got another plywood question

M

michael barnes

Active member
i have asked is a post awhile back about exterior vs. true marine plywood for boat building. the answers i got were all the same, a good marine plywood is superior in every way over regular exterior ply. thats pretty much what i expected.
with that in mind, i would like to build my first small boat, something like the kara hummer, or a htbrid style boat like the ones on the refuge forum. for my first boat, one that will most definitely be replaced in a year (there are several kinds of small skiffs i want to build, and the first one i build will be a "test" boat, to see how well i do), and one especially as small as the hybrids or a hummer, in the 8-12' range, i just cant see spending 300$ or better in marine plywood.
i have taken your advice, and i realize form all the input that marine ply is definintely worth the money. but i would like your opinion on this. is building my first 8-12' boat out of regular exterior plywood i waste of time, and should definitely be built out of marine plywood, or do you think that its sensible to go ahead the cheapest route, for the first time, just to get a feel for it, and figure out how it all works, and then when i know better what i want, build a boat out of top materials?
thanks everybody, i appreciate your time and advice.
 
Mike,
There are a lot of boats being used on the Roanoke River and others right now that have cypress sides and exterior plywood bottoms. They are very simple and cheap to build and are made in a variety of widths and lengths. They are very similar to jon boats. Those that last more than a year are painted annually. These boats are used primarily for fishing fresh water. They are good to fish from because they are stable and quiet. My first boat ever was a death trap made from exterior plywood scraps liberated from a construction site. I left it overboard in a creek and fished and sqirrell hunted from it until it sank during a storm. That was the boat I learned to paddle and pole in as I had no outboard to hang on it.

I know that ther are those on this site that will consider it heresay, but I think you are on the right track for a "first" boat as long as you don't over tax it or expect too much as far as it lasting.

Good luck,
Harry
 
i have asked is a post awhile back about exterior vs. true marine plywood for boat building. the answers i got were all the same, a good marine plywood is superior in every way over regular exterior ply. thats pretty much what i expected.
with that in mind, i would like to build my first small boat, something like the kara hummer, or a htbrid style boat like the ones on the refuge forum. for my first boat, one that will most definitely be replaced in a year (there are several kinds of small skiffs i want to build, and the first one i build will be a "test" boat, to see how well i do), and one especially as small as the hybrids or a hummer, in the 8-12' range, i just cant see spending 300$ or better in marine plywood.
i have taken your advice, and i realize form all the input that marine ply is definintely worth the money. but i would like your opinion on this. is building my first 8-12' boat out of regular exterior plywood i waste of time, and should definitely be built out of marine plywood, or do you think that its sensible to go ahead the cheapest route, for the first time, just to get a feel for it, and figure out how it all works, and then when i know better what i want, build a boat out of top materials?
thanks everybody, i appreciate your time and advice.
Click to expand...


Several things...

I think the notion of a first or practice boat using crappy wood is not sound. Your first boat will take longer to build, but there is ABSOLUTELY no reason that it will be lower quality. If anything you are spending a ton of time on it, it should be quality materials.

If you are going to build out of ACX, think about glassing both sides (inside with 4 ounce to protect against checking). I would consider MDO for any parts you could use it for over regular exterior plywood.
 
Last edited:
thanks for the quick reply. i figure i can build a small boat for about 250$, and if i can get 2 seasons out of it, ill be tickled. i woont be leaving it in the water, and will keep it painted. if i went with marine ply, the cost would easily double, probably more, and it would still be the same, little first boat i made, that i would use for a season or 2 to learn with, until i know exacly what i want and need, and then ill put the $$ into a boat that i am sure is what i want.
 
hey tod, i posted my second reply before i saw your post. thanks for the advice. sorry for my ignorance, what is MDO? thanks again, mike.
 
hey tod, i posted my second reply before i saw your post. thanks for the advice. sorry for my ignorance, what is MDO? thanks again, mike.
Click to expand...


Medium density overlay, it is supposed to be nice and some have used it with good success for boats. Call around to see if you can find it.
 
Last edited:
YES!!! Finally a post I can toss my 2 cents in at! I can tell you not from boat building experience but from a lumber / construction experience. Marine grade plywood when being used for things outdoors will give you a superior performance than a treated ply. depending on the amount of treating of the plywood you purchase. Technically wolmanized or pressure treated ply wood is actually interior plywood who has just been treated with chemicals, usually made of a softer less dense wood. "Exterior plywood" is made with exterior glue but can still have voids and or gaps that could leave you with a weekend structure... Marine grade ply is void free, laminated together with waterproof glue so the layers do not delaminate or spread appart... Even when submerged in water....

So OK say you are going to attempt to purchase the stuff from a box store such as home depot, you may find what you think is a great price, dont go for it only on price. Search out your local lumber yard and buy it from there. They can tell you exactly what it is you are buying before you get it home and regret saving $10 dollars.... The exterior plywood even coated and sealed will end up delaminating in no time. If your looking for a sound, dependable boat I would go for spending a little more money and grab the marine grade... But like I said just my two cents in....


