Prepare the bottles: Wash the bottles, remove labels and allow them to dry completely. Plan your design: Arrange the bottles in a circle to test the sunburst pattern. Prepare the mould: Coat the round mould with release agent and place a small round insert in the centre. Mix the concrete: Mix PPC Cement, fine building sand and clean water to a thick, workable consistency. Pour the base layer: Add concrete to the mould and spread it evenly with a trowel. Add the bottles: Press the bottles into the wet concrete, with the necks facing the centre.