Marine grade plywood is the most suitable for building canoes, preferably with a WBP rating, which means the adhesive used has been tested in boiling water to prove its ability to withstand moisture without delamination. AC grade plywood, a lower-quality option, can also be used for canoe construction. However, it is important to note that AC panels can have open and exposed defects on the C-side.
The simplest way to build a plywood canoe is by creating a pirogue canoe, which can be made out of three sheets of plywood. Marine-grade plywood is nearly 100% waterproof and ideal for building piers, docks, and boat hulls. Regular plywood requires additional sealing, while AC grade plywood can be used for boat construction.
Exterior-grade plywood is graded based on the quality of veneers and the size and number of permissible voids and patches. Grades A-C are the most common. To be suitable for marine use, it is recommended to use AC exterior grade plywood, glass cloth, and epoxy on the entire exterior, and only epoxy on the interior.
For boat construction, it is feasible to use exterior-grade plywood, but coating it with epoxy is highly recommended. Epoxy provides a waterproof finish, and the American Plywood Association (APA) recommends treated plywood for best performance in boat manufacturing.
Okume plywood is excellent for being light and strong but not rot resistant. For building a boat, true marine grade plywood is likely to provide the finish and water resistance needed. Any exterior plywood will do, as long as both sides are glassed. Okoume is the most common choice for small-boat construction due to its softness, flexibility, and lightness.
📹 Test Inexpensive Plywood for Boat Building & Boats I’ve Built
I test inexpensive non-marine plywood bought at Lowe’s and Home Depot for boat building, show the boat’s I’ve built with this …
What is the difference between marine plywood and regular plywood?
The Benefits of Marine Plywood. When exposed to water or high humidity, marine plywood exhibits excellent resistance to rotting, shrinking, and warping. This enhanced water resistance is achieved through the construction process. While regular plywood is typically made using three glued-together plies of wood, marine grade plywood can be constructed using as many as five or more layers, bonded with waterproof adhesive. This construction method ensures optimal strength and durability, even in marine environments.
Applications of Marine Plywood. As the name suggests,marine plywoodis primarily used in marine applications such as boat building, yacht construction, and other water-related projects. Its ability to withstand moisture and its high strength make it an ideal choice for structures exposed to water, including docks, piers, and outdoor furniture in coastal areas.
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Can you use regular plywood on a boat?
Pressure-treated plywood and lumber do a good job for their intended purpose. But for boat repair and building, I would shy away from them.
By using WEST SYSTEM Epoxy with marine-grade or non-pressure treated exterior-grade plywood, you can make economical, long-lasting repairs to your boat. Encapsulating the wood in epoxy and using it to seal any holes you drill into the wood results in repairs that can outlast the original plywood by far.
An example of a successful bond. The bonding of the epoxy to the plywood was stronger than the bond of the wood fibers to one another.
You can see the wood fibers still attached to the end of the 2×4.
What type of plywood is best for outdoor use?
Marine Plywood. Marine plywood is the highest quality option, comprising a knot-free structure. The only plywood on the market to be employed nautically, this highly durable plywood is engineered with waterproof glue making it simply unrivalled when it comes to resisting water damage and rot.
To give you an idea of its durability, marine plywood is specifically optimised for submersion in water as part of a boat’s hull.
Depending on the grade and treatment used, hardwood plywood can be applied externally in humid conditions as well as in interior applications.
Is AC plywood marine grade?
There are a number of species of wood used for marine grade plywood. Douglas Fir is certainly the most popular but other species are often used in marine grade plywood. You can get the same performance from exterior AC plywood in nearly all cases.
Marine grade has no natural decay resistance. It has no chemicals added to enhance decay resistance, unless it has been subsequently pressure treated. Marine grade has no special waterproofing in or on the wood.
Most boat builders that still use plywood in the construction of the transom in a fiberglass boat use AC plywood. Nearly all plywood that is incorporated into the fiberglass construction of a boat is very likely AC plywood.
There are certainly many applications in boat construction that we would recommend Marine Grade plywood but when it is going to be encapsulated in fiberglass AC is a much cheaper alternative that works just as well.
What plywood for outdoor use?
When it comes to exterior plywood, there are a variety of types to choose from, with CDX and ACX being the most common. The X marking on the plywood denotes its use as exterior plywood, with the first two letters indicating the construction grade. A denotes a premium grade that is used for higher-end applications, while CDX is a more affordable construction grade option that is still sturdy and durable.
Exterior plywood can be made from a variety of materials, including veneers, high-density hardwood, or light hardwood.
With so many options to choose from, it’s important to select the right type of exterior plywood for your specific needs.
What is the difference between AC and CD plywood?
