Forming marine ply.

yoda

yoda

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I love my Nav area but the flat seat give little support from sliding off on port tack. I would like to make up a slightly curved seat by forming a ply base into a curve and fitting to a suitably shaped support frame. Has anybody done anything similar and got any tips as I have never tried to achieve a curve of any size on a reasonable thickness ply.

Yoda
 
No problem if you use up to 6mm ply, so laminate two pieces together on a former with shaped beams underneath to get 12mm. The ones you see in production boats are usually hot moulded to shape, but cold moulding as described with epoxy works.
 
Laminating several thin sheets of ply with the packing in the centre clamped to a strong bench would give you a curved seat but the curve will be in one direction only.
 
Tranona said:
No problem if you use up to 6mm ply, so laminate two pieces together on a former with shaped beams underneath to get 12mm. The ones you see in production boats are usually hot moulded to shape, but cold moulding as described with epoxy works.
Click to expand...

True.

The curved coachroof on my Twister is made of two layers of 1/4" ply laminated together. It is very strong.
 
You can cold mould any shape more or less. It all depends of the severity of the curve and the thickness of the material. So a big thick bit of ply will easily form a gentle curve over a long distance. If you want complex compound curves in a small area then you need to laminate up some thin board (ply is fine). You have to cut it into strips and do a bit of fitting as a square sheet will not bend in multiple directions without creasing. All you need is a crude mould and a lot of clamps. Once finished the ply may have a small amount of springback depending on how thick it was and how severe the curves or if it has any permanent mould structure. Think of it like papier mâché.
 
Thanks for the advice, laminating it up seems to be the thing to do which is easy enough. Must admit that laminating hadn't crossed my mind but that's why I asked!

Thanks to all.

Yoda
 
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hi yoda,

I'm just finishing laminating the saloon bulkhead in my centaur, long story short if the curve is shallow say a chord of 60mm over the seats width use bendyply, for tighter radius (my bulkhead has a 200mm radius as its break-fronted one side) get some 1.5mm ply and laminate up multiple pieces. From what you've asked though bendy ply will do the job although i ended up nailing it to the former to hold its shape whilst the epoxy kicked, not that bendy after all!

See the fun i've had forming shapes with the stuff http://www.agentlemansyacht.com/search?updated-max=2014-06-03T23:12:00+01:00&max-results=7:
 
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I know its a bit of lateral thinking but if you look up SKATEBOARD DECK construction you will find out how to make curvy plywood shapes :cool:
 
This was what i was on about:

WP_003497.jpg


...............and how i did it

Roger
 
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