Choosing the right Bricks for building your Pizza Oven
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- Опубликовано: 12 май 2020
- Why not build a pizza oven using pressed red bricks? We went full nerd on the question, building a test rig to show the effects thermal shock on different bricks. Learn more: thefirebrickco.com
Our custom Thermal Shock Test Rig is effectively a gas heated furnace with a series of pneumatic actuators, controlled by an Arduino Uno. The idea is pretty simple, we know that it's not actually high temperatures that cause pressed bricks to fail, it's repeated cycles of thermal shock - rapid change in temperature from cold to extremely hot.
For more information on building a high quality Wood Fired Brick Oven that's going to last a lifetime, check out our website; www.thefirebrickco.com
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Хобби
I just sat through a 15 minute video about bricks for no particular reason and found it one of the more interesting videos I've watched recently. 🤣🤣 good video
Glad you enjoyed it!
Haha, yeah, I wanted to know what fire bricks actually do because I don't really know about them. I sat through this 15 minute because it kept my interest. Still don't know what fire bricks are used for but I know now that the brick can tolerate thermal shock. So, I guess I learned something.
Me too, loved it
Me too.
Yeah he did a nice job with the test rig too.
Thumbs up for the sheer amount of effort you have put into this! From building a jig, to writing arduino code to automate this jig and making a clear video explaining all these concepts without bias - Thank you!
Thankyou so much Subbu - I really appreciate the encouragement!
No kidding!!!
Congratulatórios , you just went from "I think" or "I was told" to actual real proof, Hats off on your effort and rigurosity.
Thankyou Gregorio! Much appreciated!
This video has given me the confidence to build my domestic pizza oven from the cheaper red pressed bricks and replace them when necessary. Thanks!
Good stuff Anthony! Jump back in here and give us an update in a while to let us know how it's going over the years.
Replace them? You mean rebuild your entire oven right? I’m all for using red brick for an oven but replacing means rebuilding to me.
Yes, exactly what I meant! Rebuild it when required.
@@anthonykinrade8642 I would think it would last a generation. Leave the door on while cooling and it would take 2 or 3 days to fully cool. Same with heating, heat it up from morning until night or vice versa.
That's short minded if not stOOpid... enjoy the redbrick crunch on your pizzas.
Never been so interested in wood fire ovens now,… the bricks, the temperature, the pre cast vs brick decision, and even cooking times amaze me. Great content. Now I just got to save up for one!
Thanks heaps Shaun!
Straight forward, to the point and honest. Very few can pull this off. Thanks, my friend.
Great video. This actually makes me feel better about using regular old red bricks in my outdoor pizza oven. Mainly because it’s temporary and will only be used a few times. If I’m to build a permanent one definitely going with the fire bricks.
This is exactly the intent behind this video - glad to hear it was helpful!
The old Russian stoves used for hundreds of years in the coldest parts of Russia were composed of 500 to 800 red bricks with (white) plaster over top many of them. They simply didn't have firebricks until a few decades ago and probably still don't use them in "remote Siberia." The reason these ovens lasted for 20 or 30 years is, just like he said, once they were brought up to temperature (say, the first day of October,) they were heated twice a day, every day through the winter, and the bricks were not allowed to "cool down" until, say, June 1. The thermal mass, as a whole, kept way above room temperature. I'm sure they had to do some minor repairs on the firebox every five or 10 years, but not on the rest of the brick stove.
Spot on - and they would have heated them up fairly slowly too, to avoid thermal shock at the beginning of the cycle. If you used them that way the vast bulk of that construction would last for a very long time, but eventually the brick in the firebox would need to be replaced.
Respect for this mans building potential. Such an awesome rig. Dont forget the steel going in and out of that oven. Another modern marvel. Thanks for putting together this video.
You're very welcome!
Thank you now I know about thermal shock and bricks... 🤓🤓😢🤓🤓🤗🇨🇭 👍👍👍👍
You're welcome!
At last someone who knows what they are talking about. Great video.
Thanks George!
Thank you for the info. I am just about to start my oven so this will be so useful. Much appreciated.
Glad it was helpful!
Thanks for this information. I have wanted to build a brick oven for quite some time and any new information I find is very helpful. Thanks again! Very much appreciated information! 💞
Thankyou for the encouragement!
Awesome content. I just viewed a video recently about building a pizza oven using the pressed red bricks. A lot of the comments mentioned that these bricks would explode if used in this way. Your demonstration was good to see, so that I would feel more comfortable knowing the bricks won't explode during use but develop cracks over time. I thoroughly enjoyed your presentation!
Thankyou Pete! Much appreciated!
@@TheFireBrickCo but are red building bricks food safe?
Yes they all are food safe
Love the test rig ..... well done 👍
It was SO much fun to build. Definitely want to play around with more of that kind of thing when we get some more time...