“CD” and “AC” refer to the physical properties of veneers used for the face and back of the panel. A visual comparison between the two panels shows that the AC panel has a smooth face with few pin-knots or repairs. By contrast, the CD panel is a much rougher panel. Both its C-face and D-back are unsanded and will have large knots. Plus, the D-back can also have some voids where knots have come out.
There is a common misperception that the X indicates a panel graded for exterior use. This is not the case. The X does not mean that the panel is an exterior grade.
As we now know, the “X” denotes the use of an exterior grade adhesive to join the panel’s veneers together. As all plywood panels utilize exterior grade glues, the X does not offer any distinguishing information about the panel. Yet, it remains in building industry jargon as a legacy of pre-performance-based industry standards.
What material is best to build a canoe?
Primarily, Carbon is used to build the lightest possible weight canoes. Carbon’s rigid hulls are also the most efficient of all materials as the materials passes through the water with the least amount of resistance.
COMPOSITE CANOES. “Composite” isageneric manufacturing termmeaning “not plastic.” Composite canoes can be Fiberglass, Kevlar, Carbon Fiber or a combination of any or all of these materials. Let’s discuss the different materials & manufacturing processes briefly.
FIBERGLASS CANOES– LOW TO MODERATE COST & MODERATE CARE. Fiberglass is themost common materialused in canoe manufacturing. Canoe quality can vary widely from cheapest to medium to excellent, as3- basic quality&price point levelsexist:
Cheap fiberglass canoes are made by sprayingsmall pieces of fiberglasscalled‘chopped fiber’mixed with cheappolyester resininto a gel-coated mold. Chop fiber provides little structural integrity, thus canoe hulls tend toflop up & downas you paddle. The canoe industry refers this movement as‘oil-canning’and its repeated action quickly destroys the hull. To minimize oil-canning some manufacturers use lots of resin to bulk up and stiffen the hull, which adds significant weight.
Do I really need marine plywood?
Marine plywood is recommended for any plywood application where the timber will be directly immersed in water for a period of time such as boat building and other marine activities.
In most instances though, an external rated ply is a suitable alternative for applications requiring general moisture resistance. This includes joinery in kitchens and bathrooms, external soffit areas, childcare projects and similar applications.
WHAT IS MARINE PLYWOOD?. Marine plywood is specifically designed with structural strength for greater impact resistance as well as to absorb the effects of water movement and pressure, marine plywood is manufactured to the very highest standard with both ply faces being A grade veneer and totally defect-free. Examples include Hoop Pine Plywood meeting Australian Standard AS/NZS2272; or Pink Marine Ply meeting British Standard BS1088.
IS MARINE PLYWOOD WATERPROOF?. Whilst marine plywood isn’t waterproof, it’s a type of plywood which can deal with moisture. Contrary to what you’d expect, marine plywood is not in itself waterproof but rather a quality plywood made with waterproof glue.
What is AC plywood used for?
AC and BC plywood are sanded plywood with premium faces that are specially designed for cabinetry, furniture, paneling, shelving, and other applications where a knot free product is required.
-AC Radiata plywood will be a mostly clear face with only a few eraser sized knots.
-BC Yellow Pine plywood will be a mostly clear face with knots up to 1″ in diameter.
Can AC plywood be used outside?
ACX plywood is intended for indoor or outdoor applications where resistance to weather and water is necessary.
Marine Grade Plywood. Marine plywood is the highest grade of plywood. Marine plywood is available in the following grades: A-A, A-B, and B-B. It is usually made from Western Larch or Douglas Fir wood. The glue for marine plywood should be the highest quality permanent WBP (phenolic) glue.
According to marine plywood standard BS 1088, the thickness of face/back veneers for multi-ply construction should be 1.3 to 3.8 mm. For three-ply construction, the thickness should be about 0.5mm. The quality of the veneers in marine plywood is better than that used in exterior grade plywood. There should be no defects (except sound pin knots) in the face or the back of marine plywood.
What type of plywood for canoe?
This boat is made from one sheet of 4mm marine ply for the sides, one sheet of 6mm marine ply, for the bottom and some sticks, fibreglass and epoxy to stop the thing from falling apart and to give yourself somewhere moderately comfortable to sit.
Most of the layout for this example comes from free sources on the web which I will include reference to where I deem I feel like it, but the main one is the lazy weekend canoe from the Toledo Community Boathousetoledocommunityboathouse.com/plans.htm This design is 6/7 of a Lazy weekend canoe, being 12 rather than 14 inches high and built using only 2 sheets of plywood instead of 3.
The canoe is a basic plan intended for two people and fishing gear on calm waters. Emergency floatation will be something like pool noodles tied under the seats and a beanbag cushion for the center. The back seat has a low back rest but the front is intended to be used in reverse when paddled single handed.
