reason for marine ply durability
Just Terry
stuff has such a high resistance to failure to the elements. If you have
some different thoughts please respond. Each laminate is completely isolated
from the other with the layer of adhesive. The adhesive used causes a
complete water barrier. If you seal over the exposed edges of marine ply it
cannot pass water through. WIth only the outer layer absorbing water, it
wont become saturated and hold water that cannot evaporatein a short time.
Exterior grade ply uses waterproof glue but isnt sealed between layers. It
wont have a life anything near what marine ply has. Water will absorb
between the layers and start the rot process. So even if you seal the edges
of exterior ply it will never have a lifespan close to marine. When marine
ply fails it is due to water saturating the inner layers from exposed
edges.(or damage) Since it is sealed between layers the only way water can
escape or have a chance to evaporate easily is through the path it entered.
So if an outer layer fails or is damaged it could consider as an option,
grind down to the adhesive and then add the veneer layer back on. But if it
shows any failure between layers, it may be too far gone to do anything
short of replacing it. Certian circumstances migh make it easier to repair
the outer layer, especially cosmetic purposes than replacing the whole panel
just because of bad weathering or missing chunks. this may not hold viable
if it is a very large area. Please feel free to flame me for voicing my
opinions here.
Michael Neverdosky
quality of that 40 year old ply in todays market.
First the quality of wood is just not available.
Even if good wood is found it is not likely to end
up in plywood.
Second the level of quality control is just not the
same.
Hmmm I wonder what would happen if I found a warehouse
full of 40 yo marine ply?????
There I go, dreaming again.
michael
Auerbach
> You will have a very hard time finding ply of the quality of that
> 40 year old ply in todays market.
> First the quality of wood is just not available. Even if good wood
> is found it is not likely to end up in plywood. Second the level of
> quality control is just not the same.
This notion (which I've seen in other postings) puzzles me.
Wood of 40 years ago was from trees that grew in forests pretty
much the same way trees have been growing since Noah's time.
God didn't decide, during the Eisenhower Administration, to start
making trees grow faster or with lower quality. A tree cut today that is
30 years old should be pretty similar to a tree cut in 1959 that was
also 30 years old when cut. The tree doesn't know that quality has
gone into the dumper.
Second, why do we assume that manufacturing qualilty has gone to hell
since the good old days? My '59 Chevy was a great little car, but it spent
a fair amount of time in the shop as a matter of routine. My '99 is likely
to go 50,000 miles without much more than a few oil changes, even
though its innards are impossibly more complex than my old inline six.
The power tools I buy today are lighter, easier to use, safer and just as
durable as the iron monsters of the past.
Nostalgia is wonderful, and we should admire, cherish and preserve great
examples of boatbuilding craftsmanship of yore. But I suspect that there
was crappy work done, with crappy materials, in the good old days. I sure
found plenty of both recently when I remodeled a home that was built by
"craftsmen" some 50 years ago!
Alex
c...@netspace.net.au
>
> Nostalgia is wonderful, and we should admire, cherish and preserve great
> examples of boatbuilding craftsmanship of yore. But I suspect that there
> was crappy work done, with crappy materials, in the good old days. I sure
> found plenty of both recently when I remodeled a home that was built by
> "craftsmen" some 50 years ago!
The reason that people tend to think old equals better quality, whether
in houses, boats, or cars, is that the best examples last longer on
average - the crap gets weeded out. So, if for example, 90% of wooden
boats built 100 years ago were utilitarian, use it 'til it falls apart
construction, and 10% were built either by hobbyists or for rich people,
guess which boats tend to be the ones we see today! "Oh look 95% of
boats around today, that were built 100 years ago, are works of sublime
beauty, boy they were craftsmen, if only I could have lived then, etc
etc etc"
Chris
Frank Hagan
<auerbach...@pacbell.net> wrotd:
>"Michael Neverdosky" <mneve...@earthlink.net> wrote
>> You will have a very hard time finding ply of the quality of that
>> 40 year old ply in todays market.
>This notion (which I've seen in other postings) puzzles me.
>
>Wood of 40 years ago was from trees that grew in forests pretty
>much the same way trees have been growing since Noah's time.
>God didn't decide, during the Eisenhower Administration, to start
>making trees grow faster or with lower quality. A tree cut today that is
The original poster specified that you would be hard pressed to find
the same quality of wood in a particular product: plywood. It is the
grading and selection of the wood that matters. Nice, vertical grain
douglas fir no longer ends up as 2xs and boards like you see in older
house construction. It ends up at lumberyards marked for us to buy at
a premium. I think it has more to do with the demands of the
marketplace than old verses new growth.