Thank you for this video and explanation!
Glad it was helpful!
Coolest test tig.. tests done very nicely. Enjoyed your full video though watched it without any context. Glad i watched it. Cheers mate. Keep up the good work.❤
Thank you!!
Thank you so much for your time and expertise to educate us on this.... really appreciate your efforts.
Thanks
Thanks Amit!
Awesome video! Really helpful for my upcoming project. Thanks!
Glad it was helpful!
Thank you. I was making a wood fired oven in the garden and i came across your video. Now i know what is thermal shock and flaking.
You are welcome!
This was very helpful. Thank you.
Glad it was helpful!
excellent tutorial. I learned a lot, thank you.
Glad it was helpful!
Loved the honesty, amazing video
I appreciate that!
Great Video, Very informative!
Glad it was helpful!
Very useful and instructive. I'm just building a masonry stove and tossing up between fire and pressed brick, I get what you're saying. Excellent presentation by the way, good, clear and down-to-earth: very Oz. Thank you!
Thankyou very much!
Thanks for the information
You're very welcome Ralph!
Great presentation,you really educated many views on this subject.👍
Glad you think so!
thorough and concise - good well done. whenever i get around to building an outdoor pizza oven, i think it's safe to say the investment in fire bricks are well worth it. cheers!
Glad it was helpful!
Ive been looking into making one as well theyre not too much more expensive than a regular brick thankfully unless youre building a really big one and even then you could get away with the structure being clay and the internal cooking part being fire brick
Excellent video. Great explanation.
Thanks Danny!
This was very informative and probably will save me some heartache when I finally get around to building that pizza oven. Thanks for making it!
No problems Marty!
Very informative video. Thanks guys.
Our pleasure!
Very nice demonstration , very technical.
Thankyou!
as someone interested in making my own pizza oven, this video helped me a lot! Kudos!
You are very welcome! Thanks for the encouragement!
Excellent video! Thanks
You are welcome!
Thank you for the information my Friend
You're welcome!
Thank you, I'll put on my list to watch it again.
Thanks!
Really thank you for such a quality content with experment.
Thank you!
Wow, what a well made informative video! Thank you
You're very welcome!
That was an eye opener!
Thanks Peter!
great video! love the amount of nerd in this! you've sold yourself some fire bricks (metaphorically speaking)!
Haha thankyou!
Very informative, thank you
You're most welcome!
very important informational video !!! thank you very very much.
You're very welcome! Glad you got something out of it!
Thank you very much.. really nice job.this video helps me lot
You are welcome!
Well done brother! 🙏🏻
Thankyou!
Excellent video!
Thank you very much!
Thank you. Very informative! I bought red concrete bricks for my small outdoor oven, i hope it will do ok. And as you said, i will slowly acclimate the hot temperature to them before i cook them pizzas😃
See how you go DJ, feel free to report back here in a few months with how it's all going!
Very informative!! Thanks.
Glad it was helpful!
@@TheFireBrickCo If i wanted to build a ghetto version with old red bricks, I was thinking 100 year old reds, I've got a stack of them, plus cash seems to be a bit tight these days with this corona thing, would you guys do just a floor and flue kit? If so, how much? Cheers
Thank you for sharing
Thanks for watching!
Well done mate 👍🏻
Thanks Kazuha!
Excellent. This was very helpful for me to make the right decisions for my design of an oven I am going to build. Btw, lol, I like the sounds in this video.
Ha! Thanks David!
Thank you very much for this video
No problems, you're most welcome!
Very informative!
Glad it was helpful!
Thanks, very usefull video
Glad it was helpful!
Nice, I was just about to buy the red ones to make my pizza oven. Thanks a lot.
No problems! It's not that pressed red bricks won't work, they'll just slowly break down over time.
excellent experiment sir,
Thank you! Cheers!
Great jo...very scientific.
Thanks Chintan!
Nice vid Ben. 🍕 Ovens 👍!
Thankyou!!
I built an Alan Scott design (the Bread Builders book) wood-fired oven 10+ years ago. I would guess I have fired it more than 100 times since. The hearth is fire brick but the dome and end walls are used red brick (probably 80-100 year old brick). I take 3 1/2 hours to fire to 800F 1" below the hearth or dome surface), cook the pizzas over the next hour and then it takes 24 hours to cool back to ambient. I have not had any spalling of the dome or end walls. The red bricks may have cracked, but nothing has fallen on the pizza or the hearth. I wonder if the slower cycle times accounts for the lack of spalling. Also the Alan Scott Design has a cast concrete cap over the dome to hold everything in place.
I don't know of any pizza oven that cycles as quickly as your test rig. I realize that a 24 hour test would take a long time to complete multiple iterations but your current test seems to not mimic reality.
