Cheap Chinese Okume Plywood

[daveracerdsh]

I built my current DSH winter of 2010...used Okume plywood for the sponsons and chines and decks, honeycomb for the bottom and cockpit sides. The place that I get my wood at had 2 sheets of 6 mil Okume in stock.....I needed 3. I made the mistake of buying cheap knockoff 6 mil from China....what a big mistake! I used it for the sponson formers..which on my design run from the front of the inner sponson to the back of the airtraps. I noticed at Newburg that I was getting a little water in boat..this thing had never leaked a drop before. In short....I had to essentially take the sponsons and chines off to get the bad wood out....it was all delaminating. Mike Pavlik saw rig at Cullaby and mentioned that other people have had issues with this stuff. Any thoughts? Oh ya...I sealed boat with at least three coats of West System epoxy....and still this crappy wood went bad. Be Aware!

[ZUL8TR]

What ID stamp was on the cheap China knockoff ply so we know what to look for?
I always do a WBP test on a piece of the ply before use.

[Shane_B]

Dave - Ric M had some good okoume with Lloyds 1088 stamp, and if you want to drive out to Port Townsend, Edensaw carries a good selection (if you ask, they will give you a picker card to go into their warehouse and select your own sheets from what they have on hand)... they carry Euro (think Spanish and Italian) okoume and also the cheap Chinese crap - big price difference but they are up front and tell you that you get what you pay for with the Chinese stuff (voids and glue issue). I ws just out there to buy some hardwood (figured Euro Beech) for some furniture for the wife. Place is a dream for woodworkers - over 70 species of lumber on hand (major importer of exotic wood and veneer to the US).

[daveracerdsh]

I keep forgeting that Ric has Okume....I will see if I can find the stamp for the plywood. Mike Pavlick seemed to know all about it...he might be a better source of info for this stuff. I seem to remember paying around 55 bucks a sheet for good Okume and around 40 bucks a sheet for the knockoff stuff. I just hate to see somebody else go thru the same crap I am going thru...so much work to save 20 bucks 5 yeas ago.......ugh!

[DeanFHobart]

Dave,

This is what you want............

High quality Okoume marine grade plywood by Joubert. Meets BS 1088 and Lloyd's Register Type Approved.

Edensaw or Compton Lumber.

Deano............................................. ..................................................

[daveracerdsh]

Yah....I get my wood at either Compton's or Crosscut Hardwoods. I am not going to name the supplier of the cheap stuff...I have already chatted with them over this. What a huge hassle....If memory serves me correct the stamp on the Chinese crap said 1088....I could be wrong though

[boatracer69r]

Shane b, edensaw has a store in tacoma as well. If you call them a couple days before u need your plywood they will ship the wood from Port Townsend down to tacoma for free.

Dave, the good stuff is bs1088 stay away from 5655 (I think) that is the Chinese stuff. I always ask for jourbet 1088 it's from France and high quality.

[Shane_B]

True, I get my veneer from their Tacoma warehouse for furniture projects... I just like the drive out to Port Townsend and looking at all their inventory. Some day I'd love to buy that huge teak log they have there!

[ZUL8TR]

Some are illegally stamped BS 1088 and sold as that :-( , I WBP a small piece before use.

[boatracer69r]

That is very true. If it doesn't have the jourbet sticker and printing on the wood I won't take it. I learned the hard way when I had a piece of 6mil delam

[DeanFHobart]

Shane b, edensaw has a store in tacoma as well. If you call them a couple days before u need your plywood they will ship the wood from Port Townsend down to tacoma for free.

Dave, the good stuff is bs1088 stay away from 5655 (I think) that is the Chinese stuff. I always ask for jourbet 1088 it's from France and high quality.

The "Lesser" stuff is BS 6566. "BS" stands for British Standard. Google BS 1088 and BS 6566 and read all about it.

However, the BS 6566 "Should" have Marine Grade Adhesive.

[DeanFHobart]

Marine Plywood Grades

BS 1088

Although a British Standard, it is used by marine plywood manufacturers world wide. The plywood does not have to be of British Manufacture. It is an extensive document which details all characteristics of the plywood.

