marine grade plywood

[Souper]

i was wondering if anyone used it or if even it would be any good
thanks

[KCStudly]

On TPCE I'm using marine spec Okoume 5mm for the floor top and bottom skins, the wall inside skins, ceiling panel, and all of the cabinet panels.

The outside skin will be sealed in canvas (or maybe epoxy fiberglass)... foamie hybrid style.

[Souper]

On TPCE I'm using marine spec Okoume 5mm for the floor top and bottom skins, the wall inside skins, ceiling panel, and all of the cabinet panels.

The outside skin will be sealed in canvas (or maybe epoxy fiberglass)... foamie hybrid style.

ok cool but i dont understand what you mean sealed in canvas

[Shadow Catcher]

Marine grade is the Rolls Royce of plywood, no voids best glue. Best choice!

[KCStudly]

If you look down under the "Build Journal" section of the forum you will see the "Foamie" section.

A member here, GPW (I like to call him the godfather of the modern Foamie Movement) has promoted a method of building that is a combination of what modern RC foam airplane craftsmen are doing and what old school wooden boat builders have done for years. The idea is to use very little wood so there is nothing to rot if/when leakage occurs. Foam is lighter and cheaper than wood, so it is thrifty. The technique uses cotton canvas or duck cloth glued directly to the foam using Titebond II (TB2) glue or exterior latex paint (like Glidden Gripper), either by coating both the foam and canvas, or by saturating the canvas. Since the glue or paint is water resistant/proof, it makes a very economical outer skin that provides strength similar to fiberglass reinforced epoxy ("The Sock Effect"). A lot easier to do for people who are not comfortable or familiar with the idiosyncrasies of using fiberglass techniques.

My build, The Poet Creek Express (TPCE) is a combination of this technique and the more traditional stick built wooden construction because I want the warmth of the wooden interior and did not want to try and apply the canvas (or fabric) from the inside. Plus I wanted lots of inside cabinets and a galley hatch, and I felt that I needed the strength and stability of the extra wood.

Big Mike, the forum owner, had a terrible experience with plywood delamination on a young camper, causing him to deconstruct it after only a season (or two?), and I did not want to risk a similar fate after going to so much effort and expense to build my custom trailer frame. So I went with Okoume marine ply and rot resistant cedar for all of the wood in my cabin structure. The interior cabinet frames and front roof arches are maple hardwood, but those are all interior features. The galley hatch ribs are Red Grandis, which is similar to Mahogany.

Definitely not the most thrifty materials to build with, but remember Mike's motto, "The quality is remembered long after the price is forgotten, so build your teardrop with the best materials..."

The only regular b/c fir ply that I have used so far is the base of my tongue box (small piece of 1/2 inch), but that will be fully encased by the canvas and paint.

My advice is to read all of the 'Build Journals', all of the 'Trailer & Chassis Secrets', all of the 'Teardrop Construction Tips & Techniques' threads that you can stand. If you want to go thrifty and/or very light weight, consider reading the 'Foamie' section and take the time to read through "The big Thrifty thread".

It is way better to make an informed decision when considering taking that huge step of committing to a TD build. It is not a commitment that should be jumped into without proper consideration. Even the most simple and economical builds end up being more of an undertaking than most builders realize.

[rowerwet]

Marine grade is spendy, if you have the money and a good supplier, go for it. I used a brand of luan underlayment from Lowe's that I know has been proven on many cheap boat builds. Of course now Lowe's is slapping the label for this good brand on cheap china made garbage so I don't recommend it anymore. (if you can make sure it is superply, or sureply, the real stuff from patriot, it's good enough for me, but more than one person has found the patriot label over some garbage brand label)
In boat building on the cheap it is recommended to cut a small piece of the plywood and boil it for 10 minutes. If it delaminates, it isn't safe for boat building as the glue is not water proof. For trailer building the same test would let you know what is acceptable, however it won't let you know about voids where they cut knots out or didn't quite get the next sheet stuck to the edge of the last one in one layer. Around here Home Depot doesn't sell anything I would use outside the house in thicknesses for boat or TD building , on the boating sites I'm on may people are finding the independent lumber yards actually have good 1/4, 3/8, and 1/2 plywood, while the big box stores have more and more junk. (thick center ply with two veneer layers to make 1/4" plywood, light colored glue (most likely not waterproof))
Marine Ply will leave no worries about water proof glues or voids, you spend over three times the money per sheet though.

[jonw]

I only use marine plywood for all exterior surfaces and usually for interior as well. Absolutely no worries if/when leaks happen.

Find a lumber supplier for boat builders in your area.