Concrete is a versatile material that takes many forms. It sometimes looks like wood, metal or stone. When used as a fence post, it offers strength and durability. Concrete fence posts are made using a form. This form is a simple box that holds the concrete until it dries. If you are ambitious enough, casting concrete is something to try at home. With just a few special compounds the job will yield strong fence posts that will last a very long time.
Build the forms to cast the concrete fence posts. Construct a long wooden box form that is the length, width and depth you wish the fence posts to be. Typically, fence posts are 5 feet long and 5 inches square. Cut four plywood sheets to this length and width, and assemble them with framing screws to form the mould box. Reinforce the corners of the box by installing metal brackets on the outside corners.
Caulk the inside seams of the form with silicone caulking. Smooth the bead with your finger to remove the excess.
Coat the interior of the form with concrete mould release compound by sprinkling it into the form. Then cut a 5 inch square plywood sheet and attach it to one end of the form with framing screws. Coat this with mould release prior to installation.
Mix up your concrete in a wheelbarrow and shovel it into the mould until the mould is full. Set the mould to dry for 12 to 24 hours. The drying time will vary based on atmospheric conditions.
Touch the mould to see if it is dry. When it is completely solid, pry off the mould boards with a crowbar to release the fence post.
Experiment with concrete mixes and mixing ratios to create different types of fence posts.