marine plywoods from china revisited

Could you insert the pic as an attachment, in original size? We can't see the details from that one...

 

I was talking to Edensaw Woods of Port Townsend during the wooden boat festival. Give them a call

They sell "real" okume as well as the cheap Chinese stuff. They said the Greek plywood was good. The Israelis no longer make gaboon ply. I have heard various reports about the Chinese plywood.

If you need to save money I suggest
1) build a smaller boat
2) Do NOT save money on the hulls. They are what keep you alive when at sea and you can never change them. But you can, for example, start with no electronics, buy used sails etc.

I may be wrong but I believe the BS1088 has been superceded? And certainly one of the best boatbuilding plywoods is/was Brynzeel ply from Holland. But that didn't comply with BS1088

Richard Woods of Woods Designs

www.sailingcatamarans.com

 

Sorry, Daiquiri. I just used the "IMG" tag and referenced the same picture I had up elsewhere in this forum. Less wasted server space.

You can see it as an attachment in different resolutions here, in the original post:

http://www.boatdesign.net/forums/materials/teak-holly-plywood-37514-2.html#post457804

 

China does

exactly what the customer wants. CHEAP>>CHEAP>>GREEDY American bussinesses.

PERIOD !!!!


Or the Americans are to damm lazy to dump the lowest priced guy they picked......Usually true.

 

i am considering bulkheads in foam glass too !

 

I decided to go with foam/glass not only because it will last longer, but because it's much easier to build in the case of my catamaran.

The wooden beam type bulkheads (that connect the two hulls together) called for that plywood in the picture and complicated caps and trusses laminated from thin slivers of sitka spruce. It would have taken me eons to make all of that stuff compared to just cutting out some foam, plopping it down on a good surface and infusing both sides at once.

No contest on speed of fabrication.

 

Richard Woods is very much on target about BS 1088. I recall years ago a very good Marine supplier stating the BS 1088 was defunct. But still used to generate higher profits from the BS 1088 lovers.

 

I had not heard that BS1088 had been superceded, why and by what? Why did Brunzeel not comply,hard to imagine but i vaguely recall hearing that too. What i like about BS1088 is that as i said i have used many hundreds of sheets of ply from all over the world and it has been of consistent quality, i have used Brunzeel years ago and to be honest didnt find it any better or worse than an equivilent panel from Israel, or France or Indonesia or, so it gives you some confidence when buying from afar.
Steve.

 

Copy of my info on Aussie grade materials, explains some questions being asked here.

Information on Plywood
Marine Plywood manufactured to AS/NZS 2272 Plywood - Marine is a purpose built structural plywood intended for use in hulls of boats and other marine applications and also in aircraft construction. It has a permanent Type A phenolic bond and is manufactured from selected species based on density, bending strength, impact resistance and surface finishing characteristics.
None of the marine species are naturally durable and preservative treatment will be required in marine plywood used in some marine environments.
Preservative treatment of marine plywood can be either carried out in a treatment plant prior to sale or in situ. In either situation the protection is an envelope treatment and all cut edges should be re treated in situ.
As most preservatives affect resorcinol bonding, advice should be sought from adhesive and preservative manufacturers if gluing of preservative treated plywood is intended.
Marine plywood to AS/NZS 2272 is made from selected species and therefore has known and consistent structural properties. The assigned stress grade of plywood manufactured to AS/NZS 2272 is F14.
Marine plywood to AS/NZS 2272 has two A grade faces and a Type A bond. In the Australian/ New Zealand Standards grading system it therefore has a grading of AA - A bond
Note that marine plywood manufactured to BS1088, as imported into Australia, does not have predictable structural performance and must not be substituted for AS/NZS 2272 marine plywood. For assured performance marine plywood should be branded with the “PAA Tested” marine plywood stamp
Four types of gluebonds are defined and specified in AS 2754.1 Adhesives for Plywood Manufacture. The bond types are - A, B, C and D, in decreasing order of durability under conditions of full weather exposure.
Type A bond, is produced from a phenol formaldehyde (PF) resin, which sets permanently under controlled heat and pressure. It forms a permanent bond that will not deteriorate under wet conditions, heat or cold. It is readily recognisable by its black colour.

