Clam Chowder with sauce

2 large russet potatoes , peeled and cut into ½ inch pieces (or 1 1/2 lbs.) 1/2 cup butter 3 celery ribs , chopped 1 medium onion , chopped 2 teaspoons minced[...]

4 slices bacon , chopped 3 (6 1/2 ounce) cans whole shelled clams 3 tablespoons butter or 3 tablespoons margarine 1/2 cup chopped celery 1/2 cup chopped onion[...]