iPad Easel

Step 2 – Measure, Mark, and Cut Popcorn Form

• Mark two adjacent corners at 7½” and the other two at 6¾”. Draw four lines connecting the dots with the permanent marker. This is the cut line.
• To help support the plastic container while cutting, cut a styrofoam block (about 3¾” x 3¾”) and push it in the opening of the form.
• Starting from one corner, gently saw back and forth to start a straight cut. Go slowly at first, alternating back and forth between corners until you can connect the slices and cut through. Repeat on the remaining sides until the cut is complete.
• Clean up the edges of the plastic with some rough sandpaper (80-100 grit) and be careful not to scratch the inside of the form (any scratches WILL be transferred to the concrete).

Step 3 – Make, Tape, Silicone, and Install the Knockout

• Rough cut a small piece of styrofoam with a saw or utility knife into a rectangle and sand down to 1½” wide x ½” tall x ¼” – ½” deep.
• Wrap the styrofoam neatly with clear packing tape. This will keep it from bonding to the concrete and will give us a smooth surface.
• It might be helpful to make a small cardboard template to use as a guide to center the knockout in the form. Apply a thin coat of silicone to one of the ½” faces and press it down into the form. Wipe away any excess silicone that squeezes out and wait a few hours for it to cure.

Step 4 – Secure the Knockout

• Drill or cut a small hole (1/16″) behind the knockout and install a short 1″ screw so the knockout doesn’t float away during the pour. (The silicone is going to keep concrete from seeping between the knockout and the form wall. If that happens, the knockout will move around and could be lost completely).
• The silicone is also keeping the foam from floating to the surface — foam floats in water, and concrete contains water. The screw will hold the foam just in case the silicone does not.
• After the silicone has completely cured (at least 3-6 hours and up to 24), remove the excess with denatured alcohol and blow any debris out of the form.

Step 5 – Mix, Pour, Vibrate

• Pour concrete into the form, but be careful not to dislodge the knockout. While pouring, smear concrete around the inside walls of the form and under the knockout to coat the surface with concrete. This will help minimize trapped air.
• To help the air bubbles rise to the surface, vibrate the concrete by tapping the base of the form on the tabletop for a few minutes.

Step 6 – Smooth, Cover, and Cure for 4+ Days

• Smooth/trowel the surface with a plastic scraper. Take some time to remove excess concrete from the sides of the container, and get that top surface as smooth as you can (this will minimize sanding later).
• After the form is vibrated, wedge a piece of ¼” foam under one side of the container so the top surface is level.
• Move the form carefully to a place where it can cure for 4 days. Cover with a plastic bag or painter’s plastic. This helps hold the heat and moisture in the concrete so it doesn’t cure too quickly and crack. For this reason, do NOT place the concrete to cure in direct sunlight; keep it indoors or in the shade.

Step 7 – Demold the Concrete

• Start at the opening of the container, peeling back the plastic by hand and slicing down into it with a sharp razor blade.
• Break plastic away by hand or with pliers. Remove a little bit at a time. Peel back, slice, break away. Do this as carefully as possible, still taking care not to scratch or chip the concrete.
• Be very careful when removing the bottom of the container. On each side of the form there is a tab. A small screwdriver or chisel and a quick tap from a hammer will help free those tabs.

Step 8 – Remove Knockout and Sand Edges

• After the plastic form has been removed, pry out the knockout with a flat screwdriver.
• Flatten the base by sanding the bottom surface with a rough 120-grit hand-held diamond polishing pad. Alternately, use a belt sander and ideally a 5″ wet polisher with diamond pads suitable for concrete.

Step 9 – Make the Wood Ledge

• Using a hand saw, band saw, or tile saw, cut a ledge that fits in the groove created by the knockout. The easiest thing to do would be to start with a piece of wood that is the same thickness as the knockout (½” in this example). Softer woods will be easier to cut with hand tools if you don’t have access to a band saw.
• Finish the concrete with CHENG Sealer and CHENG Wax before gluing the ledge in place with two-part epoxy.

Step 10 – Glass Ledge

• If you have a tile saw, you can make the ledge out of glass, following the same steps in the previous step.