Fire brick

[spt]

Hi - I am having trouble sourcing fire bricks in New Zealand and the best I have come up with are from Placemakers but they are classed as a High Duty fire brick. It mentions in the FB plan these bricks should be avoided, but has anyone had any experience using these bricks - good or bad. The brick manufactures recommend its use in WFO's but I do not want to go to the trouble and expense of building an oven and find it not good to use. The plan mentions High duty bricks get too hot and burn breads etc, but could this be controlled by the size of fire and timing? Any thoughts would be appreciated. Regards Dave.

[Neil2]

Re: Fire brick

"bricks get too hot" ??

No such thing. You control the temperature of your bricks. For some reason fire brick seems to be difficult to obtain down under. Maybe it is a problem with terminology.

Maybe some of our Aussie posters can help ?

[james]

Re: Fire brick

Hi guys,
Sorry this has become so complicated down under. I've been thinking about firebricks, industrial development and economic history, and it's pretty interesting. In the US, our refractory industry supported the steel industry and they have both shrunk in unison to where they are only a fraction of what they once were. It's getting harder to find good quality, cost-effective refractories in the US. Plus, with fewer true brick fireplaces being built, there is even less demand.

Back to what Neill said earlier, Australian and New Zealand sort of missed the heavy industrial revolution, and never had a refractory industry.

Right?

It makes sense that if firebricks are crazy expensive, that you would use red clay bricks.

Anyway, here is a table for Low, Medium and High Duty firebricks from our producer (they also makes Super Duty, but we won't talk about that).

I think that a High Duty firebrick would make a pretty weird pizza oven. It would want to shoot up to over 1000F and as long as the fire was hot, it would just stay there. When the heat was gone, it would probably cool down too fast. Those bricks are made for metal furnaces -- not food. But that is a "High Duty" brick by the definition below. It is very possible that some manufacturers will call our Medium Duty firebrick -- High Duty.

Ask about alumina, density and service temperature.

Firebrick comparison

Low Med High
Alumina (%) 30 38 50
Density (lb/cu. ft.) 127 135 150
Service Temperature (F) 2372 2462 2642

I hope this helps!
James

[james]

Re: Fire brick

Here is it as a PDF.

[james]

Re: Fire brick

The more I think about it, we should have published this table on FB.com and in the Pompeii Oven eBook a long time about. It will help builders talk more articulately with suppliers.

LOL -- I could even rename the firebricks in the Pompeii Kit as High Duty (good for marketing). :-)

James

[spt]

Re: Fire brick in New Zealand

Hi James and all - I have got the spec sheets for the fire bricks today and I am happy they are a medium duty brick even though described as high duty brick. James thanks for the attachment fire brick comparison. The bricks I can source have 36% Alumina, density 132 lb/cu.ft. and temperature rating of 2498 degF which is very close to medium duty. For anyone in New Zealand they are manufactured by Shinagawa Refactories Australasia in Huntly and called the SHIRAL 35KTW dry pressed high duty fireclay brick. Unfortunately they cost $NZD6.14 each but are good quality. Thanks for the info once again. Regards Dave.

[dmun]

Re: Fire brick

Yikes! $4.41 usd per brick, for a differential to James' price of 3.21! Ocean shipping of pallet goods is not ruinously expensive, you've got to be close to saving money by having the FB kit shipped to you.

[jlb922]

Re: Fire brick

I am planning to build a backyard oven using the Pompeii Plans for a 42" oven.

So far I have been able to find two types of firebrick locally:

Low-duty - 28% Silica, $1.05 each = $210
Med-duty - 41% Silica, $2.72 each = $544

What would the difference be in how the oven would perform and be used? Does one type heat up faster or hold heat longer? I would like to make pizzas in the evening and bake bread and roast foods the next day.

Is it worth the extra $344 for the medium duty brick or would that money be better spent on additional insulation?

Jeff

[dmun]

Re: Fire brick

Is it worth the extra $344 for the medium duty brick?

Absolutely not. Use the ordinary firebrick if you can get it.

would that money be better spent on additional insulation?

Unlike brick alumina content, insulation is critically important. Lack of proper insulation is the number one cause of oven dissatisfaction and disuse.

[GianniFocaccia]

Re: Fire brick

Not being familiar with alumina properties, can anyone decipher the attached Pacific Clay 'fireback' MSDS? I can only assume that what the mfr terms Aluminum Silicates is "alumina' but have no clue how the 'percentage by weight' converts to actual content. A number of FB folks in CA have built Pompeii ovens from these bricks (standard firebrick size weight etc). I would be curious to find out how they perform.

John

[brickie in oz]

Re: Fire brick

Most modern house bricks are fired at a much higher temperature that any domestic woodfired oven can ever hope to achieve.

I seriously cant see what all the fuss is about with "fire bricks", its not like you are building a furnace to melt steel or fire ceramics.

[kebwi]

Re: Fire brick

I believe firebricks spall less at high temperatures, less grit in your pizza. The question isn't so much whether the brick can survive the high temps once as it is whether the brick can survive dramatic temperature swings (1000F) over and over and over again.

[brickie in oz]

Re: Fire brick

whether the brick can survive dramatic temperature swings (1000F) over and over and over again.

Has anyone on the forum tested this?
Id love to see the data..

[kombiman]

Re: Fire brick

Most modern house bricks are fired at a much higher temperature that any domestic woodfired oven can ever hope to achieve.

I seriously cant see what all the fuss is about with "fire bricks", its not like you are building a furnace to melt steel or fire ceramics.

It is not the temp they are fired at but their mass and ability to embody with energy (heat) that the brick will release (decay) and cook our food. Non fire bricks don't have the mass aside from spalling etc.

People make fine ovens with other bricks, stones, earth and rocks but a fire brick oven will be stable in heat in/out and if well insulated stay hot for ages.