I've heard people say that they simply can't find good quality ACX
plywood anymore; that the grading system has slipped.
Olwyn Morinski
No sir - no way! I am not suffering from a bad case of nostalgia.
There IS a difference in wood today and it has to do with the way it is
grown, the way it is harvested, and the way it is graded. Of course the
trees haven't changed - but the way we grow and harvest them has
changed big time and that changes the wood we get from them. A very
simplified and incomplete explanation follows . . .
Read on and then please do an honest job of re-examining your thinking
on this subject.
Wood in modern "forests", plantations, or "tree farms" or whatever
they're called is tended, thinned, fertilized, pampered in every way
possible to produce the highest VOLUME of wood in the shortest period of
time - not the highest quality. The details vary from place to place
and species to species - but it is typical that plantation managers will
remove "competing" species so as to prevent the cash crop species from
being in the shade. This has at least 2 deleterious effects. For
example, The "competing" or "weed" species often provide nutrients.
Remove them and you destroy the reservoir of nutrients in the soil.
Remove their shade and the cash species grows faster - so its wood is
less dense and defective in many ways - especially for boatbuilding. It
is weaker, softer, cannot hold fasteners or finishes as well, and tends
to rot faster.
With regard to grading - modern grading standards permit far more
sapwood than a few generations back. Sapwood, if you didn't know it
before, is far more susceptible to rot.
Volume-based timber harvesting is reducing wood to a characterless
commodity of mediocre quality. Short rotations - that is, cutting
trees at 60 or 80 years of age instead of at full maturity does produce
more wood - but the wood is crap and you cannot build anything from it
that will last until the next crop is ready to harvest. Do the math -
Planting as practiced in modern plantations can produce more volume
faster - and, if you replace the natural succession of species with
artificial fertilizers you can mask the damage you are causing for a
while - but the soil nutrients are depleted inevitably. More than
simply soil nutrients are depleted or destroyed. There are countless
organisms; microbes and fungi which act as the interface between the
chemicals in the soil and the roots of the trees. They are absolutely
necessary for the metabolism of the trees and they, in turn, are
dependent upon the missing "weed" species for their existence. They
disappear eventually. Then no amount of fertilizer does any good
because the cash crop trees will simply not be able to absorb or
metabolize the nutrients.
Many North American boatbuilding woods are species which live on
relatively nitrogen-poor soils and cannot themselves extract and "fix"
nitrogen from the atmosphere. They depend upon lichens and mosses which
grow ONLY upon the larger and older trees to perform this function.
These old trees are missing from tree plantations and so the nitrogen
cycle is damaged and destroyed.
There are species of wasps and other predator insects which live ONLY in
the high canopy of a MATURE forest. These insects eat pests which would
otherwise damage trees. If you cut your trees while they are still
babies, as in the typical short rotation systems in use today, those
beneficial insects cannot exist because their habitat doesn't exist -
and therefore the pest species are able to multiply without any natural
predators. Next thing you know you read in the papers about some kind
of beetle infestation wiping out whole forests. Almost every time you
hear about such events they are in second growth forests - the forest
that comes back or has been planted after the original forest has been
clearcut. The beetle infestation is always cited by lumber companies
as justification to cut the second growth even faster. They say they
have to cut it right now to "salvage" it or to "protect" the rest of the
forest of crap they're growing. The faster they cut it, the higher the
apparent availability and the lower the price to consumers. (There are
plenty of consumers out there today who are stone-ignorant about wood
and will buy anything) So they buy crap faster - the logging companies
get rich faster - houses and boats rot faster - and there will be
piss-all left to build new ones with when they all need replacing in
about 1/4 of the time that used to be reasonably expected.
I have barely scratched the surface here - but I strongly suggest that
you read and study something other than the propaganda put out by
Weyerhauser and Georgia-Pacific about how wonderful their tree farms
are. Their tree farms produce pulpwood to make paper to print their
propaganda on. And they produce poor quality framing lumber - but forget
about boat lumber - it ain't there. That still comes from old-growth -
which is being liquidated and not replaced.
For a while I owned a house here in B.C. with 2" x 4" Douglas Fir
Rafters, 24" on centre. That house was built in 1912, has stood
through every kind of weather and every kind of snow load and it is
standing today in fine shape. You could not legally build a roof like
that today because you cannot get Douglas Fir which could take the load
or last the time. Look at the building code. That same roof today
would require 2" x 10" rafters, 16" on centre. And those 2' x 10's
would probably be half sapwood. Crapola! This is only one of many
examples I have seen in my life of woodworking.
