The third ballast box is filled. This is one of the two forward boxes to fit fore or aft of floor 3.
As the lead cools down, it shrinks a bit and leaves a small gap ( ~2 mm) all around. I poured a batch of 180 grams of runny epoxy on top to fill these gaps and to cover the surface of the lead. The two boxes that have been ‘treated’ with epoxy fit into the compartments fore or aft of floor 5.