, but should i apply a sealant to the underside of the decking?? [links]

[QuantumMechanic]

I'd like to do the project correctly and get 8 years out of the deck if possible. I leave the boat in the water at our dock for the summer 4 months, but when it's not in use will have it's cover on, and in the winter it's fully covered up and sheltered.

[vhaugn143niels]

My question is should I be adding some kind of sealant to the wood? The deck is Marine Grade 3/4 plywood that is not pressure treated (because of the reaction to aluminum). I sealed all the bolt holes with caulk and sealed between the sheet gaps and i also rubbed some caulk around the edges of the wood. I also laid down rubber weather stripping on all the cross members that the wood will rest on. I did not "seal" the wood though. I have read many posts on people saying that: here

[dbwinbonuss]

I just finished re-decking my project pontoon. After finding out my deck was not as good as i previously thought, i figured it was better to just replace it instead of putting nice carpet over junk wood. i will add some pics. more

[30dirtybirds]

-Marine plywood should be left unsealed and that it's fine how it is.
-Other people say if you seal it you are trapping in water and it will rot..
-And then other people say you should seal it to make it last longer.

[sethsethseth]

#9 Post by Parasympathetic » Sat Mar 19, 2011 7:42 am

[jarlethaanthonyt]

#5 Post by MissUnderstood » Fri Mar 18, 2011 5:47 pm

[bitplane]

For reference I live in Arizona and the boat is trailered, seldom being in the water for more than 6 hours at a time. Humidity and rain are seldom and issues. I am planning to do the install this weekend, so what do I do?

[shaeehickman86]

There is no debate. Would you put a plywood roof on your house without protecting it? The Arizona sun will eat a sheet of unprotected plywood in a YEAR.

[jgarzik]

Sorry, but anyone that says NOT to protect it is smoking crack.

[Nevezen]

Can you router plywood edges?

[books_kabuki]

One method is to cover the edges of the wood with strips of thin wood tape, similar to veneer. The tape is usually self-adhesive and is applied by pressing it in place with a laundry iron. Another method of finishing exposed plywood edges is to cover them with shelf edge, a type of thin, narrow molding.

[ninaheadley]

Since marine plywood is typically used underwater, you'll need to treat every surface of the wood with sealant. We prefer clear, penetrating epoxy because it works its way deep into the wood, dries transparent, and requires less maintenance than other types of sealant.

[boombox]

Accordingly, how do you finish the exposed plywood edge?

[Timothy]

A router will work fine on the edges of either ApplyPly or baltic birch. The glue in the plywood may dull the router bit slightly more quickly than solid wood but if you are only doing one desktop this is not really a factor. From an aesthetic standpoint, you will be able to see the veneer layers on the edges.

[davidpbrown]