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This Instructable will demonstrate how to make a concrete iPad stand from a plastic popcorn bucket, it's inspired by a project from the Easy Concrete Projects book. No previous experience working with concrete is necessary, but you should be comfortable cutting thin plastic with a hand saw, shaping styrofoam, mixing and pouring concrete, cutting away the plastic form, sanding the base, and making the shelf that supports the device from wood or tile.

Time Required: 1-2 hours + 2 days to cure

Weight: 4-6 pounds

Materials:
Plastic Popcorn Form ($1 section at Target)
Sacked Concrete Mix  - NON-Aerated, 5000 psi is ideal (one 60lb bag will produce about 12 of these forms)
CHENG Pro-Formula Mix (1 cubic foot box per two 60lb bags)
CHENG Sealer
CHENG Wax
Styrofoam (small scrap pieces)
Wood (.5" thick)
2 Part Epoxy

Tools:
Ruler
Permanent Marker
Clear Packing Tape
Hand Saw (Japanese style with fine / medium teeth)
Razor Blade / Utility Knife
Sand Paper / Handheld Diamond Polishing Pad
Slotted Screw Driver / Phillips Screw Driver
1/16" drill bit
Silicone (100% silicone, window and door sealant)
Rubber Gloves
Safety Glasses
Buckets for Mixing
Plastic Scraper

Step 1: Measure, Mark + Cut the Concrete Form

1.1 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.

1.2 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.

1.3 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.

1.4 Clean up the edges of the plastic with some rough sand paper ( 80-100 grit ) and be careful not to scratch the inside of the form (any scratches WILL be transferred to the concrete).

Step 2: Make, Tape, Silicone + Install the Concrete Knockout

A knockout is a piece of foam, rubber, plastic, felt etc. that is secured inside the form in order to create a void, recess, or opening in the concrete. For this piece we'll use a small knockout to create a recess for the "shelf" to slide into. This recess only needs to be about ¼" thick if you're going to glue the shelf in place. We can make a knockout from scrap styrofoam, or we can use thick felt with an adhesive backing (for furniture to keep it from scratching the floor).

Styrofoam Knockout:
2.1 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).

2.2 Wrap the styrofoam neatly with clear packing tape. This will keep it from bonding to the concrete and will give us a smooth surface.

2.3 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.

2.4 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).

2.5 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.

Adhesive Backed Felt Knockout:
2.1b Find some heavy duty felt with an adhesive back, cut down to the size of the knockout, stack two or three pieces together.

2.2b Wrap the stack of felt pieces in clear tape, peel off adhesive backing and fix to the inside of the form. The advantage of this method is that you don't have to wait for the silicone to dry. The disadvantage is finding and paying for the felt!

Step 3: Mix, Pour, Vibrate, Cover + Cure the Concrete

For tips on mixing concrete, check out the How-To-Mix Concrete Instructable.

Weighing out dry materials should be done somewhere with proper ventilation and it's a good idea to wear a particle mask if you're doing it often. Small projects like this can be mixed by hand. It's best to wear rubber gloves and work in a space that is easy to clean up. It's also a good habit to start with clean tools, buckets, and especially a clean workspace so we don't accidentally get pieces of dirt or styrofoam in our batch of freshly mixed concrete.

Normal sacked concrete will be cured enough to demold in about 5 days. Smaller projects like this can be taken out of the form after 2 or 3 days.

3.1 Start with a gallon-bucket (or an old mixing bowl). Measure out 1½  popcorn containers (about 6 pounds) of sacked concrete and dump it into the bucket. Add Pro-Formula Concrete Mix (1/24th of 1cu. foot box). Mix thoroughly and break up any big clumps of material. Add about 6 ounces of water to the mix, keep stirring by hand or with a spatula or trowel, always scraping the sides and bottom of the bucket. Gradually add about 6 more ounces of water until the consistency is like runny oatmeal.

THE IDEAL CONCRETE MIX
When mixing concrete, it is important to note that the least amount of water used relative to the cement produces the least amount of shrinkage and yields the strongest, most durable concrete. At the same time, the mix needs to be fluid enough to fill all the gaps in the mold. A mix that is too dry is hard to pour and vibrate; a mix that is too wet is likely to shrink excessively and may crack.

When the concrete is fully mixed, you have about 20 - 30 minutes before it will harden and become unworkable. You can agitate the concrete by squeezing it in your hands to regain some fluidity if it gets too hard.

3.2 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.

3.3 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. Your final piece will always have some air bubbles if you're not using a commercial concrete vibrator. If you aren't getting results you like vibrating by hand, you can try using an orbital hand sander or a sawzall without the blade and vibrating it against the form walls.

3.4 After the form is vibrated, wedge a piece of ¼" foam under one side of the container so the top surface is level.

3.5 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).

3.6 Move the form carefully to a place where it can cure for up to 2 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 4: De-molding the Concrete Form

De-molding is the when you remove the forming materials from the cured concrete. Sometimes the concrete can be removed without destroying the form, but in this case we're going to break away the plastic bit by bit. Any cuts you make through the plastic will scratch into the concrete, so be careful not to cut, pry, or gouge the concrete in any of the following steps!

4.1 Wearing rubber gloves and safety glasses, prepare to de-mold. Scrape excess concrete off the plastic form with a razor blade.

4.2 Start at the opening of the container, peeling back the plastic by hand and slicing down into it with a sharp razor blade.

4.3 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.

4.4 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.

