: I'm getting close to the point where I have to get the hull fair for glassing
: and I'm looking at the stems where the plywood panels have been joined
: 'side to side' creating an 8 mm wide flat surface at the very ends. I
: suppose I could just round it off with a sander but that would expose the
: interior plys and I'm not sure I could make it even. I'm a little leery of
: trying to run a bead of thickened epoxy down the ends and blend it into
: the bottom without making a serious mess.

: Any advice here? Is there any kind of a jig or form to shape a bead of epoxy
: so it's even and fair? The part that has me stumped is the changing shape
: as the panels go from 'side to side' to 'end to end'.

From a pure utility standpoint, there is no problem exposing the inner plies. The fiberglass will protect everything. From an appearance standpoint, a neat job of rounding the plywood will make the inner plies form nice straight lines and it will look fine. This is by-far the easiest thing to do. The best looking would probably be laminating on a stem as Ross suggested. While not really hard, this is the most difficult. Cleaning up squeeze out and making a smooth transition without messing up the plywood may be a little tricky.

Building up a bead may be a happy medium, but I don't see any benefit to this method. It isn't particularly pretty, easy or stronger. I would either add or subtract wood and not bring schmutz into it.