Set aside two cups (0. 5 liters) of concrete mix. This mix can be added to the concrete if the consistency is too runny. Read the mixing instructions on the bag of concrete to ensure that you have the correct ratio of water to concrete mix.
Concrete that is too runny is easier to pour but less durable and more likely to break over time. Add more water to your concrete mixture if the mixture is solid and crumbly. [3] X Research source
You can apply a small amount of engine oil to the cast before pouring the concrete to ensure that the concrete is removed from the cast easily without damaging the sculpture.
Allow the cement to cure for at least one week before use. Read the instructions that come with the cast. These instructions will give you specific information about when and how to remove the cast. Each project will be different.
Pour the concrete in small, workable sections to prevent the concrete from drying before you finish the sculpting. Concrete that is too runny is easier to pour but less durable and more likely to break over time. Add more water to your concrete mixture if the mixture is solid and crumbly. [9] X Research source The amount of time that you need to wait will depend on the thickness of the concrete mold. The concrete is ready to carve when it is still malleable and holds it’s shape.
Coat your hands in petroleum jelly to prevent the concrete from damaging your skin. Avoid touching the surface of the sculpture until it is completely dry to prevent any smudging. The concrete should be dry within 24 hours but should be left to cure for seven days.
Use a metal mesh that is heavy enough to hold its own shape.
Read the instructions on the bag of concrete before mixing the concrete and water. The instructions will provide clear ratios of water to concrete. Concrete that is too runny is easier to pour but less durable and more likely to break over time. Add more water to your concrete mixture if the mixture is solid and crumbly. [12] X Research source
