UK Pompeii & BBQ build

[david s]

Re: UK Pompeii & BBQ build

"There are refractory bricks and there is refractory concrete.

Everything else is not refractory"

How about cob, ceramic paper, hot face ceramic fibre, soapstone.... ? They are all refractory.

But I do agree that those heat bank bricks look dodgy, I think Faz should find out how they are rated instead of building it and find out (too late) the hard way.

[turkey]

Re: UK Pompeii & BBQ build

I believe in the UK there has been several successful ovens built with storage heater bricks, I don't believe they are simply concrete but each maker might use a different type of brick but they look similar to other bricks folks have used. A cross section would be an interesting photo to check.

hi Faz :-)

[Faz]

Re: UK Pompeii & BBQ build

Hey Turkey!

Here is a cross section of a brick. The bricks are very dense and I believe the dark flecks are magnetite.



I have had a blow torch on full blast on a piece of brick until it glows, then let it cool, then heated it again, then let it cool and then heated it for a third time until it glows. The brick was fine even with this aggressive temperature cycling so I am optimistic my build will be fine.

[deejayoh]

Re: UK Pompeii & BBQ build

Quick Bing search indicates that storage bricks are made from ferric oxide, instead of aluminum oxide used in fire bricks. If one can generalize based on the fact that Aluminum is a much better conductor of heat than Iron, then they probably won't absorb heat as readily as a normal fire brick. So you are likely to use more wood to get/keep your oven hot - but they are probably fine in terms of temperature cycling.

I would be more concerned with your plan to use terracotta tiles for your oven floor. As Brickie points out, those aren't temperature stable.

[Faz]

Re: UK Pompeii & BBQ build

The tiles are quarry tiles rather than terracotta. Quarry tiles are fired at high temperatures so should be fine for the oven - though they do look very similar to terracotta they are a whole lot tougher

Quarry tile - Wikipedia, the free encyclopedia

[deejayoh]

Re: UK Pompeii & BBQ build

The tiles are quarry tiles rather than terracotta. Quarry tiles are fired at high temperatures so should be fine for the oven - though they do look very similar to terracotta they are a whole lot tougher

Quarry tile - Wikipedia, the free encyclopedia

They may be tougher than terracotta, but they're not going to be tough enough for a 900 degree oven. Quarry tile is meant to go around a fire, not in it. I've used them as pizza stones in an oven, and even at those relatively low temperatures they crack and break.

Not sure why you don't just use the bricks as your oven floor.

[tonybaker]

Re: UK Pompeii & BBQ build

I would look more closely at the composition of those bricks, there have been some concerns expressed about the toxicity of materials used in fire bricks, and I doubt that the manufacturer of these heater bricks anticipated that they would be used this way?

[Bookemdanno]

Re: UK Pompeii & BBQ build

900 degree oven... Farenheit?

Quarry tiles are fired at close to 2000 degrees Farenheit...i still stand by them!

There's more levels of oven building than the Formula 1 style, full fire brick, high cost versions you all seem to be building here chaps... come on!

All our ovens are based upon the historical Vesuvian creations, which were probably...er definitely... not made from Firebricks, etc.

Actually, i doubt that firebricks are designed for cooking purposes and could pose health problems from the material make up too. I'd say Quarry tile, due to its fine graded natural clay base, and low absorpsion, would possibly be a better material for foodstuffs preparations.

Keep going Faz!! Guinea pig some new ideas for the knowlegde of all.
If it fails, just rebuild it! Its not the end of the world! See you on the "other forum".

[Bookemdanno]

Re: UK Pompeii & BBQ build

Night Storage heater bricks are pressed and sintered ferrous Oxide, that has a working temperature of 650 degrees centigrade. They probably don't have such a fast cycling time as firebrick, but release their heat more slowly.

Instead of a formula 1, more a 56 Chevy?

[Faz]

Re: UK Pompeii & BBQ build

Quick Bing search indicates that storage bricks are made from ferric oxide, instead of aluminum oxide used in fire bricks. If one can generalize based on the fact that Aluminum is a much better conductor of heat than Iron, then they probably won't absorb heat as readily as a normal fire brick. So you are likely to use more wood to get/keep your oven hot - but they are probably fine in terms of temperature cycling.

I would be more concerned with your plan to use terracotta tiles for your oven floor. As Brickie points out, those aren't temperature stable.

As the bricks are made of the oxides of iron / aluminium, the relative thermal conductivity of the metallic elements is totally irrelevant.

As I said early in this thread, these bricks are used for storing heat in electric heaters so I don't think I need to have any concerns about either their thermal conductivity or ability to store heat.

[Cheesesteak]

Re: UK Pompeii & BBQ build

Good looking build so far Faz.

To close the loop on this - I'd suggest getting the data sheet for the bricks from the manufacturer - or wherever they were purchased. If they are used to store heat in heaters - I can't imagine they would pose any kind of health risk - but you never know. I'd also want to know the max temp they can withstand.

If nothing else - getting a data sheet on the bricks might give folks here another option when building ovens. That's a potential plus.

I too am curious about the quarry tiles on the floor. Is that just for a smooth surface? Did you bond them to your floor with the same mortar used to construct the dome?

Your build (heater bricks and quarry tile) is definitely a first for me - so I'm looking forward to seeing how it turns out.

Best of luck.

[Faz]

Re: UK Pompeii & BBQ build

Thanks for the replies Cheesesteak, Bookemdanno and Turkey.

The quarry tiles are bonded to the floor using a wet mix of homebrew - which was used more like a traditional tile adhesive in a fairly thin layer. The bricks didn't have a fantastic surface so I thought tiling over the top would be better to give a clean smooth surface for cooking on.

I have looked for datasheets for the bricks but I can't find one on either supplier or manufacturer websites - so I am not 100% certain on max temps beyond the test I did myself which suggests they'll be fine. Others in the UK have used these bricks previously too and I cannot find any information regarding poor performance or degradation which is also re-assuring.

[Spinal]

Re: UK Pompeii & BBQ build

Interesting discussion - I'm quite interested in the quarry tiles.

In Italy there are two types of ovens, those put directly on firebricks (more modern) and those that use "clay" tiles to cook on. No idea as to what the clay is (still haven't found anyone willing to let me break their oven to find out)... but they are definitely used...

Would be quite interesting to see how you get along! When speaking to a distant uncle, he suggested I dug up some clean clay; mixed it with water until it became a slurry and then filtered it through a sieve before allowing it to dry before using this for the oven. Seems to have worked for his parents (and the oven is still running now)

M.

[Lburou]

Re: UK Pompeii & BBQ build

If those tiles work, you might have started a revolution

[Bookemdanno]

Re: UK Pompeii & BBQ build

You can season terracotta pots for use in ovens too, by cycling through several increased heating and cooling periods. Perhaps the Quarry Tiles, which are a fireclay product, become accustomed to the environment throught the initial drying and seasoning of the WFO.