- Atlas stones are man-made concrete boulders used to prove human strength in strongman competitions.
- Cover a large rubber ball with plaster of Paris, using the plywood square as a work surface.
Once the plaster mould has dried overnight, deflate the rubber ball inside the mould by poking it with a knife, or using an inflation needle if you wish to reuse the ball for another stone. Remove the ball from the inside of the mould.
- Once the plaster mould has dried overnight, deflate the rubber ball inside the mould by poking it with a knife, or using an inflation needle if you wish to reuse the ball for another stone.
Mix four bags of Portland cement in a mixing trough. Slowly add water and completely mix with a shovel until the concrete becomes the consistency of thick pancake batter. Remove all lumps in the wet cement so that there will be no imperfections in your finished stone.
Pour the concrete into the plaster mould with a shovel, filling up the entire sphere. Make sure that the concrete is not leaking out of the bottom of the mould. As you pour the concrete into the mould, tap the plywood base with a hammer, which will pop any air bubbles in the concrete (bubbles could cause imperfections in the Atlas stone). Cover the top of the mould with a damp rag to keep the concrete from drying too fast and cracking. Allow the concrete to dry at least three days before removing the mould.
Remove the mould by gently tapping it with a hammer. This tapping will slowly remove the soft, plaster mould from the concrete sphere in the centre.
Inspect the outside of the finished stone for imperfections and patch them with concrete patching compound, where needed.
Complete the project outdoors or in your garage, because it can be very messy to clean up.