As for craftmanship and poor manufacturing - Sure there were bad actors
100 years ago, and there are slobs today and there always will be poor
workers and poor designers. But given the poor quality of wood that
people have come to accept as standard today - what would inspire a
person to do good work with it? What would be the point? The old
saying "You can't make a silk purse out of a sow's ear" applies here.
You cannot design or craft quality into crap.
We can do good work with the little old-growth wood still available to
us while it lasts - but our kids won't have that for many generations
longer.
Please learn a bit more about wood. It is not a "product" like
concrete, aluminum, or epoxy. It is the outgrowth of quite complex
living systems and it can turn out useful or useless depending on how it
is treated along the way. If that is too much for you to handle, then
work with something a bit more predictable - no judgement upon you - but
please give us a break. One piece of wood is not like another. Don't
repeat logging company propaganda - consider the source and consider
their motives. Don't fall for that sanctimonious stuff about how trees
have been here forever, growing just as wonderfully as they did in the
Garden of Eden. We are clearcutting the Garden of Eden.
Thanks for paying attention.
Marty at Elk Lake
> "Michael Neverdosky" <mneve...@earthlink.net> wrote
> > You will have a very hard time finding ply of the quality of that
> > 40 year old ply in todays market.
> > First the quality of wood is just not available. Even if good wood
> > is found it is not likely to end up in plywood. Second the level of
> > quality control is just not the same.
>
> This notion (which I've seen in other postings) puzzles me.
>
> Wood of 40 years ago was from trees that grew in forests pretty
> much the same way trees have been growing since Noah's time.
> God didn't decide, during the Eisenhower Administration, to start
> making trees grow faster or with lower quality. A tree cut today that is
> 30 years old should be pretty similar to a tree cut in 1959 that was
> also 30 years old when cut. The tree doesn't know that quality has
> gone into the dumper.
>
> Second, why do we assume that manufacturing qualilty has gone to hell
> since the good old days? My '59 Chevy was a great little car, but it spent
> a fair amount of time in the shop as a matter of routine. My '99 is likely
> to go 50,000 miles without much more than a few oil changes, even
> though its innards are impossibly more complex than my old inline six.
> The power tools I buy today are lighter, easier to use, safer and just as
> durable as the iron monsters of the past.
>
> Nostalgia is wonderful, and we should admire, cherish and preserve great
> examples of boatbuilding craftsmanship of yore. But I suspect that there
> was crappy work done, with crappy materials, in the good old days. I sure
> found plenty of both recently when I remodeled a home that was built by
> "craftsmen" some 50 years ago!
>
> Alex
Michael Neverdosky
>
> "Michael Neverdosky" <mneve...@earthlink.net> wrote
> > You will have a very hard time finding ply of the quality of that
> > 40 year old ply in todays market.
> > First the quality of wood is just not available. Even if good wood
> > is found it is not likely to end up in plywood. Second the level of
> > quality control is just not the same.
>
> This notion (which I've seen in other postings) puzzles me.
>
> Wood of 40 years ago was from trees that grew in forests pretty
> much the same way trees have been growing since Noah's time.
Trees grow in the same way given the same conditions.
There is a big difference between wood from trees in an old grouth
forest
than from a plantation.
The trees in the plantation are given space, light and water such that
they grow fast. Fast growth = looser grain structure and less strength.
There are other factors as well, you might want to consult some of the
books on wood.
You also might consider that the wood in the ply from 40 years ago
probably
came from a much older tree than the wood of today.
> Second, why do we assume that manufacturing qualilty has gone to hell
> since the good old days?
I don't have to assume. I walk into a lumber yard and look.
30 years ago I would buy 2x4s that were straight with no checks, knots,
splits or bark. Today such 2x4s are simply not available.
The exterior ply I bought 30 years ago was better than most of the
domestic
marine ply I buy today.
This is not true of everything.
Lots of industries are advancing and growing, but wood is on the decline
and has been for a long time.
Ask any boatbuilder who is working in wood and who has been around for
more
than 30 years.
It is very hard to fine really good wood today.
michael
Robert Lundy
Essentailly everytjing he says jibes with what I know. I grew up in the SE
USA and lived ( and played) next to tree farms for GP, Weyerhauser nad
International paper. Remember, what most of us try to at leat build part of
our boats out of is plywood. The goal of plywood manyfacturers is to make
really good underlayment or exterior sheathing that will rot before it
delaminates.
