As my most recent project was a home-made Atlas Stone for Strongman training, using the plaster-of-paris-beachball method, I was looking forward to share my experiences with you afterwards and provide a little guide for you to follow.
However, in retrospect I thought the internet doesn't need another how-to on making Atlas Stones, especially from someone who did so with a less than average result:
Ain't she a beauty?
No, she isn't.
So instead of telling you how to make your own Atlas stone, I decided to tell you how NOT to make your own Atlas stone. Read a proper guide on casting your own stone first (here's one I recommend: Everything you need to know about making Atlas Stones) and then read on.
I made most of the following common mistakes. Be wiser:
1) Choosing the wrong location: Preferably, work in your garage or basement. You will need a location where plaster and cement splashes aren't a problem. You will need water and power supply. And you want to avoid rain, frost, and direct sunlight. I started out in a location without power supply, until I realized I would need power to operate the concrete vibrator.
Yes, you can still move to a different location with the finished plaster mould:
But I wouldn't recommend it. Transporting the mould in my car as seen in the picture above might have been the reason why it broke later on.
2) Not having the proper tools at hand: I believe anyone can build almost anything if he has the proper tools at hand and knows how to use them. Make sure you have all the tools you need ready before you begin to work. Leave as little to chance as possible, and avoid improvisation. Especially when working with material where time is a factor. You don't want to go on a search for a tool to vibrate the concrete while it gradually dries. Do you have buckets at hand to mix the plaster? Do you have a scale to weigh the cement? Do you have an air pump for the beach ball? Be prepared for any scenario.
3) Choosing the wrong beach ball: The best ball I could find was the kind of toy for kids to sit on and jump around, with two handles to hold on to. It looks a bit like an udder upside down. It had the right size and was sturdy, but the handles were farther apart than I had thought in the beginning. It forced me to leave a larger hole to pour the cement in than I wanted:
As a consequence, the stone lost some more of its spheric shape.
Try to find a ball the right size, as sturdy as possible, and - without handles.
4) Being sloppy when mixing the plaster: Mixing the plaster can be trickier than you think. Use too much water, and it won't hold. Use too little water, and it will harden before you can process it. I had no tools at hand to determine the proper mixture, so I went by feeling - and ended up with a bad mould and a lot of wasted plaster.
5) Being sloppy and impatient when making the plaster mould: When I started on the mould I thought this would be done within an hour. How wrong I was. It takes much, much longer. When I found this out, I grew impatient and simply wanted to finish this thing. The consequences were:
- A no-good base for the ball. This turned out to be the biggest blemish of the stone later. The bottom of it still looks worse than the top, although you would expect the opposite because the mould as a hole on top. Take your time to make a proper base for the ball. It's a way to start out well.
- Holes all over. When I deflated the ball and took it out to have a look at the mould from the inside, I was quite surprised how many holes and irregularities were left. I had to mix almost another bucket of plaster to correct at least the worst of those blemishes. Try to do it right from the beginning (although you will probably not get around fixing some holes either way).
- A broken mould. Just as I wanted to fill in the last bit of cement to finish the cast, my mould broke and displayed a large crack across the whole of it. I was lucky it didn't fall apart altogether (read why below). I don't know whether this happened because it was too thin, or because it was already blemished from the ride in my car. In any case, make sure your mould is thick enough.
6) Not using gloves: In case you didn't know, cement is acidic. I didn't know the first time I worked with the material, and my hands all dried up and were rough for a couple of days. I know, I know... who cares? But any professional who regularly works with cement wears gloves. They know why.
7) Not taking precautions for the case the mould breaks: In one way I was lucky when the mould broke, because the last minute before I began pouring the cement in, my instincts told me it would be a good idea to build this kind of safety net around it with a few wooden boards:
I had planned to fill all of it with sand, but had only little sand at hand. Only about a third of it was filled with sand, and I also threw a few pebbles in between the mould and the wooden boards.
I think it saved my stone. If you have just the slightest worries that your mould might break for whatever reason, better take this precaution than watch 200+ lbs of cement pour out of the mould you put so much work in.
8) Waiting too long to take the stone out of the mould: If you wait much longer than 24 hours before you take the dried stone out of the mould, you will have a hard time correcting any flaws on its surface. And yes, your stone will have flaws.
9) Not asking an expert: If you don't have much experience with cement or plaster, someone who is familiar with the materials can tell you things you would never have thought of, in a few words. For example that you should put a moist cloth over the opening of the mould if it is exposed to direct sunlight, or that it is ESSENTIAL to vibrate the concrete to get rid of excess air and water.
I know you want to do it on your own, but be a man and ask for advice.
10) Trying to cast your own Atlas stone using the plaster-of-paris-beach-ball method. You will save A LOT of time and headaches by using professional moulds if you desperately want to cast your own stone, and by simply buying a finished Atlas stone if you just want to own the thing.