oriented strand board (OSB)

Good afternoon everyone,

May I ask if anyone has used oriented strand board (OSB) in their boat building project?

I ask simply because I have had some machinery arrive from Canada crated up in OSB.

I have not before seen such a particle board and have learned that the Canadians crated up my machinery in a grade of OSB equivalent to or near enough to a marine grade ply.

The OSB has such an unusual finish that I'm pondering it's use as a feature bulkhead... Well, if my lounge room can have a feature wall, why can't my boat have a feature bulkhead?

You thoughts and comments are most welcome.

James.

 

OSB is probably the lowest grade material available. Completely and totally unsuitable for boat building. I can think of no other wood less suitable, now that I'm thinking of it.

throw it away, its not even safe as fire wood.

cheers
B

 

What's most interesting Boston,

Thanks for the feedback. I'm keen to learn more about why you feel this board is not suited.

I've just now compared the data from Gaboon marine ply to the OSB that formed the crate my machinery arrived in.

Guess what... They are almost identical with one exception, the Gaboon ply is lighter.

So what have I missed?

Oh, I hasten to add that I'm not trying to cut costs or recycle materials, its just that I find the surface laminate texture of OSB rather appealing.

James.

James.

 

give it the boil test and see how it turns out

take six pieces and boil them for a half hour or so. then bake them in the oven for a while.
Repeat a few times

marine ply holds together
OSB will be splinters before it even gets out of the pot the first time.

 

I used OSB for some of the stations on my strongback for the Raptor and while it didn't hold brads as well as the particleboard stations, it worked for a one-off boat. I can see using OSB in non-structural, non-water contact applications. It will swell and lose strength if it stays wet for weeks, but the occasional soaking won't kill it. Like all wood materials, it's better to coat it with something for protection.

Finally, I'd like to say "good on you" for trying to re-use and recycle materials in your build. I'm using plywood from a packing crate for the deck and bulkheads in the kayak I'm building now.

 

OSB has several obvious issues that make it unsuitable for marine life. It can be had with WBP adhesives, but it lacks the qualities needed in dynamic loading situations, that will be seen in a boat. There was a yacht built by a guy that owned a company that makes OSB, though he used a special form (similar to OSB) and of course WBP adhesives, but the result was a whole lot heavier then more conventional build methods. He knew it, but wanted to prove the viability of the product. I know of no other success stories with OSB in marine environments. The yacht I mention is well documented (Miss OSB) and she was recently sold for over 10 million, with few expenses spared in her construction. The OSB as mentioned was a special batch and used as a very heavy core in a composite structure, were the 'glass bore the loads, not the OSB. Considering she is a 65' by 15' powerboat, the 10 million seems a wee bit excessive, even considering the lavish appointments, which includes 25 coats of exterior varnish.

James, the best thing you can do is familiarize yourself with the physical properties of both OSB and common marine plywood products. Better yet, rip a 3" wide, 8' long strip of OSB off a sheet and try to bend it around a simple curve, simulating a plank and watch what happens (stand clear). OSB also can't tolerate shock loads very well, plus has several other issues. This said, if used in an engineered structure, it will work just as well as an Okoume plywood hull, though a lot heavier and with a substantial laminate schedule to compensate for it's issues.

 

I think that it is possible to use, just like any other material. OSB lasts for years in structural use. For example, walls, roofs and floors. It has, as it name indicates, fibers oriented so the strength is different one way than the other. A major drawback is its weight. Land based buldings are not as weight sensitive as boats.

 

Certainly it's not an ideal material for marine applications, but if you have a bunch of it free, it can be used.

 

Ive worked remodeling and insurance repairs for way longer than I ever wanted to, and I've seen more failures in OSB and particle board than in all other materials combined. Its very common for the stuff to delaminate when exposed to moisture. It also has a nasty habit of swelling, a 3/4 piece can easily end up more like a full inch once its been water logged a few times. Also there is the glue issue, those companies that produce the stuff get caught all the time producing substandard material for the grade marked. There's also an ongoing issue with roof failures where the stuff is used as a sheathing material. So I'd have to really wonder if its worth the effort to use it even as a core. As Par said, there's "one" boat out there and its material was custom made and the boat itself cost a gazillion to build.

Best of luck
B

 

OSB can be had with WBP adhesives, but it's not commonly seen this way. Other then dynamic strength, weight and shock load resistance, it has really crappy bits of pith, heart, sap laden, bark and other generally undesirable chunks in the "strand" pieces. These tend to rot very easily, wick moisture if the coating/sheathing is breached and add little to the structure. It is what it looks like.

 

I am a water damage and rot damage expert been in the business for 30+ years. OSB is not a suitable material for exposure to water. Its basically left over wood chips bonded together with glue. Its does not rot, just structurally weakens and falls apart. Its ok for homes but not for watercraft.

 

Bronco, OSB can be had with WBP adhesives (as I mentioned above), but typically this is a special order from most suppliers. If left in a moist environment, OSB does rot and fairly quickly too, because of the high percentage of junk wood used in it's construction. We're in agreement in that it doesn't have a place in the marine environment.

 

I'm not a rot or water damage expert, but I have some non-waterproof OSB in the boat shop I had thought about using to make stations for my build. It got wet a few times and has been in high humidity. Aside from rampant mold growth, the stuff was always warped and fell apart completely after getting wet.

I had to pick up loosened wood chips and sweep/shovel some of it up off the floor.

I'd have to agree with Bronco Billy.

 

OSB is a big no for boats. If you cannot afford Marine Ply for your bulkheads find a quality ACX or ABX PTS plywood (plugged, touched, sanded) plugged means all voids in the ply are filled with wood or at least with water proof adhesive. AC or AB means A face B face or C face. X means exterior adhesive is used-water proof. Usually less then 1/2 the cost of marine ply. Another way to save on bulkheads is use a thinner Marine ply with 2-A faces then adhesive on some hardwood strips say 3/8" x 3/4" vertically--even make a design-this will really stiffen the ply and you can do it to both sides if need to.
The strips act as small studs and if on both sides it creats a very strong piece.

 

Years ago mobil home subfloors were made out a wax impregnated OSB ( cALLED FLAKE BOARD in the trades). Held up pretty well but also had formaldihide(correct spelling?) in it and could not be painted over.