Ever look at a tennis ball and think, "Man, you'd be much more useful if you were concrete?" Me, too. One way I've found is to make a phone stand using a tennis ball and some cardboard as a mold.
Teachers! Did you use this instructable in your classroom?
Add a Teacher Note to share how you incorporated it into your lesson.
Step 1: Materials and Tools
Cheng Shapecrete Concrete
At least one glove
One tennis ball
Non-Stick cooking spray or other release agent
A glue stick (White school glue works as well)
A knife or similar
Plastic Wrap (Not Pictured)
One sheet of craft foam (Also not pictured)
Sanding screen (No, not pictured, either)
Step 2: Cut Up Some Cardboard
Cut several strips of cardboard. Ensure that each strip is longer than the tennis ball is wide. Also keep each strip a couple inches tall.
Stack your pieces of cardboard next to your phone. The goal here is for the cardboard to be thicker than your phone. The cardboard will help create the seat for your phone to sit in. We will be adding some cushion to this seat later, so make sure the cardboard is thicker than your phone when stacked. The stack in the photo is too close to the thickness of the phone. One more piece of cardboard should be added in that photo.
When you are satisfied with the amount of cardboard you have, glue it all together.
Step 3: Cut Up Your Tennis Ball
Cut a slice off what will become the bottom of your tennis ball. I've included the materials photo again because it shows how much I took off. It's about 1/4 to 3/8 inch thick.Just enough so it's stable sitting on the table. Make this cut as straight as you can as everything else after this is based on this cut.
Using your cardboard stack as a guide, mark where your seat will be on the tennis ball. Ideally there will be some angle to this cut, so your phone will lean back a bit when placed into the holder.
Don't place the seat too far forward!
I've made this mistake myself. Tennis balls are thicker than I had anticipated. Putting the seat too far forward will leave no room for the concrete that follows later. Placing the seat just forward of center worked well for me.
Cut where you marked and check the opening with your stack of cardboard. It should be good and snug, but without having to force the cardboard in. Another thing to watch out for is keeping the seat parallel to the bottom you just cut. Make sure your cuts are even, else your phone will rock or sit unevenly in it's stand.
When done, wrap your cardboard stack in plastic wrap and place into
Step 4: Mix and Stuff Your Concrete
Now it's time for concrete. Mix your concrete to a somewhat stiff consistency. This mold is not seaeld in anyway, and a watery mix would ooze out. When you're ready spray the inside of the tennis ball with your non-stick cooking spray.
Take a small bit of concrete and fill the small area ahead of your cardboard first. This will probably be the hardest spot for the concrete to get into being as it's a bit thick. After that fill the rest of the ball and level off at the base. Try to keep the base as flat as possible to avoid an unsteady stand later.
Check for any concrete that got pushed out around the cardboard stack. Cleaning this up now will save a lot of work later. Set the tennis ball on its base somewhere to dry.
Step 5: Free Your Stand and the Rest Will Follow
You've waited long enough, let get that thing out of there.
Make some cuts to the tennis ball from the base toward the middle of the ball. Making a few cuts here should allow the stand to just slip out of the tennis ball. As you can see, there will be a lot of flash. Don't panic. Most of it will come off with just your fingers.
Using a sanding screen here helps. The concrete dust created my sanding just falls through the screen, making for an easier time all around. Give the base a good sanding. Lay the screen on something flat and move the stand on it in circles. It won't take off a ton of material, but will help insure the base is flat.
Use the screen on any rough edges around the seat as well. Wrap the screen around the cardboard stack, and place into the seat. This will be a tight fit, but will help improve the overall fit and finish.
Step 6: Protect Your Phone and Tables
No one likes a scratched up phone, or table. So let's put that craft foam to use.
Cut a disc sized to your base and glue it on. Rubber cement may be a good choice here, but I used what I had. The glue stick has worked fine so far.
Next come the seat. Cut a strip to fit the width of the bottom. The place into the seat and trim to size. I didn't bother gluing this piece as the next pieces will hold it in place. If you'd like to glue yours, go ahead. Then do the same for the front and back of the seat. You should now have a nice cushy seat for your phone.
Step 7: You Put Your Phone in There
That's it! Put your phone in it's sturdy new stand and relax.
Participated in the
Concrete and Casting Contest