4.5 After the plastic form has been removed, pry out the knockout with a flat screwdriver.

Step 5: Sand, Grind + Make the Concrete IPad Ledge

5.1 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.

5.2 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. You don't really need power tools for something like this. Check out the episode Sawing Secrets from the Woodwright's Shop on PBS for some tips on working wood with hand tools.

5.3 Finish the concrete with CHENG sealer and CHENG wax before gluing the ledge in place with two-part epoxy.

Step 6: Concrete IPad Stand, Finished Images

Your Concrete iPad Stand is now complete—at CHENG Concrete, we believe design is dynamic, always fluid, which is why we’ve assembled a few other projects made from this humble popcorn container.

We’re sure you’re able to come up with a ton of your own ideas for this nifty container—we’d love to hear from you and see what you’ve created—please send us your version of the Concrete iPad Stand or any other project versions at concretefun@chengconcrete.com. GET IN THE MIX, HAVE FUN WITH CONCRETE!

<p>Good evening! </p><p>Can I watch all these courses on dvd tutorial?</p><p>when I do the productions, can I sell them?</p>
<p>Wouldn't this scratch the back of your iPad?</p>
I'm confused - I love the monolithic look of this, but the finished pictures show the top being open for pencils, etc. Would this space be achieved like the knockout for the stand? Attaching a piece of coated wood or Styrofoam to the bottom of the 'popcorn cup' mold and securing with a screw? How thick can the upper edges be? Will the upper thinner edges be at a different cure rate than the solid bottom? Also, different aspect:any luck with coating molds with vaseline? Would it make swirly texture, allow for mold release and possibly seal concrete? I suppose it could be scrubbed off with detergent...
You're exactly right about the top being open. This was accomplished by pre-drilling a hole in the bottom of the popcorn form and then screwing a rectangular foam block in there. Taping the foam will keep the residue off of the concrete. Some silicone under the foam will help it stay in place and keep concrete from getting underneath it (and forcing it up), but a long screw (2&quot;) should work just fine. If you don't pre-drill the plastic, it will probably crack and split. <br>There are no issues with it curing at different rates depending on the thickness, but covering it with plastic while it cures is a good idea because it keeps the humidity inside. I'd recommend light vegetable oil as a form release instead of vaseline because it will be easier to apply with a brush or paper towel. You really only need a very thin layer.
How would you get the air bubbles out so you didn't have all the holes? Some type of shaking device?
Any vibration is better than nothing. For a small form like this, just tapping on the sides, shaking it around, and dropping it lightly down on the tabletop will work.<br> <br> You can also use a palm sander and touch it to the sides of the form. For stronger forms you can try thumping it with a sawzall (without the blade).<br> <br> Check out this instructable: <a href="https://www.instructables.com/id/DIY-Concrete-Vibrator-for-Small-Forms/" rel="nofollow">https://www.instructables.com/id/DIY-Concrete-Vibrator-for-Small-Forms/</a><br> <br> For larger projects in the shop we'll use table mounted vibrators, like the <a href="http://store.concreteexchange.com/CHENG-Concrete-Online-Store_5/Vibration-Compaction_4/Vibco-Table-Vibrator-Mounting-Plate" rel="nofollow">Vibco US450T</a> seen below. These are overkill for small projects, but they work very well.<br> <br> You'll never get all the air bubbles out, but you can always fill the holes in later with <a href="http://store.concreteexchange.com/CHENG-Concrete-Online-Store_5/Finishing-Material-Supplies/CHENG-Pro-Formula-Acrylic-Slurry" rel="nofollow">slurry</a> (cement and pigment mixed with water to a toothpaste consistency).
very clear and complete explanation. and certainly this support not goes with the wind.
very clear and complete explanation. and certainly this support not goes with the wind.
Simple and elegant... I must do this one.
Cool project, I'm going to have to try it! I just ordered the Cheng countertop book. I can't wait for it to get here!
The form I got had reinforcing ribs in the corners that caused a bit of tear out, but over-all quite pleased. I had been doing some wiring and simplified the process by casting the wire self in the concrete.
WOW Nice work on that wire shelf! <br> <br>Did you just drill two holes in the form and tape the wire in place? <br> <br>
I drilled small holes in the form that were tight enough to need to force the wire through and used a block of Styrofoam to hold the wire in place with the desired spacing. I also bent the wire a bit inside the form for additional security that I doubt is needed, but it is not pulling out without destroying the concrete. <br> <br>After making a few I tried marking the fill lines on the inside of the form and skipping the cutting of the plastic down. This is not quite as smooth on the base, but a little work with a flat file just after demoldling worked easily and was faster, for me, than sawing the plastic. <br> <br>Thanks for noticing, I love your work. <br> <br>
That should be shelf...
Love your design! To cushion the back, I'd suggest using clear or nearly clear silicone bumpers. These are found in home improvement stores in the same area as one would find the felt bumpers used to quiet closing cabinet doors and drawers. Yours is the sort of project that makes me love instructables. <br> <br>Well done!
Nice - though something soft like a bit of felt to cushion the back would work to stop it scratching during use, but would distract from the look you're trying to achieve. Maybe stick felt to the ipad? :)
That is awesome! The glass and grey concrete go so well; especially with the white iPad!
Thanks for the comments!<br><br>The 'stone' Pro-Formula and the green glass look great together, but a wood shelf looks good too, and it's a lot easier to cut if you don't have a tile saw!<br><br>Here's a version with the shelf made from beech wood holding a samsung galaxy tablet. All the best,
Very, very nice!

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