Fire bricks versus 'Pressed Reds'

[Capt. Toddy]

Is it worth the extra cost. I keep hearing two sides to the story about building an oven using fire bricks or normal solid bricks.

Can anyone shed some light on this before I go and spend my hard earned dollars on this part of my oven.

If anyone has an oven they built using normal brincks, have you had problems with cracking or deterioration of the inside of the oven? If so how long after building the oven did these prblems occur?

Rod

[nissanneill]

Re: Fire bricks versus 'Pressed Reds'

Hi Rod,
only this morning I had a talk with an Adelaide engineer (married the girl next door - true!) and works out of Canada for a company who design and build blast furnaces all around the world.
It was exceptionally interesting, but I wanted to breach the use of 'common reds', the fired clay building bricks used in house construction, but not the ones with holes through them.
Most of these bricks, even those 50 to 100 years old are more than suitable for our oven building as they are fired at well over 1000˚C to vitrify the clays.
However, be aware that some bricks haven't been fired as well as others and only use those which break rather than fall apart when hit with a hammer.
Russel Jeavons used 'common reds' in his commercial pizza ovens and several other Australian members have also used them as the firebricks are too expensive over here.
Check Tim's oven for more details of his build and he is thrilled with it's performance.
I am about to write a comprehensive thread on bricks for use in WFO's and people can then decide for themselves.
Firebricks in the US are cheap and easily available throughout the country. They are fine but offer no distinct advantages for the relatively low temperatures that we achieve in our ovens.
When I build future ovens, I most certainly will not use firebricks but 3" solid fired at 1200˚C pavers from Littlehampton Bricks (a local brick manufacturer in the Adelaide Hills).

Cheers.

Neill

[david s]

Re: Fire bricks versus 'Pressed Reds'

Neill,
I agree that the common reds are probably adequate for a home oven which is used fortnightly on average.That would equate to about 250 firings in about ten years. But I think it might be a different story if the oven were in a restaurant and being fired every night. I recall seeing many fireplaces in Victoria, which get a pretty good working over in winter, with crumbly red brick floors. I don't think that it is the temperature the bricks are fired to which is the crucial factor, but rather how refractory the materials the bricks are made of, that is the most important. Iron in Australian soils is predominant and gives the characteristic red colour, but also fluxes up the clay and makes it less refractory, hence the high price for the rarer fire clay.

[Capt. Toddy]

Re: Fire bricks versus 'Pressed Reds'

I was quite surprised when I was ringing around to get prices for refractories and they were roughly 3 times the price of solids. $3.30 was the cheapest price I could find.

If they were around $2 each I'd consider them for sure but I need about 200 bricks and $660 is just too far out of my budget.

As indicated to me in another thread there are 34 members on this forum from Down Under. Can any of these members point me to bricks around the $2 mark.

Rod

[david s]

Re: Fire bricks versus 'Pressed Reds'

I remember about 30 years ago the brickworks at Cooroy, Qld. were making house bricks from a creamy coloured clay that a lot of potters were using for kiln building, as the bricks were quite refractory, but no dearer than standard reds. I got a pallet load and built a small kiln from them which I used to fire to stoneware temps (1200 C+) 30 years is a long time, but maybe they still make them.

[RTflorida]

Re: Fire bricks versus 'Pressed Reds'

O.K. guys, this topic seems to come up at least once a week. I believe dmun mentioned that someone in OZ needs to become a firebrick importer.....I will second that motion.
It seems Australia is becoming the greatest growth opportunity for the WFO community.
I gotta tell you, with the relative ease that you can order a container load of just about anything, I would be odering a container from the US (or wherever else they are cheap) and offering them to the local WFO community at a fair price. I've also noticed that several forum members have mentioned they are building or have built several ovens....Why not jump in the deep end and source the proper materials and make a few bucks at the same time?
The only drawback I see would be import tarriffs.....are they really high in Australia?

RT

[nissanneill]

Re: Fire bricks versus 'Pressed Reds'

RT,
I imported two clubman kit cars from the UK and freight was US$5000 and there was 45% import duty PLUS the wharf duty, import inspection fees and import agent fees.
Importing them is not an option for this little duck.
Any way, what do firebricks offer as an advantage over a good solid red or fired clay paver?
All my research and questioning has come up zilch! Only those with a vested interest in your money might find a slight advantage at a severe economic disadvantage.


