Improvising Material

[sjuniper]

Where we live (Andes Mtns. north of Quito) there are no firebricks - only low quality red bricks. Locals build and use brick ovens for cooking so have much experience. We are told that for the cooking surface they want to make a layer comprised (as far as I can tell) of local clay, crushed glass, and lava rock. Over brick domes they use mud (unknown clay content). Does this make sense to you for pizza oven? Especially the former.

[cynon767]

Re: Improvising Material

Depending on the composition and consistency, the lava rock can potentially be an insulator under the cooking surface. If it's lightweight and highly porous, is should be ok. Better than nothing, anyway. The more small air pockets, the better. Over the dome, a mud/clay mix could be used, but you'd be well served to mix in a fair amount of chopped straw or reeds to create tiny internal air pockets (again, for insulation, as well as for strength). This mix is what is called cob, and is traditionally used in many places for ovens. It could be used for the entire oven, if you wanted; or, use a mix which is high in straw content as an insulation layer.

Speaking of... What other insulation materials are available to you? There may be something more efficient than the cob, and insulation efficiency will help tremendously both with getting up to temperature and maintaining it.

There have been a few threads about clay/cob ovens here, some of which were pretty successful. There are a number of other resources online as well.

[dmun]

Re: Improvising Material

Just to bang on my favorite drum: Broken glass in not an insulator. Neither is sand, gravel, dirt, or clay. I'm all in favor of tradition, but if you can't get your oven up to temperature, it's not going to be much good for pizza.

As Jamie said, Lava rock can be an insulator. The ancient Romans used Tufa, which is a porous volcanic rock. There are lots better forms of insulation, and it's worth getting them if you can.

You can build the interior of your oven with plain red fired clay brick. It's not quite as good as firebrick, and will tend to crack and spall, but it will work just fine, if well insulated.

[sjuniper]

Re: Improvising Material

Thank you.
Although the thought of lava rock as an insulator makes sense, what I was asking about was for the surface of the oven floor, which needs to gain then emit heat, not insulate. The insulating material goes underneath that - right?
My partner here wants to just have the local "guys" build it according to local custom but I'm more cautious and want to be sure that "local custom" is not appropriate for a pizza oven. Locals bake bread in theirs, but not pizza. I've been unable to find out why they want to add crushed glass to the mix.
Steve

[dmun]

Re: Improvising Material

what I was asking about was for the surface of the oven floor, which needs to gain then emit heat

I'd surely prefer a hard fired red brick to some variety of mud, no matter what's in it: Your pizza oven fires won't get up to the temperature solidify the clay into ceramic, and it will always be soft. Remember, you'll be attacking this floor with metal tools, and throwing logs on it.

[100million]

Re: Improvising Material

Where we live (Andes Mtns. north of Quito) there are no firebricks - only low quality red bricks. Locals build and use brick ovens for cooking so have much experience. We are told that for the cooking surface they want to make a layer comprised (as far as I can tell) of local clay, crushed glass, and lava rock. Over brick domes they use mud (unknown clay content). Does this make sense to you for pizza oven? Especially the former.

The best why to find out is SIMPLE

Go to one of the local ovens and Fire it up and put a pizza in it

You will know with in a few minutes what happens

I got one better for you

YOU NEED TO THINK OUTSIDE THE BOX
With a population of 1,397,698 according to the last census (2001), and, as estimated by the municipality, approximately 1,504,991 in 2005,[2] Quito is the second most populous city in Ecuador

There has to be a place in Quito that has Firebricks for Boilers Commerical fireplaces or even fireclay... you and also try to find out refractory businesses, ceramic pottery businesses .....you will FIND IT if you look..... or try a brick yard or a stone yard that sells these kind of items

There has to be there if you are 1.4 million people....I know there is alot of poor people there and 99.9% or them never even heard of refractory or firebrick but it is there......THERE are professional that make boilers or commerical fireplaces.

Once you find fireclay you can make your only bricks

you can read this http://en.wikipedia.org/wiki/Fire_clay about what fireclay is made of and those item should be in QUITO

IF all else fails fire clay cost 7.00 usd a bag and we can ship you some

I hope this works

Chris

[Wiley]

Re: Improvising Material

You must be near Ibarra. It's been over 27 years since Quito, I arrived by narrow guage train from Guayaquil (including surviving an honest-to-goodness train wreck between Guayaquil and Riobamba). Those trains were both wood and coal fired and I have seen on PBS where they are still running those same old, worn out beasts. One would guess they are still lining the fireboxes with firebrick. If not proper firebrick then probably the closest you will find in country. They were constantly "rebuilding" and repairing the engines then (and I can imagine they still are) so if all else fails I would give the train yard a look over. They probably have the closest thing to insulation as well although there is the chance it will be asbestos.

Bests,
Wiley

[SCChris]

Re: Improvising Material

When we were in Cuzco, many of the locals build and use adobe ovens for daily cooking. I have included a photo below of an oven in the Machu Pichu area. This restauraunt oven is used mostly for pizza, we had one. The pizza was fair, not because the oven wasn't capable, but because the operator had his way to do pizza. You can see from the photo that the oven floor is brick.

Chris