Tortured plywood designs

[PAR]

Yes, there is a measure of how far plywood can be tortured. I have a list of radiuses I can expect different thicknesses and types of plywood can reliably bend to, before rolling sheer and interlaminate issues crop up. The there's the experience thing. I can usually over bend plywood, past my guide lines, using my ear to tell me when I've reached the maximum limits of the plywood's tolerance on this particular radius.

The list can be long, because it shows each size (1/4" on up) in long and cross grain orientations, also different species and veneer counts. For example a 3 veneer sheet of Douglas fir can bend further (tighter radius) then a 5 veneer sheet. The list includes Douglas fir, Okoume, Meranti and Saple. The "compound sheets" (faced plywood) should be judged by it's interior veneers.

Anyone interested in this list, email me and I'll send a copy. Of course, I'm not responsible for any cracked or broken plywood, bent to these radiuses, other then to say, I've successfully bent pieces to these dimensions previously enough to warrant including them on the list.

[ancient kayaker]

Originally Posted by apex1

Let me play with it.

Richard: did you need the FreeShip file for that? It is attached if you need it. You will notice that the 2 sides of the hull are separated by about 3/8" so the plank developments allow for the keel and stems.

Originally Posted by ancient kayaker

Richard: did you need the FreeShip file for that? s.

Of course Terry. thanks...

But will not do it before Monday or Tuesday Ok?

[dskira]

One good way to torture the ply wood, yes plywood not foam, is to take okume ply, and soak copiously with alcohol and quietly take pressure on the ply on a very good male jig, or in a female deck jig (like the Tornado, but this is another technique) and bring it to it's unatural shape. Fasten in order to segragate the bulges, and then come from outside each bulges to the center with the fastening.
You end up with a smooth shape.
I built a lot of little boat like that, it's fun, quick and it looks great.
Compound shape in larger boat can be done repeated the process until the scantling is met. The volatility of the alcohol allow the ply to be glued. The choice of sheathing is not important, everybody has is own soup.
In tortured ply, it is ply involve, the rest is cosmetic.
RWatson, you are not correct. Ply is ply, foam is foam. Richard is right on this one.
Cheers
Daniel

[rwatson]

Originally Posted by dskira

RWatson, you are not correct. Ply is ply, foam is foam. Richard is right on this one.
Cheers
Daniel

Good grief man - are you still rabbiting on about my harmless comments.

For the sake of you rabid ranters the orginal post - yes the orginal post!!

quote " I thought the market would be inundated with designs for the new method"

So, in the spirit of good natured discussion, I comment on WHY the world is not "inundated" - and I get all this grief about straying off the subject.

We need a few people who think before putting their fingers in gear !!!

[dskira]

Originally Posted by rwatson

Good grief man - are you still rabbiting on about my harmless comments.

Yes
Just kidding
Cheers
Daniel

[fabrice]

Sorry to interfere, I'll just post my newbie and amateur question :
ply is now available "foldable".
One could use it instead of torturing standard ply, couldn't he ?
hum, foldable is not the accurate word : bentable maybe.
Like that : (sorry, french adress)

http://www.bois-et-parquets.com/prod...ntrable,14.php

[ancient kayaker]

Fabrice: flexible plywood is available, it has special laminations and grain directions which make it very easy to bend in one axis, but still stiff in the other direction. It is used for round shapes in furniture and other applications. When 2 layers are glued together it becomes stiff like ordinary plywood.

Babelfish translation:

Fabrice : le contre-plaqué flexible est disponible, il a les stratifications et les directions de grain qui le rendent très facile à faire plié à un axe, mais toujours le stiff spéciaux dans l'autre direction. Il est employé pour des formes rondes dans les meubles et d'autres applications. Quand 2 morceaux sont collées ensemble il devient raide comme le contre-plaqué ordinaire.

[fabrice]

ha ! FLEXIBLE ply
sorry about that !
not always that easy to translate technical datas !

Thanks anyway.
So, you just can't work it both axis at the same time, it's just like the average ply ?

[gonzo]

It bends easier in one axis. You could torture bend that plywood too.

[Steve W]

I dont think that bending plywood is exterior bonded so check that out before you get too excited.
Steve.

[fabrice]

Originally Posted by Steve W

I dont think that bending plywood is exterior bonded so check that out before you get too excited.
Steve.

hey, stop reading my mind, that was my next question !

[ancient kayaker]

Flexible plywood will bend much more than regular plywood in one axis, it is rather stiffer in the other axis but not much. However the stiffer plies are thicker and will break before regular plywood would.

If I wanted a curve in both directions that regular plywood could not do, I would use strip plank construction, at least on the curved portion of the hull.

[outside the box]

Hi there all, just thought I would chip in with my two cents worth re Bendi or flexible plywood.
I am building a split moulded Catamaran to my own design here in New Zealand and am using "A" bonded flexi plywood for the core with internal stringers and glass on inner and outer just as one would with a foam core.
Attached are a couple of pictures to show the shape achieved also a picture of an Australian Tri built using same method, benefits are it is very fast to work and nice shape can be achieved.
regards to all Craig

[outside the box]

More photo's of Auz Tri build method.