I received an email from Debbie asking me:

In the instructions given for the Hypertufa Hollow Garden Sphere, one of the materials needed was a deflatable ball.

Can you advise me where I would get such a ball? What size does it come in and what type material is it made of? (Guess you can see I don’t have any young kids at home nor any grandchildren. )

Thanks for your help. Oh by the way, I love the project info you send. My neighbor and I have tried a lot of the projects you have sent to me in your great little Newsletter. Debbie

My reply:

Hi Debbie:
I’ll be happy to explain this for you. You can use a plastic blow-up (inflatable) beach ball like the kind you’d toss back and forth to each other while frolicking on the beach which you can buy at most drug stores, Wal-Mart, etc. Just depends upon the climate zone where you live as to whether you’ll be able to find them year-round. Stores don’t usually stock them during frigid winter months. Or of course I am sure you’ll find them on the internet. And they’re pretty cheap.

The main thing, though about using these balls for a hollow sphere mold (form) is that they can deflate S..L..O..W..L..Y and without it being noticeable in the beginning. Most normally this is due to a pin-sized hole that allows the air to escape. I know in my case, as a kid, sometimes I’d find that my new beach ball was pretty much totally deflated within about a day. This was probably caused by a tiny pinhole leak.

Now … add the weight of a heavy, wet ‘tufa or concrete recipe pressing down on the ball. The weight helps to accelerate the air escaping. Some crafters have reported that when they came back the next day to inspect their sphere to see how it was curing – yikes! They found a pretty sad looking deflated and slumped down sphere.

Now … perhaps this “disaster” might prove to be an interesting sculptural form that once cured can be painted and utilized in some other fashion, but let’s just say most folks end up having to trash the project. So … “cheap” beach balls are quite OK most of the time and hold air without causing a project failure … but just be aware of the potential deflation problem.

Or you can get one of the big heavy-rubber inflatable types that people use to exercise with. These can be found at Wal-Mart or Target in the exercise depts. (as examples) and just the other day I saw some at T.J. Maxx for sale. This size ball would of course be used if you want to make a really big garden sphere. But deflation problems from small leaks most likely won’t be an issue for you.

Now, there are other smaller, sturdier type balls you could use, but you asked about inflatable/deflatable, so I am mentioning the most often used balls. You want something with a stem you can blow into or can hook-up an air supply to for automatic inflation. And the stem allows you to deflate the ball easily after your sphere has cured enough.

Good luck with your hollow sphere project!

I received an email from Charlotte who asked:

Did I miss something in understanding the concrete and hypertufa garden spheres instructions? Doesn’t the ball have to be deflated? If so – at what point? I’m so new at this that I would probably make a really stupid mistake about deflating the balloon too soon. Thanks for your help.

My reply:
Hi Charlotte:
Thanks for writing me. No, you didn’t miss anything … I guess I assumed that folks would know that you would have to deflate the ball after your ‘tufa or concrete garden sphere is cured hard enough – better to err on the side of a few extra days rather than deflating it while you still can detect moisture–meaning the mixture hasn’t cured enough yet.

Use your best judgment to gauge the right time to deflate it. Just make sure your sphere will be able to hold together.

Please read more about concrete garden sphere tips and garden sphere how-tos which will hold true for either hypertufa or concrete.

Sorry if this threw you for a loop. And please … no question is stupid  And I am glad you asked because now you are more knowledgeable about the issue of using the deflatable ball for your hollow garden sphere projects.

Good luck!

I received an email from Michelle asking:

I have made a hollow large (exercise ball size) sphere using a thin-set polymer-fortified mortar. Once the sphere is sealed, can it be placed in a pond – how long would it last? I’d love to see it float

My reply:

Hi Michelle:
About a floating sphere: I have no personal experience in doing this. However, if I were doing this, I would do a number of coats of sealant to be super-sure that it was sealed well, which I will assume would help with the longevity of the sphere lasting longer.

Please read my information about curing hypertufa and concrete, as you do not want to put uncured hypertufa/mortar/concrete into a pond. It could harm your fish and/or plants.