Marine ply...or is it?

[shindig]

I bought a sheet of 9mm marine ply today £23 ....the guy who got it out of the warehouse didn't seem that sure what he was looking for to me....so how do i know i got marine and not some inferior product?!

It's got 5 layers - thin outer veneers, thick layer then thin middle layer...does that sound right??

[allan]

I am no expert and, hopefully someone else may help. I seem to remember reading somewhere that marine ply has no voids in the inner layers. If you check around the edges, it may give you a clue.
Allan

[Camelot]

I've only ever bought 2 sheets of Marine ply - one 9mm and one 18mm - but both were stamped 'marine'. That might be something that is unique to the supplier I used (place in splot, green building - can't remember name!), but it did leave me in no doubt.

[draycott]

all marine grade ply wood will be clearly mark with a stamp and its makers name if it has no stamp take it back just to be safe

[Deleted]

hi
Marine ply must be kite marked BS:1088 which is the standard for the waterproof glue line however there are differences in the wood line I cant remember all the standards as its a long time since I studied There are structural grades and rotary grades for the timber
The BS: 1088 kite is the most important

[shindig]

Thanks folks - there is a stamp on it which i will have a good look at for the BS 1088 marking. I'll let you know!

[Deleted]

It all depends what you are using it for ..and how you are using it? Most exterior building grade ply is fine for boats. The important thing is that waterproof glue is used. As with most things, if you want 'marine', multiply the price by 3. Unless you are actually going to permanently immerse it, just buy exterior grade from any DIY place. Longevity will be much improved by making sure all cut ends are sealed with an epoxy / polyurethane varnish or similar.

[Deleted]

I would re-iterate what Peter says, use a suitable epoxy or varnish. The high price doesn't mean it can survive purely on it's own. It will still soak up moisture & swell then go soft.

I remember when I bought an allocation a few years ago (over £200 worth) from a reputable merchants in Bristol, the specialist told me the only thing that makes it Marine grade really is the waterproof glue used between the sheets, the ply itself is not treated. So protect your investment!

Mark