transforming a wood fired kiln to a pizza oven?

[kimhamblin]

Hi everyone,

I have a wood fired kiln, a miniature anagama, on my property that isn't being used. I'm thinking I'd get more use out of a pizza oven and would like to transform it.

The firebox is 53" wdie x 46" tall x 36" deep. I was thinking of building a shelf inside and having the fire from below. But after doing some research, I'm wondering if it might not be better to build a wall between the firebox and chimney and build the fire right on the slab instead of beneath it.

Another question- would it be ok to use a slab of 2" concrete for the pizza base or would a stone be better?

Thanks for any and all thoughts!
K

[dmun]

That's a big kiln. If it's solid instead of insulating firebrick, I'd consider demolition and rebuilding as an oven. The one thing to watch out for is lead glaze contamination, heavy metals and all that.

Pizzas are usually cooked right on the firebrick floor, next to the burning fire. Heating indirectly would introduce multiple complications. Search "white oven".

[kimhamblin]

Thanks for the reply!
The kiln is actually much bigger than this, but this is just the firebox area. Its all made out of firebrick and has been used to fire ceramics. All of the glazes are food grade, so I think it should be ok. Wood fired typically has the ash from the fire creating the majority of the effects, so people tend to use very little glaze. It's been heated to 2400 degrees at least 5 times, so I think that would count towards the seasoning.

I was thinking of putting some sort of a slab mid way up so it wouldn't be as tall as 46", more like 26" or so. I've got extra fire brick and such material around and could build it up. I have a couple of concrete slabs too that could potentially work for the cooking area, but I'm not sure if they would crack. I coul also see about getting a stone that could fit into the space too....

I guess its kinda hard to explain!!

Thanks for any thoughts...
Kim

[david s]

I have a couple of concrete slabs too that could potentially work for the cooking area, but I'm not sure if they would crack. I coul also see about getting a stone that could fit into the space too....

I guess its kinda hard to explain!!

Thanks for any thoughts...
Kim[/QUOTE]

The concrete will crack. Try to use firebrick or kiln shelf. If the kiln was used to fire at stoneware temps the glazes used will not be harmful. Read as much as you can on this forum to get the general principles then go with what you think will work. Some pics would help.
Good luck, i'm sure you'll end up with something workable,
Dave

[david s]

I am currently building a small (4 cubic ft.) downdraft kiln and plan to use castable refractory mixed with course sawdust which should burn away during curing firing leaving a lightweight hot face insulating wall. I plan on casting a cylinder in three sections, then using my dome mould to cast a lightweight dome of the same material. It will have a single gas burner and a flue exit at the base incorporating a damper. Not sure if it will work, but can't see why not. Attempting to source a hot face insulating refractory was fruitless, all the refractory suppliers available products were almost as dense as their dense castables. Planning on firing to stoneware temps (1200_1300) This will be transforming a pizza oven to a kiln!

[david s]

My tests with the sawdust/castable mix (50/50 by volume) proved a disaster. The mix just never seemed to go off properly and even after two days was just a cake like consistency. I thought maybe the sawdust was slightly acidic and interfering with the calcium aluminate chemistry so I washed it, kept the drained liquid for PH testing and tried again. Unfortunately no improvement. Perhaps some chemicals used in wood treatment are the culprit. I tried the same with a 50/50 perlite and castable and got a good result, but unfortunately perlite and vermiculite are only good for 1100 C and I want to fire to stoneware temps. My next test was 50/50 rice, castable and I'm currently waiting for it to set. Fingers crossed.

[shuboyje]

I know a lot of guys making insulating refractories for forges and foundry's are now using polystyrene. They say taking a wire wheel to foam from packaging creates a good result. They then add it as an aggregate that burns out like sawdust leaving voids and hence insulation.

[david s]

Yeah, I had considered that, but polystyrene is pretty toxic when burned, so I'd prefer to use something more natural and safe. I just had a look at the rice/castable mix this morning and it has set up nice and hard so I think I'll go with that.
Thanks,
Dave