Concrete blocks are used to build houses and fences and are always in demand. Here is how you can start your own business by making your own concrete blocks at home.
Concrete blocks are usually produced using a semi-mechanized stationary type machine. These machines run thousands of dollars and allow you to produce a 1000 blocks per day. But if you are just starting out and can't afford a machine yet, you can build your own mold.
Using a concrete block as a template, measure around the outside of the block and cut 2 x 4's to length. You will be making a box. 4 sides and a bottom but no top, as you will be pouring the concrete into the box. The Typical size is 300 x 200 x 150 mm. Use screws to hold the box together instead of nails. When you get the hang of it you will want to build a lot more wooden molds and can produce 100 blocks a day.
The recipe for the concrete block is 1:12-14 in other words 1 part cement : 12-14 parts sum graded aggregates. Aggregate is sand, gravel, crushed stone, slag, and recycled concrete and is used to reinforcement the strength. You will use fine and course aggregate.
Put plastic inside your wooden mold and then pour in the concrete. Wait 24 hours, flip your block out and make another one.