A cast concrete column is one of the molded concrete items that have become popular as a landscaping and architectural detail in recent years. Cast concrete items are not limited to columns, but also include concrete bricks, cobblestones, and concrete figurines.
Making a cast concrete column is a relatively easy and simple process if you have all of the materials needed for the project.
Step 1 – Apply Release Agent
Using either a prepared concrete release agent or spray-on vegetable oil, apply a thin coat to the inside of the concrete mold. Do NOT use diesel oil fuel or motor oil as a release agent for concrete molds. This was a popular method that was used in the past but has been deemed environmentally unfriendly and is discouraged. This will ensure that your mold easily and freely releases the concrete when it is dry. Carefully wipe away any excess release agent so that you will not have any bubbles on the surface of the of your concrete cast columns.
Step 2 – Mix Concrete
Following the instructions on the concrete mix package, mix the concrete. You can also add a colorant to the concrete mixture to create colored concrete columns. The mixed concrete should be stiff and not have excess water as it will not hold its shape in the mold if it has too much water.
Step 3 – Pour Concrete
Pour the concrete into the mold. As you pour the concrete, occasionally tap the mold to bring up air bubbles and pockets to the top of the mold. This will also bring excess water in the concrete mixture up to the top of the mold. Fill the mold to the top with concrete.
Step 4 – Cure the Concrete
Set aside the mold for a minimum of 24 hours to let the concrete cure and dry. Cover the mold with plastic wrap and set it on a level surface in a shady area.
Step 5 – Release the Mold
With the concrete completely dry, turn it so that the fill-hole is at the bottom. Carefully pull the sides of the mold apart to release the concrete. If the sides of the mold stick, push against the center of the mold and then grasp the corners of the mold and pull to loosen.
Step 6 – Additional Cure Time and Sealing
If you are planning on sealing your molded concrete columns, you will need to set them aside in a protected location for a minimum of one to two weeks longer. Covering the columns with plastic will also protect the concrete from damage.
Once the concrete is completely cured, remove it from the plastic wrap and spray the concrete sealant on the column. Carefully apply at least two layers of the sealant, letting each coat completely dry before applying the next layer.
Molded concrete figures and columns are very easy to make with the right materials and concrete casting molds.