Re: [bolger] Fishcat and Plywood - Payson & Luan
Just one additional thing. Someone made the comment
that they didn't agree with Payson's comment that Luan
plywood was weak. I'm not attacking that statement in
the "it worked for me" sense in which it was so
appropriately made.
I would guess that Fir as a species is stronger than
Luan, but there is another dynamic: Much 1/4" Luan is
5.5 MM thick, the stuff I am using in Fat Eeek is 5.4
MM. If the Fir is 1/4" it is 6.35 mm. If the species
were the same, and quality simmilar (Fir tends to have
more voids and dutchmen, so who knows), on those
numbers alone I believe, that's 1.63 stiffer for the
Fir, and 1.39 stronger.
Some fir ply looks as though the layers are
1/3x1/3x1/3, so the tranverse core would only be 2.1
mm thick. Fat Eeeks Luan is 1.2mm x 3mm x 1.2mm with
the top sanded layer actually a fraction lower than
1.2mm. What that tells me is that used length wise on
a bottom as you might on say an Elegant Punt, or Fat
Eeek!, the Luan actually has more transverse beef,
which, species aside, might make it stiffer for the
governing walking loads and water loads. If there
were a lot of bulkheads, that break up the
longitudinal ply, then you are back to the greatter
longi strength of the fir.
Same thing has to be considered on those designs where
the bottom is nailled double, and the plywood oriented
with its length accross the boat bottom. Again one
would expect the Fir to come out on top: In the
direction of the greattest unsuported loads, you have
stronger material (I think), in thicker sections, with
more fiber thickness for the surface lams.
______________________________________________________
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that they didn't agree with Payson's comment that Luan
plywood was weak. I'm not attacking that statement in
the "it worked for me" sense in which it was so
appropriately made.
I would guess that Fir as a species is stronger than
Luan, but there is another dynamic: Much 1/4" Luan is
5.5 MM thick, the stuff I am using in Fat Eeek is 5.4
MM. If the Fir is 1/4" it is 6.35 mm. If the species
were the same, and quality simmilar (Fir tends to have
more voids and dutchmen, so who knows), on those
numbers alone I believe, that's 1.63 stiffer for the
Fir, and 1.39 stronger.
Some fir ply looks as though the layers are
1/3x1/3x1/3, so the tranverse core would only be 2.1
mm thick. Fat Eeeks Luan is 1.2mm x 3mm x 1.2mm with
the top sanded layer actually a fraction lower than
1.2mm. What that tells me is that used length wise on
a bottom as you might on say an Elegant Punt, or Fat
Eeek!, the Luan actually has more transverse beef,
which, species aside, might make it stiffer for the
governing walking loads and water loads. If there
were a lot of bulkheads, that break up the
longitudinal ply, then you are back to the greatter
longi strength of the fir.
Same thing has to be considered on those designs where
the bottom is nailled double, and the plywood oriented
with its length accross the boat bottom. Again one
would expect the Fir to come out on top: In the
direction of the greattest unsuported loads, you have
stronger material (I think), in thicker sections, with
more fiber thickness for the surface lams.
______________________________________________________
Send your holiday cheer withhttp://greetings.yahoo.ca
A big THANK YOU for all of your answers to my questions about the
Fishcat and Plywood question. Some day I hope to be able to help
someone like you have helped me. Now all that is left is a couple of
honneydo's and then I can start on the cat. Thanks again,
Terry
Fishcat and Plywood question. Some day I hope to be able to help
someone like you have helped me. Now all that is left is a couple of
honneydo's and then I can start on the cat. Thanks again,
Terry