Marine Plywood - What is the difference between types?
Mak37
my plywood optionsI was prepared to order some Okoume that meets "BS 1088
Marine Standards" then I found a supplier offering "Brazillian BS 1088
Mahogany" which is approximately 60% the cost of the Okoume. All sizes (except
the 1/4") offer the same number of plys per sheet. What's the difference
between these two products? Does antone have experience with the Brazillian
product?
Which product should I use? Or should I do as some have suggested and aviod
the more expensive B.S. (1008) marine ply in favor of exterior plywood?
wr...@my-dejanews.com
time economically which may explain the sizable discount. Do not go to
exterior plywood, unless you are making this boat for a hated mother-in-law.
Even that might be a bad idea since she may survive. -g-
Even A-A exterior ply will have voids in the inner layers. Why don't you call
a good plywood manufacturer and talk to one of their techs? They are usually
very helpfull.
Regards, Dan
-----------== Posted via Deja News, The Discussion Network ==----------
http://www.dejanews.com/ Search, Read, Discuss, or Start Your Own
Classic Boatworks of Maine
that meets the current standards would be appropriate for your stitch and
glue project.
--
Good Luck and Fair Seas
Marshall and Jo Duhaime,Jr.
Classic Boatworks of Maine - We build and restore classic wood boats.
http://www.nemaine.com/classicboatworks
John McCoy
>I'm looking to built a boat (stitch and glue) using marine plywood. Looking at
>my plywood optionsI was prepared to order some Okoume that meets "BS 1088
>Marine Standards" then I found a supplier offering "Brazillian BS 1088
>Mahogany" which is approximately 60% the cost of the Okoume. All sizes (except
>the 1/4") offer the same number of plys per sheet. What's the difference
>between these two products? Does antone have experience with the Brazillian
>product?
BS1088 is a standard testing procedure to garauntee the strength and quality
of plywood. As far as I know, it can be applied to plywood made from any
species of wood, altho you only seem to see it for the various "mahoganies".
There is another British Standard (BS) for plywood for aircraft use, who's
number escapes me right now - it is a more stringent spec, which includes
boiling the plywood to make sure the glue doesn't weaken.
I beleive you can consider any BS1088 plywood to be effectively equivalent.
John
(wondering which "mahogany" grows in Brazil)
crashcity
the species of wood?
John McCoy wrote:
> jo...@casema.net wrote:
>
> >i'll be the dumb one and ask just what does the BS1088 standard tell
> >me. what at the test parameters.
>
> Actually, I'd like to see that in detail too. Other than knowing it specifies
> the size of defects allowed in the inner plys (small), the number and
> manner of joining veneers to make the plys, and the characteristics
> of the glue, I don't know the details of the standard.
>
> > i'm not a boat builder and have some
> >repairs to make soon to my tri. i was thinking of getting the
> >expensive stuff from bruynzeel but if a cheaper one meets the same
> >standards...?
>
> I think it's safe to assume Bruynzeel exceeds rather than meets
> the standards. For something highly stressed, like a racing
> tri, you might want to exceed the standards. For a 12' dingy,
> you probably don't need the extra.
>
> John
jo...@casema.net
beat a keyboard into submission upon which it cried out...
>ma...@aol.com (Mak37) wrote:
>>I'm looking to built a boat (stitch and glue) using marine plywood. Looking at
>>my plywood optionsI was prepared to order some Okoume that meets "BS 1088
>>Marine Standards"
>BS1088 is a standard testing procedure to garauntee the strength and quality
>of plywood. As far as I know, it can be applied to plywood made from any
>species of wood, altho you only seem to see it for the various "mahoganies".
>I beleive you can consider any BS1088 plywood to be effectively equivalent.
okay guys,
i'll be the dumb one and ask just what does the BS1088 standard tell
me. what at the test parameters. i'm not a boat builder and have some
repairs to make soon to my tri. i was thinking of getting the
expensive stuff from bruynzeel but if a cheaper one meets the same
standards...?
john
John McCoy
>i'll be the dumb one and ask just what does the BS1088 standard tell
>me. what at the test parameters.