• The BS 1088 standard is a marine plywood specification that applies to plywood made from untreated tropical hardwood veneers that have a stated level of resistance to fungus growth.
• BS 1088 plywood must use a glue, which has been tested and shown to be highly resistant to weather, micro-organisms, cold and boiling water, steam and dry heat. There are standard BS tests for the glue.
• The Face Veneers must have a solid surface without open defects. Face veneers must be free of knots except "sound pin" knots, (no more than six in any one square foot,) the average of pin knots cannot exceed 2 per square foot over the whole surface of the plywood sheet. The grain in the veneers should be reasonably regular. Edge joints are limited, and end joints are not permitted.
• Core veneers requirements are similar to face veneers except that slits are allowed as long as they are small. Pin knots and edge joints are also allowed. As in face veneer, end joints are forbidden.
• Manufacturing Defects are strictly controlled. Poor bonds, overlaps and pleats, and gaps in faces are not allowed. Gaps may be filled using veneer inserts glued with appropriate adhesive.
• The Moisture content of the plywood must fall between 6% and 14% when it leaves the factory.
• Boards will be equally sanded on both sides.
• Finished size The length or width of a standard sized sheet can not be less than the stated size nor more than 6.3 mm (0.25") larger.
• Squareness -- The lengths of the diagonals of a sheet shall not vary by more than 0.25% of the length of the diagonal.
• Thickness tolerances:
  4 mm +.02/-0.6 ; 6 mm +.04/-0.65 ; 9 mm +.06/-0.75 ; 12 mm +.09/-0.82 15 mm +.1/-0.9 ; 18 mm +.12/-0.98 ; 22 mm +.16/-1.08 ; 25 mm +1.8/-1.16
• Face Veneer thickness -- For any three-ply construction, each veneer sheet will not be any thinner than 1/8 of the total thickness of veneers assembled dry. Multi-Ply Construction-- This applies to boards thicker than 4.8 mm (3/16")
  Each face veneer shall be a minimum of 1.3 mm and not thicker than 3.8 mm. Each core veneer shall be no thicker than 4.8 mm

Lloyd of London Certification

According to their website

"Lloyd's Register Type Approval is an impartial certification service providing independent third-party Type Approval certificates attesting to a product's conformity with specific standards or specifications, and verification of an appropriate production quality system."

In other words Lloyds ensure that the standard is met. They do not continuously inspect production lines.
Many plywood are made according to the BS 1088 marine plywood standard but they have not all gone to the trouble and expense of getting certified. On the other hand some manufacturers claim to be up to this standard but are not. As usual it boils down to you get what you pay for and it pays to go to a reputable dealer.
BS 6566

This standard is very similar to the BS 1088 with somewhat reduced quality.
It is a marine plywood standard using the same glues, but has somewhat more relaxed requirements as to the quality of the veneers. The face veneers are often of slightly lower grade and thinner. There are no voids and requirements for joins are similar.
It is generally considered an excellent material if not as pretty as the higher grade. Bright finishes are not necessarily as successful as with the BS 1088. I have used both grades and have not seen any defects in either.

[ZUL8TR]

I have also used both grades in 3 and 6mm and finished bright and noticed no differences. But the 6566 did have some surface defects that required careful selection of what part of the panel to use for exposed bright work. For the sheets I had I noticed a preferred side for bright work with the 6566 compared to the 1088 that either side was useable. I WBP pieces from both the 1088 and the 6566 and neither delamed after 1 hour of the test nor on the boat after much use. The 3 veneer 6566 sheets have a noticeably thicker middle ply and thinner face veneers than a 1088 3 ply sheet.

[daveracerdsh]

Thank you Dean....very very interesting stuff. You learn something every day..

[DeanFHobart]

Thank you Dean....very very interesting stuff. You learn something every day..

"On the other hand some manufacturers claim to be up to this standard but are not."

This is the "kicker"........... Buy only the Joubert..... It is Lloyd's certified.

[daveracerdsh]

I have been building boats long enough to have know better about this stuff. When I was cutting things out in 2010 I noticed a lot of voids in wood.....But I was in a hurry to get things done and test that I did not go back to place I bought wood and question them. Stupid mistake on my part. This stuff is so awful that it started wicking in water almost from the first time I tested boat.

[Abner30]

I recently bought some 4mm chinese occume plywood , though I didn't know it was Chinese when I ordered . It's stamped BS1088 Marine ,but I guess anyone can put that on now ? I haven't boiled it ,yet , but I don't like the fact that it has very thin surface plys and a single thick core . I'm looking for fairly uniform plys . Spec'ing the surface veneer thickness "before sanding" seems odd . Maybe mine were a decent thickness before final surfacing?

[johnsonm50]

I built my current DSH winter of 2010...used Okume plywood for the sponsons and chines and decks, honeycomb for the bottom and cockpit sides. The place that I get my wood at had 2 sheets of 6 mil Okume in stock.....I needed 3. I made the mistake of buying cheap knockoff 6 mil from China....what a big mistake! I used it for the sponson formers..which on my design run from the front of the inner sponson to the back of the airtraps. I noticed at Newburg that I was getting a little water in boat..this thing had never leaked a drop before. In short....I had to essentially take the sponsons and chines off to get the bad wood out....it was all delaminating. Mike Pavlik saw rig at Cullaby and mentioned that other people have had issues with this stuff. Any thoughts? Oh ya...I sealed boat with at least three coats of West System epoxy....and still this crappy wood went bad. Be Aware!

By fully sealing it should have prevented even interior glue from failing at least for some time. Then if it did start to fail it would only be where water managed to find its way in. Sounds like its was predisposed to fail no matter what.

[johnsonm50]

Okume by itself is rated as perishable, add that with cheep glue & its no good. Encasing it in west does work as long as it's maintained. Okume has the most desirable strength to weight ratio so despite the perishable rate is good for race boats. Sapele on the other hand is heavier & stronger & prettier & it's rated as moderately durable. I left some Shelmarine sapele scraps out in the dirt for years to see & it holds up very well. If you could build a boat with it & stay within weight I'd think it a better choice.