How to make a concrete seat

 Part 4. Casting the concrete

Steps 4.1 to 4.3   Applying the release agent, half filling the seat form and placing the reinforcing

Lay all the form pieces out on a flat work surface.

Step 4.1   Applying the release agent

Apply ample *release agent to all the form pieces on all sides with a paint brush.
Wipe off any excess with a rag.

*Note:   A release agent is a substance that is applied to surfaces to prevent them from sticking, in this case so that the concrete does not stick to the form. You can purchase form release agents from some building supply stores, often in handy little spray bottles. You can also make your own for a fraction of the cost out of an even mixture of used car oil and diesel, and apply it with a paintbrush or a rag. That’s what we do.

Step 4.2   Half filling the seat form

Pack the seat form an inch or two up off the work surface so that you are able to get a hand under the ends. This is so you can lift an end up slightly and drop it multiple times in quick succession to vibrate and settle the concrete to help eliminate air pockets and make a smooth surface.

A little under half-fill the seat form with concrete and vibrate the form to settle the concrete. Do this by tamping and poking the concrete with a broad thin stick, say ⅛” (3mm) thick x 1½” (38mm) wide, also by using the rapid drop method as mentioned above, and also by tapping around the edge of the form with a hammer. The more vibrating the better.

Step 4.3   Placing the reinforcing