BYYB Forums

Hello, I am mainly a lucker, have posted a few times, more with questions than advice and have some more questions.

Looking at starting my next boat building project and the cost of marine grade plywood (and shipping) may just end it before I begin.

Seems i remember some people posting comments about MDO and lunan plywood, in fact someone was even running some "test" on the stuff. I tried searching for old threads, but couldn't find the comments, hate to resurface old stuff, but could you guys help me out?

Oh, my newest project with be an 18' duck hunting boat. I want something like a TDB or Bankes type boat. Something with high sides for concealment and pushing off bigger waves. Couldn't find plans anywhere so working up drawings and models now.

Thanks much for the help.

Andrew

Hey Andrew

I’m building my second boat using MDO, a WEEKENDER and 14ft Power Skiff (under construction).
My only complaints are, I cannot find any ¼”, and you have to rough sand the white overlay to insure the epoxy penetration. (Not a real big deal)
If you decide to use MDO try to purchase MDO with the overlay on both sides. 3/8” may be more difficult to find.

Karl

White overlay? I hope we are talking about the same stuff. Here we have Menards (like home depot) that is selling a product they labeled as MDO, it's 3/4 plywood with a paper veneer/lining on both sides. I have looked at couple stacks and haven't seen any voids, but it does have rather thick veneer layers.

Are we talking about the same stuff?

It may be the same.
MDO (Medium Density Overlay) plywood’s primary use is for outdoor signage.
It has a thin paper like overlay material on one or both faces. The overlay material has two layers one (the finish layer) is white, and a base layer which is brown.
One of MDO’s advantages is, it makes a nice finished product.

FYI
The person who suggested I use MDO to build my Weekender is the shipwright at the Chesapeake Marine Museum.

Andrew,

About 7 years back I built a canoe with the expectation of it only lasting a couple years before it disintegrated, so I built one out of white pine boards and 1/4" lauan plywood (total cost of the project was less than $100). The outside was painted with one coat of epoxy and two coats of house paint. It is still going strong 7 years later even after being stored outside in the weather all that time. Lauan and pine certainly aren't the material of choice for a long lasting quality build, but if you want inexpensive and easily available material it is someting to consider, it all depends on how long you want it to last and how much you want to spend.

John K.

MDO is a pretty good material, made from Douglas fur or western larch, throughout the panel. These species have good rot resistance and the glue used is water proof. It comes in limited thicknesses, 3/8" being the thinnest (3 ply) up to an inch (7 ply, I think) and this is it's weak point. Because of the limited number of veneers used for it's construction, it can be much weaker then a marine counterpart. The construction quality is not as high as most marine grades also and it can be heavier then some of the marine plywood offerings. Ply gets it's strength from the veneer count (the higher the better) and good construction practices (voids, surface defects, repairs, knots, etc.).

MDO comes a few different ways, faced one or both sides and primed both sides (white). The paper face is quite well stuck to the outer veneer, but can show grain "print through" in the Douglas fur versions. It can save a lot of time in finishing up panels intended for paint, in fact this is what it was designed for.

In highly stressed hulls, I wouldn't recommend it as a planking material, but it does well as bulkheads, cockpit seats, interior furniture, lockers, etc. A heavily built plywood over frame design can sometimes use MDO as planking, but tortured ply designs need real good panels or they'll break under load (at voids and defects, or from the radical bends it's forced conform to). Most very small boats (under 18') can't really take advantage of MDO. It's heavier, has fewer veneers, more voids and defects, which can cause problems in small craft, with their typically quick bends and curves.

Lauan is a generic name given to a mahogany looking cedar, found in the south far east. It isn't mahogany, doesn't act, machine or as strong as this well loved wood, but it does have a very similar look to most folks eyes. A wood worker with much mahogany experience will notice the difference, but most people think it's mahogany.