Actually, I'd like to see that in detail too. Other than knowing it specifies
the size of defects allowed in the inner plys (small), the number and
manner of joining veneers to make the plys, and the characteristics
of the glue, I don't know the details of the standard.
> i'm not a boat builder and have some
>repairs to make soon to my tri. i was thinking of getting the
>expensive stuff from bruynzeel but if a cheaper one meets the same
>standards...?
I think it's safe to assume Bruynzeel exceeds rather than meets
PC
plywood is "glued" with the same film-glue, as exteriour ply.
------ They don't use any liquid glue, for any plywood, but a film,
that work when it's heated, while the layers are pressed.
This also mean, that a lot of interiour plywood are much better than
one shuld expect, for outdoor use.
You can find "Brazilian" ply that cost much less than the tested ply's.
And as the glue are the same, and the tests deal with boyling a
sample for a period of time, the choice shuld be easy.
I know of two 2 meter prams build from the cheapest "Brazilian" ply
some 6 years ago, one been in the water since, and no de-lamination
on that one, Treaded with penetrating Epoxy though.
So it's not the glue to worry about, only what kind of wood, and the
strength.
Our new Longboat design have been updated.
You can go to
http://w1.1396.telia.com/~u139600113/index.htm
or strait to ;
http://w1.1396.telia.com/~u139600113/mold.htm
Best regards
Per Corell
Cyber-Boat
Copenhagen -- Denmark
jo...@casema.net wrote in message <76jpkg$g2r$1...@news.casema.net>...
>on Fri, 01 Jan 1999 01:49:35 GMT, igo...@ix.netcom.com (John McCoy)
>beat a keyboard into submission upon which it cried out...
>
>>ma...@aol.com (Mak37) wrote:
>
>>>I'm looking to built a boat (stitch and glue) using marine plywood. Looking at
>>>my plywood optionsI was prepared to order some Okoume that meets "BS 1088
>>>Marine Standards"
>
>>BS1088 is a standard testing procedure to garauntee the strength and quality
>>of plywood. As far as I know, it can be applied to plywood made from any
>>species of wood, altho you only seem to see it for the various "mahoganies".
>
>>I beleive you can consider any BS1088 plywood to be effectively equivalent.
>
>okay guys,
>
>i'll be the dumb one and ask just what does the BS1088 standard tell
>me. what at the test parameters. i'm not a boat builder and have some
>repairs to make soon to my tri. i was thinking of getting the
>expensive stuff from bruynzeel but if a cheaper one meets the same
>standards...?
>
>john
>
>
John McCoy
>I'm wondering what makes a plywood "marine grade" to begin with. Is it the glue?
>the species of wood?
A marine plywood should have three things, as far as I know:
1) waterproof glue (this one is pretty obvious).
2) no voids or breaks in the inner or outer plys (a requirement for strength and rot resistance).
3) many thin plys (for strength).
Regretably, the US plywood industry appears to base "marine" grade on items
1 and 3 only, and ignores number 2; thus most US made "marine" plywood is
unsuitable for boat construction. BS1088 rated plywood will meet all 3 criteria.
John
Mike Finch
>
>on Fri, 01 Jan 1999 01:49:35 GMT, igo...@ix.netcom.com (John McCoy)
>beat a keyboard into submission upon which it cried out...
>
>>ma...@aol.com (Mak37) wrote:
>
>>>I'm looking to built a boat (stitch and glue) using marine plywood. Looking at
>>>my plywood optionsI was prepared to order some Okoume that meets "BS 1088
>>>Marine Standards"
>
>>BS1088 is a standard testing procedure to garauntee the strength and quality
>>of plywood. As far as I know, it can be applied to plywood made from any
>>species of wood, altho you only seem to see it for the various "mahoganies".
>
>>I beleive you can consider any BS1088 plywood to be effectively equivalent.
>
>okay guys,
>
>i'll be the dumb one and ask just what does the BS1088 standard tell
>me. what at the test parameters. i'm not a boat builder and have some
>repairs to make soon to my tri. i was thinking of getting the
>expensive stuff from bruynzeel but if a cheaper one meets the same
>standards...?
