Insert a wood stake into the ground at each corner along the area where you want to install the concrete curbs. Space the stakes 1/4 inch away from the desired edge of the curb. Extend garden string between the stakes to form a guideline.
Mix concrete, aggregate, sand and water in a wheelbarrow until the mix achieves a 0-slump consistency. To test the consistency of the mix, pour it into a Styrofoam cup with its base cut off. Turn the cup face down on a level surface and slowly pull it upward to remove it, leaving the mix on the surface. The mix with a 0-slump consistency will hold its shape. If required, add more water or concrete to the mix to achieve the desired consistency.
Transport the curbing machine to the desired spot. Insert the desired slip form into the curbing machine that helps create the desired shape of the curb. Ensure the slip form rests firmly on the ground and its back is 1/4 inch higher.
Pack shovelfuls of the prepared mix into the curbing machine’s hopper, or the reservoir, meant for collecting the cement, without filling it completely. Start the engine according to the manufacturer’s directions.
Steer the curbing machine along the guideline as it begins to extrude the concrete curb along the desired spot on the ground. Continue to pack shovelfuls of the concrete mix into the hopper, ensuring the hopper does not run out of the mix. Stop filling the hopper when the curbing machine reaches the end of the guideline.
Turn the machine off when the concrete curb is installed. Remove the slip form before thoroughly cleaning it with water. Also clean the hopper and the body of the machine.