Another Update: I made a video reviewing how well I thought the pizza oven works and has held up after a couple of years, you can watch that here • DIY Pizza Oven Review ...
Update: I’ve had a lot of questions asking for plans or want sized ball to use etc and I don’t have any plans I just made it up based on how big an oven I wanted if you want a bigger oven buy a bigger ball! I made the opening big enough to get a 35cm pizza in. I’m not a pizza oven expert this is just something I’ve seen lots of other people do and thought it would be an interesting concept to share! There’s so much out there online and I think it’s important to do a lot of your own research before you tackle any project. Also no cooking on cement isn’t poisonous, yes fire bricks would be better for the base but this was cheaper. I can’t remember how much cement and perlite I used, I think I bought 100l of perlite and had to buy more to make the base.
I have seen lots of other people make these and I thought I would give it a go as I love Pizza but have never been able to justify the cost of a store bought pizza oven.
I made this last year and saw a few cracks and honestly thought it had been a big failure so not knowing what to do with a massive piece of concrete in the garden I left it there for about a year, I kept thinking I should give it one good go and then probably smash it... well while I've been isolating myself due to covid-19 I've had more free time and finally moved it over near the house to give it a test and it worked great! I don't know what I was thinking, we've fired it up a few times now and its been working great. It also happily sat in the garden through a winter and summer and held up fine so I'm calling it a success. I definitely need a bit more practice with getting the heat right etc, might need an infra red thermometer to start getting it dialed in but I am very happy with the results.
The recipe I used for the concrete was 1 part cement to 4 parts perlite and then maybe just under 1 part water, you don't want to use too much water, just until you can squeeze it together in your hands to form a ball.