You need to get down to the old glass, or wood if the glass is gone. Epoxy stuck to paint will not hold anythiing together.
Sand the area until you have old epoxy exposed all around the repair area with that area showing old glass or bare wood. Then lay down new glass extending out onto the old epoxy. Wet it out and fill the weave like new construction and then sand to smooth it out and to feather into the old epoxy. Repaint to cover the sins.