Hi Pedro,

I don't know what the paddle makers use but I have used this Klegecell in 20 lb density for rudder fins and helmet mold plugs.

You may want to poke around this site a bit for some answers.

http://www.diabgroup.com/aao/a_products/a_prods_3.html

I have also laminated thin balsa sheets between carbon fiber and that works only if stiffened sufficiently. Any flex will equal crushed balsa and failure. Worked for a Wing paddle but not for a backrest structure.

Best,

Reg

: Does anyone know what kind of foam is used inside of foam-cored paddle
: blades? I built a couple of them with some polystyrene that I got from a
: surfboard shaper, but I'm not convinced it's the best type of foam to use
: for paddles. I also have some polyisocyanurate. It's stiffer than the
: polystyrene, but I'm not sure how well it'll bond with glue or epoxy.

: Thanks in advance for any insight.

: Pedro Almeida