Get your containers ready . Decide how many candles you will be making , and then prepare your tubs or containers by spraying with a non-stick cooking spray . Make your concrete mix , using cement , sand and water . We ’ d recommend 2 parts sand to 1 part cement mixed thoroughly , before slowly adding water and mixing well until it is a batter-like consistency . Add some cement to the base of each container – around a third should work perfectly . Then firmly tap the container against the work surface to remove any air bubbles . You can also tip your container slightly to one side and let it rest against something to create an uneven cement base for visual effect . Leave the cement to dry for at least 24 hours . Once your cement has set , melt enough wax using the double boiler method to fill your containers . Stir the wax with a wooden paint stirrer , chop stick or pencil .