Bridget
 
YES!!! Finally a post I can toss my 2 cents in at! I can tell you not from boat building experience but from a lumber / construction experience. Marine grade plywood when being used for things outdoors will give you a superior performance than a treated ply. depending on the amount of treating of the plywood you purchase. Technically wolmanized or pressure treated ply wood is actually interior plywood who has just been treated with chemicals, usually made of a softer less dense wood. "Exterior plywood" is made with exterior glue but can still have voids and or gaps that could leave you with a weekend structure... Marine grade ply is void free, laminated together with waterproof glue so the layers do not delaminate or spread appart... Even when submerged in water....

So OK say you are going to attempt to purchase the stuff from a box store such as home depot, you may find what you think is a great price, dont go for it only on price. Search out your local lumber yard and buy it from there. They can tell you exactly what it is you are buying before you get it home and regret saving $10 dollars.... The exterior plywood even coated and sealed will end up delaminating in no time. If your looking for a sound, dependable boat I would go for spending a little more money and grab the marine grade... But like I said just my two cents in....


Bridget




thanks, its great to see exactly what each grade is, and all the differences. thanks to everybody else as well.
Click to expand...
 
Last edited:
I wouldn't build a hybrid with marine ply. If you go with marine ply go with a better design too. Just my two cents.
 
I built a pirougue out exterior 1/4" ply I bought at Home depot it lasted about 4 years stored outside on sawhorses .I had just painted it with exterior house paint. It was to me a "disposable" boat. I wasn't sure what I wanted and wanted to spend as little as possible. After the first season with it I had determined it wasn't the boat I was looking for. I am thinking about doing the same thing again this summer but a boat of my own design. It was my second boat build and I have built 3 boats since, all of the others used high grade marine ply and were fiberglassed over. I think if you do not have expectations that the boat will last or be as strong as a boat made of marine ply than whats wrong with that. One thing to consider is that it will take longer than you think to build a boat and if you don't want to, or have the time or money to do it again in a year or two your stuck with what you have... a rotting boat
 
Michael,

I finished a BBIII last year and love the boat. Build with Marine ply and didn't cut corners. Building a boat to keep for a while with quality materials is a great thing and something I will do again.

This year I am tossing around the idea of a Kara things are slow and I have time but dont have a ton to spend. If if do build it I will be using local cut ash for structure and a birch plywood for the plywood. Not everyone agrees on the birch here but if encapsulated in epoxy it should never rot.

Here is a thread on the birch you may find interesting and helpful.

http://duckboats.net/cgi-bin/forum/gforum.cgi?post=46463;search_string=birch;#46463
 
If you build a Kara you can follow the directions and go with ACX. I have one that is 10 years old and still going. The exterior glue is the same as the Marine. The plys are not as nice and will have voids in the ACX. But a skin of epoxy and cloth will keep it giong. If garaged for the off season it will hold up.
The bends in the bow of the Kara are the tight part and I was able to get the ply around it without a problem.
For a boat with bigger asperations than shallow marsh or flooded field work the Marine ply will be better, but cost more.
Ed Askews light weight Kara is another story and uses better grade plys (Door Skins?) and epoxy with cloth to get a stiff but lighter hull.
 
Michael I am all for Marine plywoods but I get your point. The post that Brandon linked to is worth reading. The birch ply is dense and heavy, strong. The down side is it can not stand water. It will quickly delaminate and warp. It is important that you encapsulate the ply with epox and a good waterpoof paint. If you do a good job of that the boat ought to last ten to fifteen years.
The birch ply is used as under layment for floors and doesn't have voids.

The main thing to remember is you have to keep it encapsulated (must be dry or it won't last a year) You will spent more on paint or epox than ply.
 
YES!!! Finally a post I can toss my 2 cents in at! I can tell you not from boat building experience but from a lumber / construction experience. Marine grade plywood when being used for things outdoors will give you a superior performance than a treated ply. depending on the amount of treating of the plywood you purchase. Technically wolmanized or pressure treated ply wood is actually interior plywood who has just been treated with chemicals, usually made of a softer less dense wood. "Exterior plywood" is made with exterior glue but can still have voids and or gaps that could leave you with a weekend structure... Marine grade ply is void free, laminated together with waterproof glue so the layers do not delaminate or spread appart... Even when submerged in water....

So OK say you are going to attempt to purchase the stuff from a box store such as home depot, you may find what you think is a great price, dont go for it only on price. Search out your local lumber yard and buy it from there. They can tell you exactly what it is you are buying before you get it home and regret saving $10 dollars.... The exterior plywood even coated and sealed will end up delaminating in no time. If your looking for a sound, dependable boat I would go for spending a little more money and grab the marine grade... But like I said just my two cents in....


Bridget
Click to expand...


even sounds like Lee....good input!!
 
You must log in or register to reply here.
Back
Top