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Old 04-07-2011, 12:21   #1
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Phillipine Red 'Meranti" Plywood - Trustworthy?

Ahoy threadmates,

I am wondering about the worthiness of Marine grade, BS (British Standard) 1088 Red Meranti Plywood, which I might be purchasing for a boat building project. This material is apparently sourced from Malaysia, Indonesia and the Philippines and it is supposedly considered to be high quality.

My concern is that in these tropical climes, marine plywood has been known to be infested with a beetle species that bores into the softwood trees from which the plywood is sources. The beetle eggs and larvae lie dormant in the wood and apparently survive the manufacturing stage.

Also, the avoid detection in the building stage because, often, they are still burrowing through the wood, chomping as they go along, before they are ready to emerge through tiny holes that they can bore through not only wood, but fibre glass and epoxy.

Anyone know if this red 'Meranti' plywood is known for such infestations or immune to them?

Lastly, I assume that "British Standard" infers that the wood is measured in "feet" (not meters) and cut into 4x8' panels.

Any and all comments appreciated,

Best regards,

G2L
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Old 04-07-2011, 13:08   #2
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Re: Phillipine Red 'Meranti" Plywood - Trustworthy?

I've never heard of wood-boring insects (beetles) in plywood. Of course, I'm not a woodworker.
Notwithstanding:
Moisture control is key to managing a wood beetle infestation, as high moisture speeds up the development of the larvae. One inexpensive method of wood beetle extermination is to wrap the infected item in plastic and then freeze it for a week. Wood beetles cannot withstand frozen environments. Insecticides are available to purchase in department or hardware stores but may not be as effective as those applied by a certified professional, which contain sodium borate.
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Old 04-07-2011, 13:37   #3
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Re: Phillipine Red 'Meranti" Plywood - Trustworthy?

Luan (sp) mahogany is the wood typically found in plywood sourced from the Phillipines. It is not mahogany, is not really a hardwood, and is not rot resistant. Is this Meranti just another name for Luan to confuse buyers?? The original CT 41's used Luan extensively in the decks and cabins and suffered horribly from rot problems because they lived up to their 'Leaky Teaky' reputation.

I don't think there is a problem with the wood beetle surviving in plywood. The manufacturing process for plywood is pretty invasive. Don't see how any animal or it's eggs could survive the soaking, chemicals, and slicing that is involved in making plywood. In the end, believe the plywood is kiln dried which should kill just about everything.

Recently bought a sheet of Luan Marine Plywood and am not impressed. The wood seems to be softer than fir plywood and hard to fill the little grain pukas if you are going to paint it. Varnished, it fades out to a not very attractive light brown color, not the deep reddish tones of African mahogany.
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Old 05-07-2011, 04:38   #4
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Re: Phillipine Red 'Meranti" Plywood - Trustworthy?

Quote:
Originally Posted by roverhi View Post
Luan (sp) mahogany is the wood typically found in plywood sourced from the Phillipines. It is not mahogany, is not really a hardwood, and is not rot resistant. Is this Meranti just another name for Luan to confuse buyers?? The original CT 41's used Luan extensively in the decks and cabins and suffered horribly from rot problems because they lived up to their 'Leaky Teaky' reputation.

I don't think there is a problem with the wood beetle surviving in plywood. The manufacturing process for plywood is pretty invasive. Don't see how any animal or it's eggs could survive the soaking, chemicals, and slicing that is involved in making plywood. In the end, believe the plywood is kiln dried which should kill just about everything.

Recently bought a sheet of Luan Marine Plywood and am not impressed. The wood seems to be softer than fir plywood and hard to fill the little grain pukas if you are going to paint it. Varnished, it fades out to a not very attractive light brown color, not the deep reddish tones of African mahogany.
African meranti is good, but I have heard Luan described as a low quality 'cousin'.
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Old 05-07-2011, 05:31   #5
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Re: Phillipine Red 'Meranti" Plywood - Trustworthy?

Quote:
Originally Posted by roverhi View Post
Luan (sp) mahogany is the wood typically found in plywood sourced from the Phillipines. It is not mahogany, is not really a hardwood, and is not rot resistant. Is this Meranti just another name for Luan ...
Meranti plywood, commonly known as Lauan or Philippine Mahogany (Shorea family of trees - Red Lauan made from Shorea negrosensis), is a medium density plywood, generally vailable with poplar core or combination core (poplar and tropical hardwood veneers). Itís mostly used for interior parts.
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Old 05-07-2011, 06:25   #6
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Re: Phillipine Red 'Meranti" Plywood - Trustworthy?

