Marine Vs Exterior Plywood
John Matheson
Mark Spina wrote:
>
> In <54eamb$h...@scratchy.mis.ca> mar...@mi.net (D. Marier) writes:
> >
> >Marine Vs Exterior Plywood
> >
> >In Canada the manufacturers do not make marine plywood they produced
> >exterior plywood. According to the Canadian Manufacturers there are
> >no differences. The glue used is waterproof for exterior, interior or
> >marine plywood.
> >So if we want plywood labeled “Marine” we have to get it from the
> >Netherlands and paid big bucks for it.
> >In theory the Canadian Manufacturers claimed no difference. In
> >practice, a boat build with marine plywood will outlast one made with
> >exterior plywood. So what is the differences, the Dutch have a 20
> >year's warranty ( for what its worth) and they states that the glue is
> >not the only thing. After gluing the Marine plywood is soaked in
> >chemical baths and cured according to manufacturing procedures??
> >
> >Well is this true? I do not know and I would appreciate any comments
> >before spending the extra money..
> >
> >Denis Marier
> >
> >mar...@mi.net
> >Rothesay, New Brunswick
> >Canada
> >
> >
> The difference between the two is marine ply uses whole piece veneers
> with no voids and the exterior ply uses spliced together veneers on the
> interior with some voids allowed. If used in a marine application the
> voids could cause a compression type failure. Other than that the
> veneers and glue used are the same. Ext ply is usually good enough for
> interior bulkheads and such but you should always use marine grade for
> boat hulls, etc.
>
> Mark Spina
> msp...@ix.netcom.com
>
>
I agree with Mark Spina 100%
JM
D. Marier
Mark Spina
Ed Rich
It has been my understanding that the only difference between "Marine"
plywood and "exterior" plywood ois the fact that the inner plys do not
have any voids in them. I built a 16 foot sailboat out of exterior
plywood in Biloxi Mississippi in 1963 and it is still there and still
going strong. I made the stem out of a piece of cypress but otherwise
the whole hull except for the seats was of exterior plywood and the
boat was assembled with brass screws, bronze boat nails and water mix
water-resistant glue.
John Ongtooguk
Ed Rich (edr...@halcyon.com) wrote:
: It has been my understanding that the only difference between "Marine"
: plywood and "exterior" plywood ois the fact that the inner plys do not
: have any voids in them. I built a 16 foot sailboat out of exterior
A general construction manual that I have states that exterior
plywood used as siding, such as T-111, has an average life of
about 20 years. I tend to agree based upon what I've removed
from our house that was built in '79, where I could easily break
up the 5/8x4x8 panels by hand lengthwise. I very much doubt that
the siding received as much care as your boat, but some panels
that I replaced have already checked rather badly, even after
caulking voids, double priming the grooves and edges, priming
all around, caulking joints, and painting the exposed surface.
What do you guys do to make it last so long on boats ?
John Ongtooguk (jo...@vcd.hp.com)
Steve knight
edr...@halcyon.com (Ed Rich) wrote:
>It has been my understanding that the only difference between "Marine"
>plywood and "exterior" plywood ois the fact that the inner plys do not
>have any voids in them. I built a 16 foot sailboat out of exterior
>plywood in Biloxi Mississippi in 1963 and it is still there and still
>going strong. I made the stem out of a piece of cypress but otherwise
>the whole hull except for the seats was of exterior plywood and the
>boat was assembled with brass screws, bronze boat nails and water mix
>water-resistant glue.
Well thqat was in 1963 I do not think it would be the same today.
"Tools are made to be used and great tools are made to be used by great craftsmen"