Marine ply to most american manufacturers is to be used as flooring (covered
with chopped glass and polyester) in runabouts and for stringers for the
same. American Marine ply is not designed for our intended use, there is no
volume in that. thats why we all lust after okume and BS1088 at $60-100 per
sheet.
Robert Lundy
Olwyn Morinski <ol...@home.com> wrote in message
news:3836459C...@home.com...
C. Drues
my existance, piss poor hemlock.
Yet even that is a joy to work with compared to the manufactured
engineered, osb, currently pushed at the lumberyard. Sure you can do
marvelous things with sawdust flakes and resin but it isn't even
comparable with the real thing,quality wood.
Colin Brookes
>
>
> No sir - no way! I am not suffering from a bad case of nostalgia.
> There IS a difference in wood today and it has to do with the way it is
> grown, the way it is harvested, and the way it is graded. Of course the
> trees haven't changed - but the way we grow and harvest them has
> changed big time and that changes the wood we get from them. A very
> simplified and incomplete explanation follows . . .
>
> Read on and then please do an honest job of re-examining your thinking
> on this subject.
Hi Olwyn,
I think your post is about the most informative on the background history of
available wood materials that I have read in many a year.
I have mentioned several times in this news group that the material
available today is not the same. And in most cases is no longer durable.
As an example......pre 1950's Mahogany was a durable material available from
Honduras. The timber was felled and the logs often remained in salt water
for many years before being shipped, cut and stillaged then put out to air
cure before reaching the hands of the craftsman. What is sold now may only
be of a similar species, and likely will have come from a different area
(where the composition of the soil is different and therefore also the
wood). And finally is shipped instantly to a mill where it is kiln-cured to
end up with the customer in less than a handfull of months. Some material
is even enzyme pressure cured to shorten the process. Thanks again Olwyn.
regards
--
Colin Brookes
Hartley & Brookes Associates
Hartley & Brookes Boat Designs Ltd
Hartleys Boat Plans Ltd
snailmail: P.O.Box. 33-1094. Takapuna. New Zealand
voicemail: (09) 624 1214
faxmail: (09) 624 1199
emailbusiness: hartle...@xtra.co.nz
emailpersonal: co...@xtra.co.nz
webmail: www.hartley-boats.com
www.ferroboats.com
In Auckland 'The City Of Sails'.
In New Zealand 'The home of The America's Cup'.
sailor
lumber chain, United Building Centers. During that time I worked for
awhile at one of their stores in Western Montana. You cannot believe
the difference in quality of both lumber and plywood in just 30 years.
I was there during the great "douglas fir" demise. In about 1973,
douglas fir, (which was our main stock framing lumber) started to
disappear. The Japanese were controlling most of the old stand timber
stock and were transporting the good doug fir logs to ships off the
west coast of the US and manufacturing plywood. All we could get was a
mix of fir and larch, or that horrible hemlock for construction grade
lumber. It caused problems with architects, builders and designers
because "what had been the norm" in structural material was changing.
Plans that formerly required 2x8 floor joists now needed 2x10,s.
Grading requirements were lowered to increase availability and what we
are now left with in the 90's is stock that would have been classified
as "culls" back then. This is why "engineered" lumber is so popular
now. It is the only cost effective way to build a good strong
structure. Now the plywood we buy is "nominal" thickness. I wanted a
sheet of 3/8" ply for some bulkheads the other day and stopped at a big
chain and their 3/8 was a 1/16th under sized. This is a trend that
will eventually filter down to the "real" lumberyards eventually. It
is something we will all have to learn to live with.
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Yan Stambouli
I haven't read so much valuable opinions and information, in so few lines,
in along while.
Best Regards
Yan Stambouli
Pat Ford
wrote:
<memgasnip>
>Dear Alex and others who believe that one piece of wod is like another.
>
>
>have been here forever, growing just as wonderfully as they did in the
>Garden of Eden. We are clearcutting the Garden of Eden.
>
>Thanks for paying attention.
>
A story-which may be BS-but is still a good story.
During examination of a building at Oxford or some other ancient
English site, it was discovered that some major beams had a severe
beatle infestation. The visitor, looking at the huge oak beams asked
what are you going to do now.
The reply was that we will replace the beam with material from the
forest which was planted at the same time the building was erected
several hundred years ago.
Antique and Classic Boat Society
Pacific Northwest Chapter
Free Classic Boating Ads for All
http://www.halcyon.com/pford/acbsx.htm