 

Actually, by definition, 3mm ply cannot comply with BS1088. Why?

BS1088 calls for a 1mm thickness minimum, for each ply in a sheet.

Since 3mm ply is 3mm overall thickness, you have to take some of the 1mm thickness minimum out of the faces to get the glue lines and all the wood into a 3mm sheet.

This is why Boulter sells the 3mm as BS6566, even though it is manufactured by the same Greek supplier using all the same materials as the larger BS1088 sheets.

The Lloyd's Certificate is what you want. If your plywood manufacturer is selling something with a specific Lloyd's number and can provide you with a copy of the certificate from Lloyd's, you are usually in good shape. I have a copy of the certificate for my wood to keep with the ship's papers after the build is complete.

 

Hi Yellowcat,
Kurt Hughes does not recommend using bs1088 for cylinder mould construction. He recommends BS 6566 instead. The 1088 is too stiff to conform well to the curveature of the mold.

I am currently building his daycharter 36, and built my hulls using 3 layers of 3mm 1088, bagged down on the "biaxial" mold. I had some problems with voids, particularly at the places that have the most compound curve. I had to spend some extra time and effort correcting these voids.

Using a straight mold instead of the biaxial (which is also curved in the fore and aft direction) might help with this problem, but I would consult with the designer, and try and get some independant judgements as to the flexibility of the plywood and make sure it is suitable for cylinder moulding. I also used the Greek stuff, from boulter ply, and it was excellent quality.

What happened in my case though, was that Boulter's website advertises their 3mm stock as 6566, because it is impossible for 3mm ply to have adequate ply thickness to meet 1088 standards, plus the glue, and still be only 3mm thick! So they don't advertise it as 1088, but it meets 1088 standards in all other respects, (and is stamped as 1088) When my ply arrived, I thought, Oh great! I ordered 6566...Its like an "upgrade"... good for me. the problem was though, it turned out to be a little too stiff.

 

Hi Charly,
thank you for the input, even at 6566, you find it is too stiff ! did you slot it a bit it is to be sloted on x and y , i did that for curved cabinets. It will weaken the ply when sloted in the wrong grain vs loads. Corecell is also sloted for shaping, it also allows for infusion . I got all the samples from them and read about the techniques. I am considering having a double floor because i plan to be in very shallow waters. This dates in the 60s and 70s when we built, repaired and repaired again wood sneaks and small boats.
We had very important tides, we can walk 3/4 mile all the way to the shipping lanes, important currents too, but a paradise for kiting in flat waters. The Bahamas are also in our trips portfolio.
The secondary floor can be composite, and a pvc blader can be added.
We do not intend to live inside the hulls, at 30 inches max width, it will allow only to get in for servicing. No or little loads will be on the trampoline. The stringers and bulkheads will serve as the permanent skeletton even at the vaccumed bagging.
The design criterias can be discussed in another thread.
For your information, there has been urea formaldehyde and created problems in houses.
We are asked to specify "green" ecolo melamine for cabinets, that means without formal... lukily, epoxy will cap that stuff found in the marine plys. But care has to be taken on construction site.
I see there is fire retardant stuff sold by Gurit. Ampreg 21FR etc.
I am sorry to hear you had problems with voids, it is a pain in the neck, a strong light behind the panels will show where and one can drill small holes for filling them. The fun part is that it is easy help for your friends to make themselves usefull, but always with gloves, no greasy hands !
Cheers, i appreciate !
Mike

 

This is interesting and those plys must not have voids.

 

Lloyd's Rated 3mm $31.50 World Panel Products, Inc.
www.worldpanel.com
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