I had an unscheduled landing with my Lucky Star 20 trainer causing the the wing to separate where the halves were joined (I knew I shouldn't have used 5-minute epoxy!). The problem is that the plywood brace that joins the wing was broken flush with each wing half and can not be removed. How can I now rejoin the wing halves with adequate strength?

id use a a roto zip bit in a dremel tool and remove all the broken brace I could then clean up the spars with a balsa stick with sandpaper glued on it ,cut a new brace out of ply and rejoin

CAREFULLY cut each rib just in back of the ply brace. What you want to do is have a slot in each rib.

Measure the height of the opening.

Block the wing up so that the 2 halves line up at the proper angle and cut a cardboard template to fit the angle.

Then take some 1/8" ply and trace the angle on the ply. Measure down the height of the opening and trace the angle again.

Now insert a piece of scrap wood into the opening until it butts up against the next rib and mark the distance.

Transfer this distance to the plywood and cut your new brace.

Trial fit the new brace and sand as needed until the brace goes in the openings you cut and both halves of the wing line up properly.

THEN epoxy ONE SIDE of the brace in place making sure it contacts the old ply brace (don't be afraid to use a good amount of epoxy and DO NOT USE A POLYURETHANE GLUE - Gorilla glue etc). When dry repeat for the other side.