Eco-Friendlier Concrete Orbs

A while ago I shared this fire-pit project made from a stepping stone and three concrete orbs. I was surprised at how many overseas readers asked where they could buy orbs when, in South Africa, you can get them at every garden center.

Then it struck me, people in other countries aren't so selfish with their pavements (sidewalks). Here, orbs are used as bollards to keep people from parking in front of your house. Illegal but very common. So actually you should be glad that you can't find them!

The question remains, how do you make concrete balls? A search of Pinterest revealed using wire mesh, exercise balls, bowling balls or, horror of horrors, glass lampshades that you then shatter to unmold. That's just awful!

All good and well to jump on your environmental high-horse but what can one use instead? In all truth, it took me months to figure out...

You use a plastic lampshade that can be reused. Duh!

I picked up this particular one from a junk shop for less than what I pay for a cappuccino. And even if you were buying a brand new expensive one (because the good quality ones aren't cheap), your investment will be paid off after making just two balls - the concrete cost me less than a sixth of the price of one ready-made orb!

It’s so easy, this the first time I've ever cast concrete and it came out great. The fact that my shade it has an inward protrusion at the neck makes it less than ideal, yet I still managed.

So, take a nice, big, strong plastic round shade and mark a line along the circumference. Next, take a hacksaw or box-cutter and cut a clean line to halve it. I got some muscle to do this for me. Placing the shade on a bucket or pipe whilst cutting is a great idea.

Two beautifully cut halves.

After scrubbing with a brush and water to remove dirt, tape the two halves together again using lots and lots of duct tape, not just one layer.

Most casting tutorials I saw, suggested using cooking-spray as a release agent. I made a half-hearted attempt after the halves were stuck together again but it was too difficult to get inside and I didn't want to waste spray on a shape that, to my mind, should unmold quite easily. Mmmm, perhaps that's why I also cannot bake cakes - because I always know better than the recipe.

Then I mixed some screed-mix. (First pass I asked for concrete mix and came home with a bag of rough gravel). As is my habit with cake baking, I totally disregarded the suggested amount of cement that came with the bag and added some more. It couldn't hurt, could it? Adding water was also a bit of a thumb suck but I am sure that the concrete that you buy will be finely textured and come with meticulous instructions.

With the shade perched on a bucket and using a small potting shovel, I filled it with concrete.

I was a bit worried about the extra water. And in theory you should vibrate or bang it a bit to remove air. Alas, me and the cake recipe again...

The time it takes to cure depends on the ambient conditions. I left mine for about 3 days. I think the plastic could delay the curing time a bit since it is more waterproof than say, wood or cardboard. The area that is exposed to the air is not the main concern when it comes to drying. Instead, the area that you should watch out for is the bottom.

To my great surprise the part with the inverted neck came out very easily. I loosened the mold with gentle bangs of a hammer and screwdriver. I suggest you use a flatter object such as a metal scraper instead of a screwdriver otherwise you end up damaging the line along the seam. It helps to work on sand or grass so that the orb doesn't roll around so much.

The bottom part was another story, probably because it was still a bit wet or because of the absence of release agent. Nevertheless, I kept on gently banging with the hammer and even resorted to my baking palet knife. Eventually it came out. I will leave it out to dry for a couple of weeks before sealing with Gripseal.

But there it is...a perfectly passable concrete orb at a fraction of the price of a bought one.

No boy, it's a bit heavy to play with, even for a huge dog like yourself.

And the best part is that the mold can be used again!