The Stinger and my Proud Bird have balsa wing tips.

The following is how you add some strength so they don't break so easily. Wood for both the Stinger and Proud Bird are prepared here:

Begin by cutting pieces of 3/8" light balsa.

Between the balsa sheets there will be a piece of 4 ounce glass cloth.

Squeegee some epoxy on the balsa and the glass cloth. Then lay the parts together.

The parts were put in a homemade vacuum bag and the air was removed (6" of Hg).

The result will be a balsa-fiberglass-balsa laminate that will be much stronger than a single layer of balsa.