Bending plywood ?

[DAKA]

I have a seat that has a curved back and feel its time to replace it.
Its in the cockpit so gets wet occasionally with rain, wash down and sea spray/waves.

the current plywood is bent 90 degrees.

My options

1) fibreglass the old board to strengthen (its not in good condition)

2) bend a bit of marine ply at home with a steamer ??????? no idea how this works)

3) use a 5 mm plastic board but not sure how the upholster could fasten the new vinyl to it

 

[DAKA]

 

[essexboy]

You can buy "Bendy Ply" (Honest)

 

[SC500]

If limited ability and access to a steam source, the best way would be to fabricate a curved board using several layers of thin ply. Make a former of the required shape using the existing back if possible, If the back board is 9mm thick use 3 layers of 3mm ply. Thin ply is flexible and can be bent by hand. Make up a flat sheet of the required overall size using 3 x 3mm sheets of ply with glue in between. While glue is still wet pull the assembled sheets around former and clamp. The sheets will slide over each other to the shape. When the adhesive has cured you have a formed sheet you can then cut to the required shape.

 

[LittleShip]

You could use the original piece as a former and using thinner ply glue and clamp to it. I would use epoxy as a glue and then a thinner epoxy to seal the ply to stop deterioration in the future.

I have suggested this in the past as it's what I now use on Little Ship.

http://www.mbfg.co.uk/epoxy-resins/eposeal-300-epoxy-primer.html

Tom.

 

[vas]

+what the previous posters said

Remove the lining and check it/post photos of the bare ply.
CPES works wonders, could possibly even save the original piece of ply!

Steam is probably a bit too much, if you can get hold of 3-4mm ply you can do it but you need a decent form to keep the ply in shape, wont be easy, I'd try to avoid it.

cheers

V.

 

[npf1]

Or layer up and bond, on a curve, several thin bits of ply.

 

[jimmy_the_builder]

It's hard to get a sense of scale from the photo, but I've found it hard to get a tight radius curve in any normal grade of ply. I'd use bendy ply as suggested above - but I'd use several layers laminated together (as separately suggested above) - ie bendy ply to get the tight radius, lamination to hold the shape. Use the old piece as a former.

Cheers
Jimmy

 

[DAKA]

Thanks for everyones help on this.
I am calling to see the upholster this afternoon and now have a much better idea of direction to take.
I will show him the complete seat before repairing old backing.

I intend to epoxy repair (CPES if I can find some) current ply and then fill old fixing screw holes before epoxy glue thin laminate ply top and bottom .

 

[Vitesse]

Would the original seat do as the basis for moulding a GRP replica?

I think the ply option is probably best, but would GRP be strong enough in a similar thickness? It'd certainly get around the problem of a repeat in a few years.

 

[LittleShip]

I intend to epoxy repair (CPES if I can find some)

You wont find CPES Clear Penetrating Epoxy Sealant

The web site I posted is the same under a different name CPES is used in the USA.

Tom

PS if you do find CPES in the UK let me know.