Step 7: Commence the concrete
Fix the lower piece of plywood in place, ensure that the reinforcing steel is placed central, and commence making and pouring concrete up to the top of the
seat level as shown in fig.7.
You can make mix your own concrete using cement, sand and gravel. For information about how to mix concrete
Or you can buy bags of cement, gravel and sand already mixed, which only require the addition of
water to make concrete.
As you pour the concrete, vibrate the framework by tapping with a hammer in a continuous motion to settle the wet concrete and get rid of any air bubbles.
Step 8: Add a plywood piece
Screw another piece of plywood in place to cover the freshly poured concrete.
Step 9: Top up the concrete
Screw the final piece of plywood in place and fill the framework up with concrete.
At this stage the framework should be completely filled with concrete and the steel rod should be sticking out the 500mm top (which is really the
bottom because the chair is upside down).
Vibrate, vibrate, vibrate. Ensure that the framework is well held together with screws and clamps, and tap all around the outsides causing vibrations that will settle
the concrete and remove the air bubbles.