Combine sugar and water in a bowl and stir to dissolve sugar.
Slice ham just shy of the bone into 1/2- to 1-inch slices. Place ham into the water and sugar solution; add more water, so ham is completely covered with liquid. Seal with plastic wrap and let soak in the refrigerator for a minimum of 48 hours.
Preheat the oven to 250 degrees F (120 degrees C).
Combine honey and orange juice in a bowl. Line a roasting pan with aluminum foil.
Drain the ham slices, pat dry, and place in the roasting pan. Wrap aluminum foil around the bottom of the ham and pour 1/2 the orange juice mixture over the ham. Wrap ham completely in foil.
Bake in the preheated oven, basting with the remaining orange juice mixture, until a sticky, browned glaze forms, 3 to 4 hours.