Ply stability.
 

"Patrick" schreef in bericht
...

I want to put together a stitch and glue boat. But cant afford to get all
the marine ply at once.
If I start stitching the hull together, is it going to warp in the damp
British Autumn air, if I cant put the bulkheads in and glue it for a few
months.
I,ll be building it in an open barn.
Any ideas Patrick.


can't you just put the bulkheads in with a few nails not totaly drivven is
or with some screws???
thats how i temporarily place bulkheads
www.hbeq.com see for youself.
more questions mail
greetz Hilco

Ply stability.
 

I want to put together a stitch and glue boat. But cant afford to get all
the marine ply at once.
If I start stitching the hull together, is it going to warp in the damp
British Autumn air, if I cant put the bulkheads in and glue it for a few
months.
I,ll be building it in an open barn.
Any ideas Patrick.

Ply stability.
 

"Patrick" wrote in message ...
I want to put together a stitch and glue boat. But cant afford to get all
the marine ply at once.
If I start stitching the hull together, is it going to warp in the damp
British Autumn air, if I cant put the bulkheads in and glue it for a few
months.
I,ll be building it in an open barn.
Any ideas Patrick.

Technically, you should not have problems if it is properly
ventilated... and it used to be that way with the Joubert plywood I
used to get. Unfortunately, there is a lot of difference even in
BS1088 from manufacturer to manufacturer. The best stuff I used to get
was made in France, and the local buyers won't buy it anymore. Now we
have this stuff from Morocco and it checks, seems more brittle, and
has lousy color too. Anyway, to your question... You could tack some
temporary battens into the parts to hold the shape, especially on the
edges, or just not cut till you have all the wood if it is a smaller
project. Either way, you will be better to give it light and
ventilation in the barn, just not direct rain.
Scotty

Ply stability.
 

here is my experience with storing/using ply in a damp climate: (can't get
much damper than here in the US Pac. NW)

If is store any ply in outside storage (sheltered from rain) the moisture
content raised to the point that polyester resins don't penetrate/bond
properly. However, if I bring the ply pieces into the heated shop for a
couple days, the surface plys seem to return to a exceptable moisture
content..

I use a moisture meter to verify this and note that in the outside storage,
during cold weather, the moisture content of the surface ply will go as
high as 18 to 20%, while ply that remains in heated storage stays at about
12 to 15%.

If I purchase new sheets of ply, from a stack of sheets, any sheet other
than the top sheet will also be at 12 to 15%.

Bottom line, if your going to have your partially finished boat in an
unheated barn and your humidity is anything like I have here, you will have
to wait until warm weather before doing any taping of seams.


--
My opinion and experience. FWIW

Steve
s/v Good Intentions

Ply stability.
 

Your quite right of course I should just leave all the ply in a big pile
until I have enough for the hull at least. But everyone keeps asking me if I
have started my boat yet so I felt as though I should at least get a couple
of bits of wood together!
But its a good idea to maybe put a few battens or spreaders in to keep it
honest.
Patrick

----------
In article ,
(Backyard Renegade) wrote:


"Patrick" wrote in message
...
I want to put together a stitch and glue boat. But cant afford to get all
the marine ply at once.
If I start stitching the hull together, is it going to warp in the damp
British Autumn air, if I cant put the bulkheads in and glue it for a few
months.
I,ll be building it in an open barn.
Any ideas Patrick.

Technically, you should not have problems if it is properly
ventilated... and it used to be that way with the Joubert plywood I
used to get. Unfortunately, there is a lot of difference even in
BS1088 from manufacturer to manufacturer. The best stuff I used to get
was made in France, and the local buyers won't buy it anymore. Now we
have this stuff from Morocco and it checks, seems more brittle, and
has lousy color too. Anyway, to your question... You could tack some
temporary battens into the parts to hold the shape, especially on the
edges, or just not cut till you have all the wood if it is a smaller
project. Either way, you will be better to give it light and
ventilation in the barn, just not direct rain.
Scotty

Ply stability.
 

I can't see it as being a problem. Even the local building code only
specifies a 1/8 inch expansion gap between sheets of exterior grade plywood
on a roof. Would 1/8 inch in 4 ft be too much?

There are a lots of plywood boats which took longer than a year to build.
As one young woman of my aquaintence said about childbirth, "a lot of
other people have done is successfully".


--
------------------------------------------------------------------------------
William R Watt National Capital FreeNet Ottawa's free community network
homepage: www.ncf.ca/~ag384/top.htm
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Ply stability.
 

Thanks William, It was the possibility of the sheets twisting which I was
more worried about.
Patrick

----------
In article ,
(William R. Watt) wrote:


I can't see it as being a problem. Even the local building code only
specifies a 1/8 inch expansion gap between sheets of exterior grade plywood
on a roof. Would 1/8 inch in 4 ft be too much?

There are a lots of plywood boats which took longer than a year to build.
As one young woman of my aquaintence said about childbirth, "a lot of
other people have done is successfully".


--
------------------------------------------------------------------------------
William R Watt National Capital FreeNet Ottawa's free community network
homepage: www.ncf.ca/~ag384/top.htm
warning: non-freenet email must have "notspam" in subject or it's returned

Ply stability.
 

How about coating it with epoxy? You could do that even before you start
cutting the panels (it's easier that way). Of course, that assumes you're
planning on using an epoxy coating........


"Patrick" wrote in message
...

I want to put together a stitch and glue boat. But cant afford to get all
the marine ply at once.
If I start stitching the hull together, is it going to warp in the damp
British Autumn air, if I cant put the bulkheads in and glue it for a few
months.
I,ll be building it in an open barn.
Any ideas Patrick.

Ply stability.
 

Patrick wrote:

Your quite right of course I should just leave all the ply in a big pile
until I have enough for the hull at least. But everyone keeps asking me if I
have started my boat yet so I felt as though I should at least get a couple
of bits of wood together!

It seems to me that external pressure is the wrong reason to start building.
Build when it suits YOU, not anyone else. It's your money and labor at stake,
not theirs.

--
Regards

Brian

Ply stability.
 

"Matt/Meribeth Pedersen" wrote in message link.net...
How about coating it with epoxy? You could do that even before you start
cutting the panels (it's easier that way). Of course, that assumes you're
planning on using an epoxy coating........

Not a suitable solution. We have this arguement all the time on the
group but epoxy is not waterproof, it is very water resistant but not
waterproof.. Some will say that it indeed is if you put down several
coats and cover with varnish or paint, I will give them that but you
don't want to apply a finish to boat parts until it is done as you
will always find yourself resanding and doing it over later anyway.
Soooo.... putting a surface coat or thin coat to keep moisture out
will be uneffective in this case, moisture will get into the plys. I
think what this guy is worried about, and he should be, is the edges
warping and disfiguring, thats why I suggested temporary thin battens
along the edges until he is ready to stitch to the next panel on the
hull. Kind of like a seam batten boat.
Scotty from SmallBoats.com



"Patrick" wrote in message
...

I want to put together a stitch and glue boat. But cant afford to get all
the marine ply at once.
If I start stitching the hull together, is it going to warp in the damp
British Autumn air, if I cant put the bulkheads in and glue it for a few
months.
I,ll be building it in an open barn.
Any ideas Patrick.