Confused about plywood.

[joewithaboat]

Re: Confused about plywood.

I guess the term "marine grade" can be interpreted in so many ways like "tastes great less filling!" Lots of good info in this thread!!

You know i would feel bad if a guy spent the weekend re decking and carpeting his pontoon with normal "Marine" grade plywood and then had it rot out two years later because he listened to some knucklehead here that insisted "marine" plywood is "pressure treated" when clearly most is not.
It is only interpreted that way by folks who refuse to read a little. Then regurgitated by folks who don't know any better but to listen and repeat.

 

[cyclops2]

Re: Confused about plywood.

Marine plywood ....true old standards....Is just a good grade of water resistant glue, all plies are the same specie of wood, HOPEFULLY no imperfections anywhere. Other than splicing of a ply piece to another. There is no BS 1088 any more. Just producers hyping their product & putting BS 1088 on the sheets. Knockoffs rule the marine plywood market.

Boulters was 1 of the finest marine suppliers in the USA years ago. Go to their site & read up.
Last time I spoke with them they were being priced to death by knockoffs with BS 1088 all over the sheets.

 

[joewithaboat]

Re: Confused about plywood.

Marine plywood ....true old standards....Is just a good grade of water resistant glue, all plies are the same specie of wood, HOPEFULLY no imperfections anywhere. Other than splicing of a ply piece to another. There is no BS 1088 any more. Just producers hyping their product & putting BS 1088 on the sheets. Knockoffs rule the marine plywood market.

Boulters was 1 of the finest marine suppliers in the USA years ago. Go to their site & read up.
Last time I spoke with them they were being priced to death by knockoffs with BS 1088 all over the sheets.

Interesting cyclops... looks like i was incorrect in my # 7 post. Someone does in fact lay up marine grade in tropical species. Apologies to cribber and wiki.
I have worked quite a bit with Burmese teak, I wonder are they using epoxy to lay it up? Nothing else seems to stick well to teak.

 

[cribber]

Re: Confused about plywood.

Kinda just like my pressure treated 2x8 bunks rotted out in three years from new... live and learn. I rebuilt them with cypress last year so I'lll let y'all know how that turns out in a few years. It all a matter of you get what you pay for... just make sure you get the best bang for your buck when you do!!

 

[cyclops2]

Re: Confused about plywood.

Joe
I only help other people with their repair projects at the river shed. I am " over the hill " so I do not keep up like I use to. But Epoxy might be bad news if the sheets are wacked or struck hard. Forcing a sheet to fit with a mallet. Rough docking. Lifting sling or truck forks in a wrong place.
Older glues & the wood would flex & return to ALMOST the same strength.
Some synthetic glues are very brittle after a year.

 

[joewithaboat]

Re: Confused about plywood.

Kinda just like my pressure treated 2x8 bunks rotted out in three years from new... live and learn. I rebuilt them with cypress last year so I'lll let y'all know how that turns out in a few years. It all a matter of you get what you pay for... just make sure you get the best bang for your buck when you do!!

Yea the EPA has really taken the bite out of pressure treated. It won't last like it used to in most cases.

http://www.awpa.com/standards/U1excerpt.pdf

I didn't read much of this, my trade magazines have covered the changes over the years.

 

[joewithaboat]

Re: Confused about plywood.

Joe
I only help other people with their repair projects at the river shed. I am " over the hill " so I do not keep up like I use to. But Epoxy might be bad news if the sheets are wacked or struck hard. Forcing a sheet to fit with a mallet. Rough docking. Lifting sling or truck forks in a wrong place.
Older glues & the wood would flex & return to ALMOST the same strength.
Some synthetic glues are very brittle after a year.

I see your point. The research i did on teak the first time we used it lead me to do some testing on glue joints.
System 3 Epoxy, resorcinol, polyurethane glue, 2 part urea, 2 different PVA's. The PVA's didn't do well. All others performed Ok with epoxy winning the contest.

 

[cyclops2]

Re: Confused about plywood.

When we repair a highly coumpounded curved piece of plywood We make the plywood in place. Layer by layer. Using Epoxy. The result is really beautifully curved & ALMOST like fibreglass build up from a mold.
Our first 3 attempts were so bad we sat down and ate beer as a snack.

Thankfully, we have only needed to replace 1 sheet at a time. We buy the veneers from Certainly Wood in NY.

 

[joewithaboat]

Re: Confused about plywood.

When we repair a highly coumpounded curved piece of plywood We make the plywood in place. Layer by layer. Using Epoxy. The result is really beautifully curved & ALMOST like fibreglass build up from a mold.
Our first 3 attempts were so bad we sat down and ate beer as a snack.

Thankfully, we have only needed to replace 1 sheet at a time. We buy the veneers from Certainly Wood in NY.

That's my kind of snack !

I to have used material from Certainly Wood, good supplier. The friend that turned me on to them used them for years. I now have a large re-saw so we don't by as much from them these days.

 

[jeeperman]

Re: Confused about plywood.

I'm aware of different grading of CCA and fasteners you can and can not use with them...
And...
That's all fine well and good, but just because your local lumber supplier uses improper terminology doesn't mean you can change lumber grading rules. Just because they carry "pressure treated marine plywood" doesn't mean "marine" grade plywood everywhere is "pressure treated" and ever ones "pressure treated" is "marine grade" I would bet that the vast majority of marine plywood sold is not ever pressure treated. Additionally the vast majority of treated plywood is not marine.

"Marine" and "Pressure treated" are 2 different things. You can have both but most times one is without the other.

Yes, you are technically correct and I agree.
But ya know what............there comes a time when a person should be warned that not everyone in the world sticks with the proper terminology 100% of the time.
And that is the warning I tried to provide.

So in the future others will not assume that when they ask for marine grade plywood they will only get one particular type of plywood.

Now lets argue about calling all facial tissue kleenex.

Or maybe how the color you see is not the color it is.