David S,
there are a couple of commercial pizza wood fired ovens here in Adelaide, Russell Jeavons has 2 and they are used commercially for 5 years without any spalling or cracking. See the picture that I took a year ago. It is up with a host of others under WFO restaurants

Neill

[RTflorida]

Re: Fire bricks versus 'Pressed Reds'

Neill,
By no means am I an expert. I can only relay "opinions" from several sources (3 masonry suppliers and a refractories suppliers as well as more "opinions" I have found on line). All seem to agree.
It is not the firing temp. of the bricks, it is the CONTENT of the bricks. I can't speak for the bricks available in your area, but any kind of fired or non fired clay brick found in the US is not suitable for long term use involving the cycling temps we see with ovens, fireplaces, kilns, etc. This isn't some conspiracy by the manufacturers to force unneeded expensive products on the public...common clay bricks over time will not handle the heat up, cool down cycling - again, it is the content, not the temp they were fired at. Exactly what does this mean to us, the average oven builder, I don't know. All I know is that I may live out the rest of my life in my current home (or I could be forced to move next month) and ANYTHING I do or build is done to last a long time. Whether it is 6 months, a year, or 20 yrs, I don't want crumbling, spalling bricks dropping on my food (MY opinion this time). All indications are that it WILL happen at some point.

Now the Russell Jeavons thing.....no offense intended, but just because he has done it, does not make it the gospel or even the right thing to do.....he may very well have had budget issues at the time and was just looking to save money (hey, we all have our limits). Also, his ovens are commercial, therefore temp cycling is not nearly as big an issue as it is for a home oven or fireplace. His ovens most likely never drop back down to ambient temps and always stay in the cooking or baking range......this is a BIG issue (for this reason only, the firing temp of his bricks DOES help).

All that said, if you have the money - do it right and splurge on the firebricks and good, plentiful insulation. If money is REALLY a concern and you are not just trying to cut corners, then go with what you can afford....any WFO with a bit of insulation is better than no oven at all.
Gotta say, I'm done with this topic until the day I become a refractories expert and brick maker.....there are just too many "grey" areas that unless you are in the business and have years of actual experience manufacturing and testing...you are just not going to know the REAL answers.

RT

[nissanneill]

Re: Fire bricks versus 'Pressed Reds'

Well put RT,
there are many factors to consider, and there are many types of brick that are available as well as financial considerations for the oven builder.
It a choice that people need to explore and like everything else under consideration and availability, make the one that is most suitable for their circumstances.

Cheers.

Neill

[Adrian]

Re: Fire bricks versus 'Pressed Reds'

I've talked to a few people in Perth who have made WFO and used the cream coloured bricks. I also stopped in at Midland bricks last week and had a chat, explained what I wanted to do, and asked if the solid creams would work. The reply I got was the cream smooth solids are the best standard brick for WFO, due to higher thermal mass. They are not designed for ovens or kilns, but are fired at over 1000*C and should have no problems with your average backyard oven.

This matches well with Russell Jeavons' opinion in Your Brick Oven, so that's good enough for me!

[nissanneill]

Re: Fire bricks versus 'Pressed Reds'

Adrian,
the ovens are only designed to reach say a round figure of 500˚C whereas a kiln can be required to go to over 1000˚C. I have a Ward Kiln that is used for ceramics and pottery which I use for annealing and firing ceramic inks on glass and pottery. The high fire inks are fired at 860˚C so the bricks need to be better than the common reds or in your case the creams.
Back to your ovens. If the brick is fired at over 1000˚C and is only going to achieve a half that, then it will perform OK.
As RT posted earlier, the thermal shock of continually heating these bricks from cold to baking temps over a 20 or 30 year period, say each week or fortnight, MAY show sign that a firebrick may not.
I would not use a brick that crumbles when hit with a hammer, but I would use one that breaks/splits.

Cheers.

Neill

[Johnny the oven man]

Re: Fire bricks versus 'Pressed Reds'

For anyone wanting 40% alumina firebricks and are willing to take a full pallet lot, we can offer @ $3 each. Melbourne based.

[bimbo]

Re: Fire bricks versus 'Pressed Reds'

how many are in a pallet load johnny?

[Johnny the oven man]

Re: Fire bricks versus 'Pressed Reds'

320 pcs sized 230x115x75.

[Volongo]

Re: Fire bricks versus 'Pressed Reds'

Neill,
I agree that the common reds are probably adequate for a home oven which is used fortnightly on average.That would equate to about 250 firings in about ten years. But I think it might be a different story if the oven were in a restaurant and being fired every night. I recall seeing many fireplaces in Victoria, which get a pretty good working over in winter, with crumbly red brick floors. I don't think that it is the temperature the bricks are fired to which is the crucial factor, but rather how refractory the materials the bricks are made of, that is the most important. Iron in Australian soils is predominant and gives the characteristic red colour, but also fluxes up the clay and makes it less refractory, hence the high price for the rarer fire clay.

Davids, How much do you buy your firebricks in Townsville?