Want to know another way to build your own pizza oven? Then have a look at this DIY pizza oven which made use of an exercise ball to create its dome!
Yes, you can use an exercise ball as the mould for your DIY pizza oven. It’s a convenient way for those who already have one at home, and it’s less messy than other pizza oven projects!
The detailed step-by-step tutorial below will tell you all you need to know and do, so start gathering your tools, materials and start making this project!
Is this the kind of DIY pizza oven you would like to build?
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You’ll need these materials:
- Exercise Ball
- Portland Cement
- Stainless Steel Needles
- Fire Bricks
- 3 x5 x 1/2″ Cement Backer Board Durarock/Fireboard
- Chimney 4″ x 2′
- Duct Tape
- Plastic Wrap
And these tools:
- Measuring Tape
- Cordless Drill
- Stape Gun
Top dome mold build: So after inflating my wife’s exercise ball, I measured the circumference to figure out the diameter for the circle cut out. After a high school flash back, you take your CIR measurement divided by pi 3.14, and it gives you the diameter. I cut out my circle, inserted the ball and boom – inside dome created.
FYI – There is an image that shows a bungee cord around the bottom of the ball. I had a fear of laying concrete on the top and the ball slipping through. I never used the bungee cord and I just simply inflated the ball slightly more, essentially wedging it.
Then it was onto the door mouth entrance. So with my dome height of 12.5 inches I went with a door height of 7.875 high, remember the ancients, trying to aim for a 63% ratio. I wanted to be able to pull the ball or deflate the ball from underneath so I wanted to pull out the door mold as well. So here is the set up on that. One thing I can say is, take your time. Just like a lot of things that you create that translates to many stages later in a project, the devil is in the details. Take your time to make those things fit better.
I had some trial and error on some things, like the white legs you see under the platform, they sucked and fell apart. I got them from my neighbors’ trash. Also I never thought it through until I was about to put concrete on the form, supporting the plywood/mold. When you’re messing with it, pretty much anything can hold it while you play with it. Then it dawns on you, about the weight and awkward shape you have to support from underneath.
Once the mold was ready or when you think it is, it’s time to just say go for it and mix up the concrete.
Concrete mix and molding to the top dome: So the mix I went with was Perlite/Portland Cement. I also added stainless steel needles for (fiber) strength.
I used a wheel barrow and your standard hoe with a chop chop action. I started with 2.5 buckets of perlite and a half bucket of Portland Cement. Mixed together well. Then I added the SS needles, i saw online that someone said about 5% SS needed. I purchased 10lbs so i figured about 4 lbs should be plenty. I hope that over use is not overkill that’s going to be an issue later.
Once it was mixed well, I added about a half bucket of water and kept the hose close to sprinkle additional water as needed. Don’t forget that once you have water in your mix, add very little water carefully a little goes a long way. If you add too much water you can always throw some additional dry into it.
If I were to do it again, I say this now, but at the time it seemed like a lot of extra work, I would have NOT used the ball as a form. Yes it did work. Yes it does look great. The thing I didn’t like is that I had planned everything out including the dome thickness and wanted to keep it at 2 inches. I even made a gauge to ensure proper thickness. But once I started to carefully add the material it just could not support itself going up the sides of the form. The top held, and the bottom/ sides up about 4 inches, any higher it would just slide down and thicken the bottom. Also the material feels very odd if you have worked with concrete before, the perlite makes it extremely light, airy and you feel the need to try to “compact” to the wall and the BALL gives and moves. So if you apply too much pressure the rest of the ball bulges and you see material moving. So with that being said, I might have put plaster on the ball, made a positive mold, and then transferred to a negative version of it. I didn’t take any photos of the “during” process for a few reasons: sweating my butt off, frustration trying to keep it from sliding all over, South Florida 90 degree weather, and did I mention sweating my butt off?
In the end, the bottom walls are about 3 inches thick and the sides about two.
Finish detail on dome top: So after I had explained that you couldn’t really push or compact the mix to aggressively or the ball would just give and bounce. After a day of curing I noticed one spot the size of an eraser head that i could see the ball through the wall. So I decided to skim coat the outside and inside. I skimmed the outside and after a day of curing I removed the molds.
I had been trying to figure out the best look for the outside and after I saw the results of the mix I decided to use some of the Portland cement and some SS needles to skim the inside and outside. It came out looking pretty good. Just remember, water is the enemy. Use sparingly. Obviously you want the proper amounts to create the cement to the optimal mix, but try not to use too much water in smoothing and what not. You’ll find that water might make it easier to smooth out the surface, but the right timing on the concrete (about 5 minutes after applying) and some elbow grease will do the same thing.
So for the inside and outside i just applied a light thin coat of the Portland and SS needles and made sure I took advantage of the stiffness and worked the mix into any holes.
Bottom floor mold: So the top is done. Now it is time to work on the bottom. Almost all the ovens I saw used either a large terracotta tile or a pizza stone on smaller ovens. I wanted fire brick. I wanted it to look nice, serve a function and be replaceable if they crack over time so they could not be “concreted in” like you might see on some larger ovens.
Also it is important to lay your brick floor in a herringbone pattern. Reason being if you lay your bricks parallel to the door, when you slide your peel in you run the risk of catching or chipping a front brick edge. Not good and don’t taste good either. Besides herringbone screams quality.
So I slid the top dome onto a piece of plywood, traced it out, then took my original circle cut out that I made for the exercise ball (giving me the inside circle of the dome) and had my two templates.
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