How Do I Build a Sphere?

Making a sphere is easier than you might think.

You make a perfect sphere every time you or your child blows a bubble. But with patience and a gentle touch, you can also make something that will last a little longer. Through a simple process that will take just a few days, you can use quick-setting concrete and a plastic, blow-up exercise ball to craft a perfect sphere suitable for placement in your home garden. It's easier than you might think.

Things You'll Need

• Exercise ball
• WD-40, Vaseline, motor oil or similar lubricant
• Hardware cloth
• Scissors
• Fiber-reinforced quick-set concrete

Instructions

1. Blow up your exercise ball to the size you wish your sphere to be. Be sure to plug the inflation stem after you've gotten the size right; you don't want air to escape while you're still working.

2. Slather the ball with WD-40, Vaseline, motor oil or similar lubricant. Although it's a little messy, it will help later when you want to separate the plastic ball from the hardened concrete sphere.

3. Cut swaths of hardware cloth. Wrap the ball with this rugged, galvanized screening, which will lend texture and structural strength to the sphere.

4. Coat the ball and hardware cloth with about a 1/2 inch of quick-setting concrete. Leave a hole 2 or 3 inches in circumference around the ball's inflation stem. Leave it alone for awhile and let it dry. Then, apply more concrete, depending on how thick you'd like the sphere to be. Smooth the surface with your bare hands before the final layer of concrete is completely dry.

5. Deflate the exercise ball and remove it through the small hole you left around the inflation stem.

Tips & Warnings

• Of course, there are many other ways to make spheres. One of the simpler ones requires only the act of blowing a bubble: Mix a thimble-full of dish washing detergent into a glass of water, and dip a cylindrical hoop the size of a 50-cent piece into the mixture. Draw it out and gently blow. You'll produce a half-dozen or so largely transparent, multi-hued bubbles -- perfect spheres, every one.

• To ensure your project cures properly, work in a high-moisture environment with as little air flow as possible.

References

• The Artistic Garden; Hollow Concrete Garden Sphere;