: If you were to sheath the stem in plastic wrap or masking tape to
: prevent the strip from being epoxied to them, couldn't you just
: pop them out when the outside of the boat is glassed - just like
: you do with the forms?

Might work though if you catch the masking tape when planing down the cutwater you'll end up glueing the outer stem to the inner. Not much flex in the narrow ends of the hull so unlikely to 'pop' out. You may have to get medieval.

: I'm using some WRC for my inner stems and they are pretty light as
: well but I'm always looking at different ways of doing things.

Using WRC it would be easier than MDF to gouge out the stem if it does get stuck. Being a soft wood be careful not to pull the stem over to one side while planking. Mine has a bit of a kink to starboard!
(looked at photos, 2 years today since I epoxied the outside of the hull. It is now scratched, I must make another kayak! :¬) )

. . . Ben