I fiberglassed the external ballast after the hull was sandblasted.

I used epoxy and several layers of fiberglass to cover the seam and part of the ballast.  Generally, I did not glass around the bottom of the ballast because I thought that I would only damage the glass if I should ever run aground.  The fiberglass now runs down to about 6" above the bottom of the ballast.  I did fiberglass around the bottom of the ballast where it meets the false keel.

I think the epoxy did a good job of adhering to the lead ballast because it was clear of paint and severely pitted by the sandblasting.