Lauan is of questionable quality, for the most part any more (like many things). Quality controls in the production countries is very sketchy at best, so buyer beware. Typical lauan found in the local lumber store will be "cabinet grade" material. This is built of paper thin outer veneers of lauan, with who knows what kind of wood inside. The glue generally isn't water proof, voids, defects and poor construction usually make this a disposable product. I use a lot of it making templates or patterns to size up the good wood.

Embalmed in goo, lauan and MDO can have much extended life spans. Many small skiffs, canoes, kayaks, etc. have been built, some sheathed in 'glass others just painted with epoxy. If the surface coating on these craft are kept intact, good care is provided and regular maintenance performed when necessary, they can be very durable.

So pick you pain. In typical wooden boat construction, the planking material is the best wood used on the boat, for good reason, it keeps the wet off your feet. You can short cut the planking stock with a cheaper material, but realize what this means. The savings you get with a less costly plywood, may be negated because you have to use extra protection (CPES, epoxy, 'glass, etc.) and maintenance to keep it from rotting, which could easily make up the difference compared to the good stuff.

Thanks for the comments, you talked me out it. Somehow i get this picture of me being out 5 miles, in 5 foot waves and it starts to delamated.

Just wish there was some place close to get marine grade plywood. Last time I ordered it from Enden Saw, or something close, great people to work with, but, they need to make a buck, as does the train operator, as does the truck driver, etc, etc. In the end, shipping costs me as much as the wood.

Andrew

Greetings,

If the drive from Milwaukee down to the southwest suburbs of Chicago isn’t too far for you, (I’d guess about 90 minutes), then you can obtain BS 1088 Okume Marine Grade Plywood from …

Plywood & Door, 6335 W Joliet Rd, Countryside, Illinois, 60525, (708)354-2155

These guys are importers (wholesale) and normally sell only to woodworking businesses such as the local boatyards and furniture makers. However, if you tell them you are building a boat and will pick the wood up yourself, they will sell to you directly.

I bought all the plywood for my weekender (under construction) about 18 months ago and I really like it. No voids in the glue, lots of laminations, and it cuts and machines well. I think it was made in France so the sizes are metric. Instead of 1/2 inch, 3/8ths and 1/4 inch, you will be buying 12mm, 9mm and 6mm panels. The panels are just a touch wider and a few inches longer than standard USA panels, so be prepared to lug them back to Wisconsin with your tail gate down.

They need a little advance notice to make the sale happen as the office folks are in one building (a really cool geodesic dome general office space building), but the plywood is stored a mile or two south in a public warehouse, and getting the paperwork back and forth is a pain. But everybody was fantastically nice.

I caught them when their stock was low and the exchange rate was rising and they made me wait a few months until the dollar/franc rate fell back to “normal” ranges before they stocked back up on Okume. It made the difference between paying $55 a sheet and $75 a sheet. They also stock some very nice aircraft-grade birch plywood if you are thinking about maybe building an aeroplane instead of a boat.

Last I checked, they do not have a website, but if you call the phone number they can probably fax or E-mail you a product and price list.

Good luck,
Tom in Elk Grove Village, IL

Thank you Tom in Elk Grove Village.

You have no idea how much time I have spent looking for plywood, from someone "local". I just hung up with them, great people to talk with on the phone, probably won't start the project until summer, but sure won't lose their name and number.

Thanks again.

Andrew

Greetings,

Your welcome.

Hey, if you have a spare $4,500 laying around and you want to skip over the whole "where do I get my plywood from" thing, then you can purchase a ready built weekender from ...

http://www.sailingworldinc.com/cgi-bin/s...gi?id=2191

The boat has Ohio registration and was in good shape the last time I looked at her in September. She has a really nicely made custom fitted canvas cover (not in any of the pictures) that slips over the bowsprit and snaps down to the rub rail.

She is probably over priced at $4,500 dollars as similarly sized day sailers can be had for half that price in the same boat yard, or can be had for the same price with a 5 hp gas engine hanging off the transom.

But, she sure is pretty.