A topic I would like to see explored is thermal mass. The Alan Scott design is really a high mass bread oven designed for multiple bakes in succession. Pizza does not need that thermal mass. It just needs high heat on the hearth to cook the bottom and the fire to cook the top. As a consequence of the thermal mass, I use a lot of wood to heat up the oven .
Hi Jim - thankyou for the very well thought out response, much appreciated! The test rig was designed not to try to mimic the exact conditions experienced by a brick in a wood fired oven, but to show the effects of thermal shock on different materials.
Your longer cycle time is definitely going to be protecting the bricks from severe thermal shock - I'd be interested to hear your firing method and whether you build the fire in one location inside the oven, and how that particular area is faring compared to the rest of it.
Your heat up time at 3.5 hours is fairly long, but it's the cool-down time that has me interested - 24 hours is very short, is that with a door sealing the oven opening? I think that Alan Scott has done a great deal of good for the wood fired oven community, however his design doesn't incorporate much insulation, and focuses on thermal mass. The thing is, you can have BOTH. If you had the same thermal mass that you have in your oven, properly insulated, it should take around 3 days to cool down, and even then it would be well above ambient. Any suggestions of an experiment/video that we could put together around the Thermal Mass topic?
@@TheFireBrickCo My ASD oven has the following features: Hearth is fire brick laying on top of 3 1/2" of reinforced concrete slab that is thermally broken from the slab support walls. Under the concrete is 5 1/2" poured in place perlite/pumice and cement insulation ; Dome is one layer of red bricks with a 3 1/2" poured in place reinforced concrete cap with 6-10" of perlite/pumice insulation over that.
I start the fire at the door and push it back as the fire progresses so that by the 2 1/2 hour mark it is in the center of the dome (it is actually a barrel vault). At the 3 1/2 hour mark I rake out the embers all over the hearth and let it soak. I keep at least one piece of wood burning during this so that when i push all this to the back, I still have a fire. I add a couple of sticks of wood, at that point, swab the hearth with a wet rag on a stick and probably wait another 20 minute for things to even out. The first pizza is always a flat bread to test the heat (don't want to waste toppings). If it is too hot I wait some more, if not we are good to go. I think Alan Scott thought this oven took 5-6 hours to fire to get enough energy in the mass to cook 4-5 batches of bread.
i remember being on a forum before he died and he quit the forum due to exasperation with us pizza makers complaining about how long it took to heat up. His point was this is not a pizza oven, it is a bread oven. I think he said something like " if you want a pizza oven, get a 200l barrel, cut the end out, lay it on it side and build a fire". His point was you don't need the same thermal mass for just quick cooking pizzas.
I leave the door open for cool down. If I close the door (uninsulated) I am sure it wouldn't reach ambient for 48+ hours.
I buried 5 thermal couples in the masonry at the time of construction so I could learn how quickly it heats up. What I found is that even with my 3 1/2 hour firing, the concrete below the hearth and above the dome was barely 200F and continued to suck heat out of the bricks after I stopped firing. I" from the surface was 800F
The next one I build will be much less massive - maybe just bricks and some insulation.
i was hoping you could maybe show how quickly heat builds up (or not) in bricks. Some folks have wanted to used insulation bricks for their oven but miss the point that the retained heat in the bricks is actually helping cook the pizza.
I do like my hearth size -30" x 40". there is enough room in the back for the fire and room for a couple of Pizzas. It could be shorter than 40" - maybe 30x30 and do the same thing although working closer to the door is less convenient handling of the pizza.
I have been half tempted to build an oven that is fire brick with an insulated metal dome. Get the hearth hot and then rely on a good fire to radiate the heat off the metal dome to cook the top.
Enough for now
My is build the Same way, except I used the ones with 3 holes in it, filled with mortar. Used for about 2 years to cook pigs and lambs, no crumbling yet. Heart is fire brick
congratulations, a very clear and explanatory video! perfectly clear and very good to learn from those who know, thank you very much, again my sincere congratulations and thanks!!
Thanks to the advantages of virtuality, I am writing to you from Colombia, I had to thank you for your great pronunciation, for people who have another language as their mother tongue, it is much easier for us to understand when a person pronounces English so well, thank you very much that's why too
Oh thankyou Ricardo! My mother would be very pleased to hear that my pronunciation is on point!
Really enjoyed this demonstration. Will you be releasing studies on Brick mortar?
Hi Michael, it's definitely on the cards! We will be setting the rig up again soon...
the right mixture of sand and clay works very well....
I like your experiment way, great job👍🇮🇩
Thank you! Cheers!
In a way, this video alleviates my concern with using regular bricks to build a pizza oven, since I really don't think it would be used for more than 5 or 6 times a year. Thank you for the really helpful information.
No problems Chomp!
Great video! thanks for doing this - excellent demonstration. Just a question, will covering the front of the bricks with a centimetre or so of fire clay stop this rapid deterioration?
