Any outdoor project that requires landscaping and concrete block work will cost much less if you do the work yourself including the molding of the concrete blocks. Sure you can buy concrete blocks at the store but building them yourself will save you money in the end. To build these cement bricks however you need to make a concrete block mold and give the project enough time to make your blocks and cure them. This guide should give you the basics you will need to mold concrete blocks yourself to save money.
Make your basic concrete block molds out of 2 X 4s to allow for strength in the mold and the ability to take the mold apart and reassemble many times over. When you mold concrete blocks for any project you will need many blocks and at least a day for each block sitting in a mold. If for instance you need to lay 300 concrete bricks then you will need to mold ten bricks a day for a month or thirty bricks a day for ten days. Calculate how many bricks you will need at your given dimension and calculate how many molds you need to make. Standard US dimensions for concrete bricks is 8" x 4" x 2.25". Remember that each cement brick will sit in the mold for a day and then cure.
Mix your concrete in a container at a ratio of one part cement, two parts sand, and three parts gravel. Make sure you mix exactly what you intend on molding as you do not want extra concrete leftover. Add water to the container and stir to make the final concrete mixture. If you have access to a small cement mixer this will be your tool of choice as the mixing process will be easier.
Pour or scoop your cement brick mixture into your molds. To better mold concrete blocks make sure you shake the mold to let the cement mixture fully settle into the corners of your cement brick mold. You can also pick the mold up a few inches from the ground and let it drop to use gravity to help settle the cement mixture better.
Once you have filed your concrete block mold with your cement mixture you will want to level off the top of your mold with a straight edge. Use a piece of lumber or an extra 2 x 4 to scrape the excess cement of the top of your concrete block mold and allow for a flat surface to form as the concrete block dries.
Your molded concrete blocks need to remain in the mold for a day before they are sufficiently hardened. At the end of the 24 hour period you can disassemble your concrete block mold and set aside the newly formed concrete blocks to further cure before use.
If more bricks are needed then repeat steps one through five each day until you have molded enough concrete blocks to satisfy the needs of your project.