Oil Drum Pizza Oven

This project is a remix of an Ugly Drum Smoker (UDS) and a Gym Ball Pizza Oven. I started making an UDS in 2019 but at the start of this year I decided to go vegan for January and never went back. As much as I love pulled pork and slow cooked BBQ meats I have found that there isn't much need for an UDS in the vegan cooking life style! So I decided I needed something else as a foodie focus and found that I really loved a simple Pizza Marinara so I set out to build a pizza oven.

I looked at the common vermiculite Gym Ball (like this one on Food Related) or clay cob approach and whilst it looked good I wondered if I could use the barrel I had sourced and cleaned for my UDS project to create a hard wearing and good looking Pizza Oven. I couldn't find anything else like this so I decided to adapt what was out there and see what happened.

The overall cost of the project was pretty low - about £70 excluding the optional stands - significantly less than any commercial outdoor pizza oven. The legs could be made from timber, blocks or steel but I picked commercial Builders Trestles as they were easily available and rated up to 400KG. The drum is very heavy when it is finished. The process was relatively easy and I did it over several weekends to allow each stage to dry out before moving onto the next one.

Supplies

• Oil Drum with removable lid - mine was free but available on e-bay for around £10-£30
• Vermiculite - I used just under 2 x 100L bags of Micafil granules (approx. £20 each from Selco)
• Cement - I used 1 x 25kg of Multipurpose cement (approx £5)
• Fire Brick - I used 6 fire bricks from e-bay, recycled from storage heaters (£3)
• Paint - I used 2 x 500ml cans of Very High Temp paint from Halford (approx. £10 each)
• Legs - (optional to raise the oven) I used 2 x No.1 Builders Trestle Stand (approx. £25 each from Selco)

Step 1: Prepare Your Drum...

I wasn't 100% sure what had been inside my drum so I decided to clean it as much as I could and that meant starting with a fire. I burnt a load of scrap wood and got it hot enough to loosen all the paint on the outside and the lining on the inside. Once I'd burnt it out I got in with a wire brush on the end of my drill and took it back to bare metal as much as possible. It took ages but I think it was worth it. None of the cooking takes place on the metal as it's separated from interior by several inches of insulation. Once I'd done this I painted the outside with the high temp black paint.

Step 2: Prepare the Vermiculite Mix...

The mixture of cement, vermiculite and water creates an insulating layer that keeps the heat in your oven and cooks your pizza. The better the insulation the quicker the over heats up and the longer it will hold the heat. I went for about 100mm thickness as much as possible.

Looking around I ended up with a mix of 5 parts vermiculite, 1 part cement and two parts waters. I used an old plastic tub and mixed it with a trowel. If you make a ball of the mix with your hands it should hold its shape - its a pretty firm/dry mix.

I started with the barrel vertical and created the surface that is effectively the back wall. I used a bit of wood with a hole drilled into 100mm from the bottom to mark the barrel. The barrel was filled with the mix and then the end of the wood to flatten it down. I left this to dry for a good few days before the next stage.

Step 3: Make the Cooking Surface...

At this point I transferred the barrel onto a horizontal surface and marked the level where I wanted the floor to sit - I made sure it was wide enough for a decent sized pizza. Fill it with vermiculite mix until you get to the point where you can sit in your fire brick. I used 4 at the back and then 2 rotated 90 degrees at the front to make it slightly wider. Putting the firebricks in before the mix is totally dry helps stick them into place. I filled around them with vermiculite mix and built up a couple of ledges to use as the start of dome. Again I left this to dry (about a week this time).

Step 4: Make the Curved Roof...

To make the curved roof I used a wooden form. I got lucky here and had an old bass drum skin that I cut in half. It fitted perfectly with the right amount of gap and using both halves end to end it filled the full length of the drum. I covered the wood with plastic wrap to help get it out afterwards. To get the vermiculite mix into the gap it was easier if the drum was stood up vertically again.

Before I put the second wooden form in I cut a hole for chimney which was formed around a coffee tin. I pushed it into the hole once I had filled the mix up to that point. Again I pressed the mix flat with a wooden

Step 5: Add the Legs...

I originally intended to re-use some old aluminium chair legs for the base but it turned out that the overall drum and vermiculite mix was seriously heavy. Two of us struggled to lift it onto the legs which bent in the process. To make sure the unit was safe I bought some heavy duty builders trestles (you can also find them cheap on ebay) but I was too impatient to wait! I added some wood planks to one side to make a side table which has been really useful for holding pizza's when they come out.

Step 6: Get Cooking...

I left the oven to dry for a few weeks and then started with a small fire. The first time I cooked it took me about 2 hours to build up the temperature. Once the oven was heated up I measured about 450oC on the roof and 150oC. The temperature on the outside of the drum has so far never gone about about 75oC at the top of the dome and on the back wall its as low as 30oC. As its open at the front its not as hot as dome oven but it nicely cooks a 12" pizza in about 8-9 mins. The second time I used it it warmed up in about 45 mins.

I have been cooking on pizza trays so far but I might test cooking directly on the stone once I get a paddle sorted. The results have been fantastic and very consistent.