It would be worth your while to do some thorough spec searches on plywoods.
There are catagories of specs which factor into grading.
BS 1088, e.g, dealt not only with the quality of the surface veneers (one piece or multiple splices), different grade of quality on the A and B face (yes, they are different), quality and chemistry of the (boilproof) glue, number and quality of the internal veneers, butting up (no spaces) of these veneers.

Weight per sq ft is a reasonable guage, generally heavier is better.
Thames and Brunzeel ply back in the 60s and 70s was good stuff ( Cornelious Brunzeel's 73ft Stormvogel was built of his ply) and was available up to 24 ft in length. My first skipjack used 24ft sheets of "mahogany" ply.
As Roverhi said, the wood is varied, could be meranti, sapele, okoume, luan, or a number of the Pacific or Honduras woods.
I have never seen, and I have sold acres of the plys, a beetle , but there is a tiny worm, about 3mm long a 1 mm in girth which shows up in bundles of ply manufactered at the same time.
Not unusual if you consider the trees which are turned on a lathe type cutter, to peel the veneers.
There are different schools of thought on glassing "mahogany" plys for longevity, based on your weather conditions at time of building. Here in Bermuda, with an average annual humidity of 80% it rots at what seems a short time, 2-3 yrs.
Woodenboat did a comprehensive and thorough article a few years back on this subject, worth anyone's to source it out.
Hope this helps.
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Old 05-07-2011, 06:31   #7
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Re: Phillipine Red 'Meranti" Plywood - Trustworthy?

I have used hundreds of sheets of BS1088 meranti plywood over nearly 40yrs of boatbuilding and have never seen any kind of infestation, in fact i have found consistently good quality regardless of the manufacturer or country of origin. If you find inner plies of any other species it is not BS1088. While not a pretty plywood you are not likely to find a better structural plywood for the money. Many people use Okume if weight is an issue but meranti is stronger, more rot resistance and significantly cheaper.
Steve.
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Old 05-07-2011, 07:59   #8
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Thanks to All - Re: Phillipine Red 'Meranti" Plywood - Trustworthy?

Thanks guys.

Some innvaluable comments on the thread above.

Beetle infestations certainly do occur in plywood here in the tropics, and I have supplied a reference which will testify to this fact.

The plywood in question probably comes from the PI, and I have heard of the borate and other remedies, though they are rarely-if-ever practical or practiced in this part of the world.

From what I am getting above, it seems that any infestations usually cannot survive the manufacturing process, and, if present, most likely occurred, after the fact, due to the wood having been improperly stored and thus having becoming overly moist - the only environment in which the beetles might become interested.

However, Bluestocking seems to have seen the larvae emerging after the manufacturing process, which is duly disturbing. See my final post below on the "little white worms".

Also, if interested, please check the relevant horror story by doing a Google search on the yacht "Razzle Dazzle", and thank all for your input.

Best regards,

G2L
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Old 05-07-2011, 08:20   #9
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PS - On Little White Worms v. Beetles ...

... Unfortunately, it's the "little white worms" that cause the problems.

The adult beetles lay their eggs on or just under the surface of the wood. The eggs hatch and the larvae feed on the wood, borrowing deep inside, apparently to avoid predation and to "get at the meat" of things : )

When the larvae are about to mature, they bore through the outside of the wood, and even through epoxy if the wood was not properly coated in three or more layers. Then, the emerge as tiny worms, soon sprout wings, and fly away to repeat the cycle.

It seems that most of you guys have not encountered the beetles because you live significantly north of the equator, where there are none.

Just some added info,

G2L
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Old 05-07-2011, 08:52   #10
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Re: Phillipine Red 'Meranti" Plywood - Trustworthy?

Truth be told, here in my area, U.S west coast marine grade A-C quality fir stands up much better in the boating building usage, and glasses over better.
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Old 05-07-2011, 12:34   #11
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Re: Phillipine Red 'Meranti" Plywood - Trustworthy?

Thanks Blue Stocking,

As always, appreciate your comments.

G2L
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