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GTA 04-25-2011 09:03 PM

High duty firebrick

Slight problem. The only firebrick supplier I can find can either get me High Duty brick (68% alumina) or insulating firebrick. Medium duty not available.

I read here Brick Oven Design | Choose the Right Brick Oven Brick

That both of these bricks are to be avoided, but since they're my only option, what should I do?

If it helps, I'm building a high powered electric oven (I live in a 30th floor flat, so wood-fired is impossible, sorry!).

Cutting them is my main concern, does anyone have any experience with this? I've read that using a saw wouldn't work. Would I be able to hand-cut with a chisel, or are the bricks simply too hard?

Thanks in advance

brickie in oz 04-25-2011 09:12 PM

Re: High duty firebrick
I have a friend who makes ceramic tiles for a living and his kilns have a very soft fire brick into which the electric wire is chased, they remind me of insulating fire bricks.
The wire is just a coil laying in the chase and retained with a pin.

Not the answer that you asked for but it may help.

azpizzanut 04-25-2011 09:42 PM

Re: High duty firebrick
Hello GTA,

You can't have a wood fired oven on the 30th floor of your building but you might be allowed a "pizza" kiln. Brickie may have given you (us) an idea worth developing.

There are some challenges and some obvious benefits to an electric "oven" and I don't think you are limited to using only fire bricks or soft kiln bricks as construction materials.

Consider the dynamics of a wood fired oven. Firebricks in the dome and hearth absorb heat from open flame. The hearth cooks the bottom of the pizza and the dome radiates stored heat to cook the top. To my thinking, the challenge is heating the hearth, unless you want to burn electricity for an hour to heat firebricks. Operating an electric oven/kiln draws a lot of expensive current. I think radiant heat from the glowing coils will cook the top of a pizza with only a little preheating period. Preheating a hearth or hearth substitute from ambient will be a design challenge and a good one for discussion on this forum. Can you give us some specifications to work with: dimensions of your planned oven, electric power available, etc? Will it be used occasionally for only a few pizzas or for a large crowd?


brickie in oz 04-25-2011 09:47 PM

Re: High duty firebrick
Ill ask my mate to take a pic so I can post it here.

GTA 04-25-2011 10:49 PM

Re: High duty firebrick
Hi guys,

Actually, I've already completed the design. I've put it together in Google Sketchup and I'll try to get some pictures on here.

It's a very simple design really: 2 steel cubes, one inside the other, with insulation between. The inside cube contains the brick floor and the heating element.

To answer your questions:

1. Electricity available is 240v mains.
2. Only occasional use, for myself and my wife mostly, occasionly for friends also.
3. Dimensions wise, the interior cube is large enough for one 12" pizza.

My only problem has been sourcing the brick for the cooking floor, and I'm wondering if anyone knows what is likely to happen if I use high duty bricks for this purpose.

brickie in oz 04-25-2011 11:32 PM

Re: High duty firebrick

Originally Posted by GTA (Post 111802)
and I'm wondering if anyone knows what is likely to happen if I use high duty bricks for this purpose.

Nothing will happen, the bricks are designed for a kiln situation to take high heat for a sustained time.

Cooking 1 or 2 pizzas per night they will outlast you. :rolleyes:

Save your money and buy 1 of these it will work out cheaper.
The link is here.

I bought my son who lives in a shared house one of these and he is most impressed with the performance, he's even had friends over for pizza parties..:D

GTA 04-25-2011 11:44 PM

Re: High duty firebrick
Well thanks, but by "what will happen" I didn't mean "Will they last". I know they're durable.

I was referring more to the concerns in the brick primer article I posted a link to, namely will they get too hot for good cooking? Will they take a long time to heat up? Is it possible to cut them by hand?

And yes, I'm pretty much making one of those, but it should be better. I've used one of those machines before, and they have a number of flaws which my oven will address.

And as for expense, I don't think anyone on this forum is really looking for the cheapest pizza; we're looking for the best pizza. I don't really care about the money.

GianniFocaccia 04-26-2011 06:40 AM

Re: High duty firebrick
Just because high-duty bricks are constructed to operate at a higher temperature doesn't mean they have to. Once you get your floor up to the desired temperature (or a little higher), wait a bit for it to settle down and equalize, and you'll have the proper temperature floor. The trick will be to get the dome temp to match your floor temp. Like the rest of us, it will take a few times to get the process optimized.

brickie in oz 04-26-2011 11:59 PM

Re: High duty firebrick
1 Attachment(s)
Here is the inside of the tile kiln.

The wires are live so great care has to be taken if going this route, when the kiln is active the door is closed and protected with an interlock to stop you from killing yourself.

But, if you done it right in a pizza oven it would work.

In the pic the middle of the brick is chased out, I would have gone for the edge of the brick myself.

The wires are connected via a straight connector almost visible on the front left of pic.

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