Birch plywood?

[davidrparker]

My favorite local lumber yard has some really nice looking NW Birch marine plywood (imported from somewhere in Scandinavia) at a reasonable price for 5' by5' sheets ($31). Any one have any experience with this type of plywood? Weight, durability, ease of working, etc. ?

[Jim Ledger]

It's not marine ply. It's a high quality product used for patternmaking because of its good dimensional stability. It has a large number of plies, the face and interior plies being the same thickness. I wouldn't know about the waterproof qualities of the glue but the decay resistance is probably not very good.

[Eric D]

Jim said it all, nothing more to add, just to echo the above, I would not use it on a boat personally.

[Chan]

Why do you say it's marine plywood? Normally birch ply is for cabinet making. Never heard of it as Marine, birch is not very rot resistant and the inner plys are generally poplar which is even less rot resistant.

[Aed]

Birch Marine Plywood is being marketed to the consumer. http://www.publiclumber.com/twinbirmar.html

Of course, the people who tried to sell this to me did stress that I should fully encapsulate it via the West expoxy methodology.

[davidrparker]

Why do you say it's marine plywood? Normally birch ply is for cabinet making. Never heard of it as Marine, birch is not very rot resistant and the inner plys are generally poplar which is even less rot resistant.
I was told by the guy behind the counter that his paperwork, from the importer, on the ply, lists it as marine plywood, 4 ply 3/16". Thanks for the input all. I'll pass on this stuff.

[Ron Paro]

Perhaps the birch ply has waterproof glue, such as used in marine and exterior plywood. This alone, does not make it suitable for boat construction. As others have indicated, the thickness and type of wood used for the inner plys is important. Also, there should be no voids in the plys of whatever is used to build a boat.

Plywood milled from okoume, sapele, and meranti are what is often used in hull construction now. Look for the BS1080 stamp.

[Chan]

3/16 4 ply plywood is junk
Anything less than 5 ply plywood has no strength at all, whether for boats or construction.

[Cuyahoga Chuck]

Plywood must always, always, always have an odd number of plys and the alternate plys must be at 90° to each other. If this rule is violated the stabilty of the plywood will be zilch. Or worse!

[ahp]

Birch makes very good furnature and wood toys. Don't get it wet. I cannot think of any wood that rots faster.

[ssor]

1/4 inch birch plywood will make wonderful bottoms in your kitchen drawers. 1/2 inch birch makes nice drawer boxes. I can't think of any other good use for it. Airplanes?

[P.I. Stazzer-Newt]

It's not super light, it's not really durable - but its really nice stuff to work - glues well, planes easily, doesnt splinter too badly - takes just about any finish....

I've known folk build stich-n-glue canoes from it - hangs upside down in the garage forty-some weeks of the year hauled out to play once in a while - not altogether a bad choice.

Orange makes speaker cabs from inch thick birch ply
http://www.musiccentraluk.com/acatalog/4x12cablarge.jpg
heavy.

[Mike Keers]

All of the above, keep it away from boats.

When I was first introduced to Baltic Birch plywood about 20 years ago, it came from Finland IIRC and was superb stuff. It was indeed waterproof, whether by accident or design; the stuff lasted for years out in the scrap pile and passed any tests I performed. I used it in boats, planes and outside projects as did others I know. The plane boys called it Airplane Birch.

Sometime maybe ten years ago I made a small outdoor sign and scroll-sawed the letters from BB, they delaminated within a week, even painted. I brought this up with my lumber supplier, and he said the Finnish plants had been bought up by Russians, and they had lowered the quality, at least the glue. Since then, the stuff is still fine for drawer boxes and similar indoor stuff, but useless outside.

I did make a self-steering windvane and used the suspect 1/4" for the wind blade, but well-coated with epoxy and paint it survived a few years of use before I sold the boat, don't know what happened to it.

[mike hanyi]

well being in finland and personally visiting the koskisen plywood factory I will vouch that they are not russian owned, they are boilproof to British standard which is much higher then any american standard.

there is several types of birchply, with different coatings that do make it waterproof, normally brown, this is used in intiors of cargo vans, and even the bed of utility trailers. mine is 17 years and ready soon for replacement.

as for boat use it is good stuff for structural stuff,like bulkheads, far stronger then anything else out there,

yes it is birch which does rot but if it is coated with epoxy or factory supplied coatings it is just fine.

learn yourself
a good read

http://w3.upm-kymmene.com/sch/internet/schintern3.nsf/bbb3150f44d4e6eec225693d0038402e/ac563ab53e04b350c2256b3a002da4ff/$FILE/Schauman_Wisa_ENGLANTI.pdf

[Glider]

In Russia, birch plywood is sold everywhere. Some people use it in the boatbuilding, but even they agree that it rots *very* fast (OK, faster than other plywood). And they use it only because they cannot find (or afford) a better ply. Maybe a proper coating might help. BTW, consider its density if weight is important.

[ssor]

IF you can keep wood dry it doesn't rot. If it gets wet and can't dry most will rot, even western red cedar as witnessed by the ends of some porch planks that were under the overlap of the siding on the north side of a house.

[few3]

When it comes to using "Baltic", "Finnish" Birch for boatbuilding, You will only get 50 years before the first 2-3 inches in the bilge start to rot. If you encapsulate them, you might get 60+ years before the bilge juice starts the decay. If you are going to use real Baltic (aka. Finnish) Birch, and only paint the panels, you should only expect 50-60 years before you will have to address the rot in the bilge.

[Jim Ledger]

When it comes to using "Baltic", "Finnish" Birch for boatbuilding, You will only get 50 years before the first 2-3 inches in the bilge start to rot. If you encapsulate them, you might get 60+ years before the bilge juice starts the decay. If you are going to use real Baltic (aka. Finnish) Birch, and only paint the panels, you should only expect 50-60 years before you will have to address the rot in the bilge.

I saw your picture, Few, and you only look about 30. Did your grandad build a boat from Baltic Birch?

[few3]

No sir, I've been rebuilding a 1958 Amphi-Ette (Mount Desert design). Built in Helsinki at Vator (http://www.vator.com/sivut/etusivu_lat.asp). Mahogany Strip chine down, Baltic Birch everywhere else.

http://img403.imageshack.us/img403/8643/balticbirchlf1.jpg

(topside interior) Baltic Birch plywood, mahogany stringers

http://img341.imageshack.us/img341/8080/balticbirchla2.jpg


I will take some pics later of some Baltic Birch skids (runners) I made for moving a generator. Thay have been sitting on crushed stone in direct sunlight, uncovered, since 2002.

[Jim Ledger]

Well, I learn something every day.

That's it for today, though.:D

[Lewisboats]

The stuff I have been buying from Menards states directly on it...no voids, waterproof exterior glue, all plies made from baltic birch. I'll take my chances at $24/sheet over $80/sheet unseen marine plywood...PLUS shipping to corn country. I mostly build small boats, and usually to test a design or for a quicky "get on the water" experience. I used $6.89 / sheet 3 ply (2 paper thin exterior and one fat interior) luan for my ScoutCanu...and it is still going strong after 4 years of sitting outside, uncovered. I just took it sailing this weekend up at Spirit Lake...and I was more worried about the mast snapping than any problems with the boat.