📹 My Homebuilt Plywood Flat Bottom Canoe and Open Top Kayaks
A video outlining the construction of my Plywood Flat Bottom Red Canoe in 2017 and my Plywood Flat Bottom Blue and Grey …
Based on articles like yours, I built a 6′ cruiser for fishing. It holds one adult and sits in less than 2″ of water. It’s 32″ wide and uses a trolling motor. My son takes it out in fresh water lakes and it holds up fine. Not a single leak. One layer of epoxy inside and three layers outside. No glass – no paint. Titled and registered. The transom is 1/2″ and 1/4″ epoxied together.
I stumbled upon your article searching for the cheapest plywood I could use to build a boat. I’m a carpenter by trade, and I work on waterfront mansions. We use a lot of finish grade plywood for our projects and I’ve noticed a wild amount of variation in quality (like gaps between the laminations, or the weight of the sheet when carrying into the house from the delivery truck). I also attempted to build doors for a lean to shed I built off the side of my house by gluing strips of birch plywood together in hopes it would straighten out the warped plywood I used for this project, I sealed it with clear coat but still got major delamination in a short period o time. I saw multiple articles showing birch that had sat outside for a long time, and held up. That was not the case for me, and based your article, the durability outside seems to depend greatly on the piece of wood your using. I suspect marine grade ply has much higher qaulity control standards and holds up as well as the best example of of lesser grades of ply that you get from big box stores, but you can also get a sheet that slipped through looser QC and will delaminate.
I’ve stalked your article’s and those of Mark Vickers for so long my wife thinks I have a boat building obsessive disorder. She finally said, “Build one already! Stop thinking about it.” So I bought Walts LYS plans. I’m a little concerned that I will wish I’d built a Vbottom after getting banged around on the water but I like the easier flat bottom build for my first boat. There is 4’X10′ MDO at a local plywood specialty store that I’m planing on using. Comments about MDO? I really appreciate your work and time putting up with the comments/questions. Reading through the comments section is exhausting. I read that you used Raka 127 resin with 350 non blushing hardener. I read that Walter recommends Sikaflex and Mark Vickers likes PL Premium. What are your feelings on those adhesives? I live in Washington State and am about to start my LYS build. Temps 50-70, for the next month and then <60 for 2 months. I will be working outside and using tarps to protect my project as the colder wetter weather sets in. I know the temps in Texas are much different. Should I consider different Epoxy in a cooler/wetter climate than those that you listed, and should I buy some thicker epoxy for fillets etc. Also, any must have tools that you would recommend. Radom orbit sander, angle grinder, etc. I've got a circular saw, table saw, jig saw, angle grinder, router, and reciprocating saw, chisels, three drills and $1400 dollars saved to start me off. I think I'll need to get a random orbit sander. Hope to hear from you. Thanks. Sandy
Beware- I did this test better than you did on luan underlayment. I soaked a piece in a sealed jar for MONTHS and when I took it out, it was still good- even when I wrenched it to separate the plies BUT! the thin outer red Philippine mahogany ply looked a bit more inclined to come apart than the rest. I built the boat bottom with it anyways and after a couple years that outer ply began to delaminate in several places forcing me to lift those areas up and put epoxy under them to seal them back down. I have to now be always on the look-out for it as it has happened more than once in several places along the chine for instance. You will have the same problem inside the boat bottom where water sloshes around as well. Also- regarding AC plywood, Douglas Fir companies generally use the same phenolic or similar marine quality glue for their non marine ply as for their marine plywood- the difference being special attention to no voids. It does not pay for them to be switching back and forth between glues. BUT! Yellow Pine plywood by FAR the most common is another story entirely. To my knowledge they all use urea formaldehyde glues. There is a very good boatbuilding glue website on the subject here: christinedemerchant.com/adhesive-glue-urea-formaldehyde.html#:~:text=Upon%20addition%20of%20water%2C%20in,not%20used%20for%20marine%20plywood. It states that it hydrolyzes in warmer temperatures with water and says: “For this reason it is not considered waterproof but rather water resistant and is not used for marine plywood.
That is not a test…it doesnt incorporate rot performance over longer periods and it doesnt compare to marine grades. The reason experts stress marine ply is that expert experience is more than running the boat a couple years of light use. Experience involves seeing how boats wear, and respond to typical dings, pokes, rubbing and abrasions over decades. Epoxy is NOT waterproof in two ways…water vapor can go through epoxy/glass and small dings can let water into the ply, but inhibit evaporation….so some areas can NEVER fully dry. Marine ply is more than the glue – its more plys and better plys. It doesnt make sense to use cheaper ply given the overall cost of boat material and building time. Spending an extra $400 on plywood is the cheaper choice over the life the boat. When you factor in labor the difference is meaningless…unless you want throwaway boats.