Concrete moulds can transform the texture and shape of concrete regardless of the amount of concrete you're working with. Making a concrete mould can be as simple as repurposing a foil tin to shape a basic concrete stone or forming your own mould from sheets of polyurethane. If you plan to pour your own concrete pavers, make multiple moulds so you can pour them in batches.
Decide on the size and shape that you want the poured concrete blocks to be. Mark a cut line with a pencil over four pieces of 1/2-inch timber equal in width to the thickness of the intended concrete paver. Two boards should be marked for the length of the block and two for the width.
Use a circular saw to cut the four boards in to two equal length pieces and two equal width pieces. For instance, for a 6-by-7 inch paver, you should have two 6-inch boards and two 8-inch boards.
Arrange the four boards in a rectangle with the 6-inch boards sandwiched between the 8-inch boards on either side. Place a strip of masking tape over each corner to hold the boards together.
Use a drill to make two pilot holes on each side of the 8-inch boards one-quarter of an inch from each end so both 8-inch boards will have four holes each. Secure eight 1/4-inch screws into the holes with the screwdriver.
Apply mould release agent over the interior of the mould with a sponge.
Spread an inch of sand over a level surface large enough to accommodate all of your moulds.
Mix concrete with mix and water in a bucket until it is stiff. If the mix is too thin your concrete blocks will be weak.
Fill the mould with concrete, using a trowel to push spread it into the corners. Tamp the surface with the flat side of the trowel and run it over the top of the mould to remove excess. Make the top of the concrete smooth by running the edge of the trowel evenly over the surface. Allow the concrete to set for about two days, then lift the mould from the concrete.