Making concrete or cement blocks from hand molds is the simple way to get started in the concrete block business. Now you can buy cement block molds from dealers on the internet, or for a lot less money you can make your own. The molds you can buy will generally be plastic or cast metal and are not cheap. Molds made from plywood and sheet metal are quite easy to build yourself, and cost much less. They are also a lot easier to repair or replace as they wear out. To make a reasonable quantity of blocks at a time you will need a few dozen molds so you can save a lot of money by making them.
If you need to make concrete blocks in far larger quantities you will need a concrete block machine. Again you can buy an expensive commercial machine which will do an excellent job for you. It will turn out enough blocks to pay for itself in time and makes the manufacturing process fairly easy. The alternative is to build your own concrete block machine. You can build a very good machine from used auto parts which will cost a fraction of the price of a commercially made machine. It will do the job just as well and you can build several for less than the cost of one purchased machine.
You can buy ready mixed concrete in cinder block save money by mixing your own. Concrete is composed of sand, gravel and water mixed in the right proportions with Portland cement. Depending on the job to be done the proportions of the various components in the mix will vary. Concrete does not just dry and harden. There is actually a chemical reaction between the cement and water which causes it to harden into a crystalline mass which binds the other components together. If there is too little cement the concrete will be weak and if too much water is used it will not be good either. You need to measure the various components accurately before mixing them.
You can mix the concrete by hand on a cinder blocks or plywood sheet. Do not mix it on the ground where contamination by extraneous material will result in weaker concrete. For modest amounts of concrete hand mixing is appropriate but if you are in production and need large quantities to manufacture concrete blocks or other products it is necessary to have a cement mixer or mixers to do the job. A mixer also ensures that the concrete is thoroughly mixed and even throughout.
A concrete block making machine or machines will enable you to turn out hundreds or even thousands of cement blocks daily. If you are in business to supply builders or other buyers in quantity you will require machines to produce enough blocks to fill large orders. Building a machine yourself is a great way to get a low cost start when you want to move up from making blocks from hand molds. Later you may want to acquire a high production commercial machine but that is unnecessary till you need a lot more production.