Thanks - I did not think about precoating the foam. I was thinking of using the foam as the pressure device of sorts to push wetted carbon cloth against the wood stringer in the center. Precoating might give some benefit here too, though I am not sure if I would actually prefer to have more flex in the foam at this step to conform to the slightly rough shape of one of my boards better. Excess epoxy would squirt at the edges and I will achieve the effect of vaccum bagging without a bag for that step in the process and what's needed will remain to fill small gaps/pores in the foam - so not sure if precoating would be better or worse for this step...

It seems it will probably be a good idea to pre-coat the foam on the outside after shaping it and before I layup the carbon sleeve as the outer shell. That I think will fill micro pores in the foam and give a better foundation for the sleeve layup to adhere to.

: Epoxy is a pretty good gap filler, better by far when thickened.
: Wood flour is often use for thickening but it's very fine, finer
: than that from the table saw. I prefer microfibers, basically
: ground up fiberglass as it's considerably stronger. I'd use
: epoxy and pre-coat the foam first, wood too while you're at it,
: then once it's initially cured bond the two together. It's
: tricky bonding to foam that has little strength, it wants to
: dent and create air pockets with little strength between it and
: the wood, precoated it's bonding surface is considerably
: stronger. Don't wait long after the initial cure to bond the two
: or you'd have to sand the pieces, next day is fine.

: Bill H.