replacement for Balsa in Spar cores

[Florrain]

Hello,

As we come close to finishing our first F3B molds, we start thinking about layups and materials.

The traditional way the spars are build for this kind of ship is a vertical grain balsa core sandwiched between two UD carbon spar caps.

As selected balsa is not so easy to find and not found in convenient sizes (vertical grain) we are looking for some alternatives like PVC foams or anything else that would be suitable and in the same weight range as balsa.

Any ideas? Any good or bad experience?
Thanks,

Francois

[nuevo]

Can you purchase 6mm balsa sheets and cut your own sheer webs?

[Florrain]

Sure I can do that but that's what I'd like to avoid.

The reason is I have to carefully select the balsa which really is to be done by hand and the shops in the vicinity don't really carry good balsa.
The selection has to be done regarding fiber direction resistence and weight.

Therefore I'm interested in finding a substitude that would have constant density and would be available in higher thickness.

At the root, the spar is +-4.5cm wide wich means I have to glue a few 6mm balsa sheets together which I would like aswell to avoid.

[nuevo]

How about Rohacell then? Assuming you can get the compressive strength you desire.