>
>john
>
public library (it's too expensive to buy at £50 - about $85). The essential
features seem to me to be:-
Only the heartwood of "moderately-durable" or better tropical hardwoods can
be employed (a special exemption is made for Gaboon because of its usefull
low weight);
Only "weather and boil-proof" (WBP) glues can be used;
Surface veneers must be free of open defects and gaps and have no end-to-end
joints. Edge-to edge joints are permitted but must be at 1 foot or greater
intervals;
Core veneers - 1 gap at most in any board edge, no bigger than 0.5 mm;
There are also detailed rules for the number and thickness of veneers, and
size tolerances.
A procedure to test the glue/veneer join is specified for the supplier or
customer to use. A ply sample is boiled for 3 days, and then a knife is used
to pry apart the joints to see how good they are. No wood fibres adhering to
glue gets a score of 0, complete adhesion (i.e. the wood fails rather than
the join) gets a score of 10, with in-between values depending on the amount
of wood still sticking. The pass mark is 5 or better. This tests the glue,
the smoothness of the veneer surface and the manufacturers quality control.
There is a good article about plywood by Richard Hare in the Dec 1998
edition of "Classic Boat".
My own experience is that Bruynzeel ply is superb, although not meeting
BS1088 solely because its glue is not boil-proof (but then I've never met a
boat-boiler). In particular I have used it for a centreboard and although
most of the epoxy and varnish protection on the bottom edge is gone, there
is no sign of de-lamination after 4 years. There seems to be general
agreement that it is extremely good and will last well beyond its 10 or 20
year guarantee.
I also tried testing some exterior grade ply to see how well it performed.
It was made from "Phillipine mahogany" (= Lauan = Meranti) and used WBP
glues. I epoxy coated and varnished it and left it on my garage roof (here
in the south of England). It was just starting to show signs of
de-laminatation after 3 years. Other people report much better results with
such ply. My conclusion is to buy as good as you can get unless you are
certain of the quality of the product.
Mike Finch
Stan Borkowski
wrote:
I believe there was an article on this in Wooden Boat nov ? dec ? 1998
(Sorry I'm rather far from my library just at the moment...)
----------------------
StaH
John McCoy
<the goods on BS1088 snipped - thanks Mike>
>My own experience is that Bruynzeel ply is superb, although not meeting
>BS1088 solely because its glue is not boil-proof (but then I've never met a
>boat-boiler). In particular I have used it for a centreboard and although
>most of the epoxy and varnish protection on the bottom edge is gone, there
>is no sign of de-lamination after 4 years. There seems to be general
>agreement that it is extremely good and will last well beyond its 10 or 20
>year guarantee.
I assume the idea behind the boiling test is to simulate several years of
exposure to warm (say 30 C, a reasonable temp for the tropics) water
in a much shorter time (we do a lot of this in my business, and call it
Accelerated Life Testing. There is much disagreement about how
accurately it simulates the real world...).
John
Jacques
stitch and glue. Everything being equal, buy the one that bend easily.
Okume is usually very easy to bend.
As for exterior, ask the designer. If this is one of our designs, when we
specify marine, it is always for the mechanical properties, never for the
glue or the wood species.
--
replies to:
Boat Plans Online
http://www.bateau.com
Mak37 wrote in message <19981231094425...@ng-fa1.aol.com>...
>I'm looking to built a boat (stitch and glue) using marine plywood.
Looking at
>my plywood optionsI was prepared to order some Okoume that meets "BS 1088
>Marine Standards" then I found a supplier offering "Brazillian BS 1088
>Mahogany" which is approximately 60% the cost of the Okoume. All sizes
(except
>the 1/4") offer the same number of plys per sheet. What's the difference
>between these two products? Does antone have experience with the
Brazillian
>product?
>
John Bell
>I'm looking to built a boat (stitch and glue) using marine plywood. Looking at
>my plywood optionsI was prepared to order some Okoume that meets "BS 1088
>Marine Standards" then I found a supplier offering "Brazillian BS 1088
>Mahogany" which is approximately 60% the cost of the Okoume.
Where? Do tell!
JB