Good question Ryan - the issue with that will be that the fire clay wouldn't bond permanently to the brick, and would delaminate over time. Otherwise it would definitely make a difference, by reducing the severity of the thermal shock experienced by the brick.
@@TheFireBrickCo Good point, didnt think about delamination. Thanks for that :)
Excellent Presentation. About a question I didn't know I needed an answer to.
Hahaha, glad to hear it was helpful!
@@TheFireBrickCo Does it also apply to terracotta tiles.
I suspect Yes.
Thinking about a Pearlcrete Pizza Oven on top of an insulated j hook rocket stove.
Really informative vid, thanks.
Is it possible to use the bricks from storage heaters instead of fire bricks in a pizza oven? Could you test them like this to see?
I'm not certain but I had a feeling that storage heat bricks were very similar to fire bricks?
This is perfect! Next (if you guys do this again) should be testing different "species" of fire brick, i.e. refractory cement vs plaster-of-paris mix vs etc.
Thanks! Great idea!
Also maybe you could test bricks with different alumina. 30% 40% 50% alumina
I used red bricks for my forge and it worked well. It was a cool forge but after a couple uses some the bricks cracked. You probably when to use firebricks when making a forge if you don’t want to make one from a truck rotor, 1/4 or 6-8mm plate. Wield it in the shape of a box tapering down like maybe a 6x6in tapering down to a 4x4in. Or a 8x8in tapering down to a 4x4in. That is 20x20cm tapering down to a 10x10cm. Probably 3 1/2 inches deep or 8xm deep.
Sounds about right!
EXCELLENT VIDEO
Thank you very much!
@TheMelbourneFireBrickCo
Do you have any videos on hiw to make fire bricks. Ive watched a few and they all seem to be different and seeing as though youve done testing i thought maybe youd know a good recipe
Cracking is all about the COE alumina and fire clay have relatively very little movement within their thermal expansion whereas red brick have lots of iron which is less dense and Ferris non- Crystal Inn
Cool Geek
Hahaha I'll take that
Thanks for the informative video, very cool testing setup! I'm building an oven but am more worried about food safety of the materials, do you know if there are any health concerns for heating standard red brick vs fire bricks to a high temp?
Hi Arthur - great question! Our fire bricks are made from fireclay, which is a naturally occurring material with a high level of alumina. I don't believe there would be any difference between a pressed red brick and a fire brick in terms of preparing food on either surface, providing the pressed red brick is unglazed (which would be an issue)
@@TheFireBrickCo
Isn't aluminum bad for our health ?
@@maxgarbani6644 well it is probably bad if you eat it, but not if it is inside the bricks.
Nice Demo Mate. I have a Wood fire BBQ (for a better word) which I built from ordinary bricks I had laying around. Its been in service for over 5 years but it only gets used 3 times a year as I have a Normal gas BBQ.
I had never thought about a house Fire place.I guess they do last a while. I can recall some old Pubs with fires every night. Blood Fire heats up the whole Pub!
Thanks Covis!
Great video. Do you use your fire brick for floor also or do you have a recommendation on a floor refractory for a home wood fired oven?
We definitely use them for the floor - the floor cops thermal shock just as badly as the dome so you want to use the right material there too.
Awesome. Love from India
Thankyou!
Well done! Thanks for the video excellent information. P.S. The Higher content of Alumina in the firebrick the better quality the fire brick will be. It's also more expensive the fire brick but will handle more heat!
Thanks!! You are correct on both counts - however they will also be more thermally conductive which can be a problem for the oven floor (burning the crust). We find the 38% mark is the sweet spot - high enough for great quality brick, but low enough that they aren't going to burn a pizza the second it hits the oven floor
Your content is why I love RUclips very interesting and informative. Thanks for your time to make these clips.
Glad you like them! Thanks David!
Very interesting video. Just curious, how much better would normal brick hold up in an open fire pit as opposed to an enclosed oven? Thanks
Now THERE is a good question - firepits don't get nearly as hot as a wood fired oven as they're open, so you have fresh, cold air coming in over the bricks cooling them down somewhat. That's for the sides at least. For the base, it's still going to get very hot beneath the fire. The downside of firebricks in that application is that they are porous, so they'll soak up rainwater if left exposed.
Hi, do you have recommendation on what to use for the mortar? Would bog standard Portland cement do? Cheers
Hi, great question! Definitely don't just use normal Portland Cement based mortar - it breaks down at around 350C which you are definitely going to exceed. You'll need to find some Refractory Mortar in your region
Good to know that my pop up red brick oven won’t explode. Thanks for the informative content.
No problem 👍
Care to share how you built it?
@@SIFUSAYSRELAX there’s a yt video search pop up wood fire brick oven
You got A nice pizza oven there Mate!
I think the pizza will be done faster in Your Nerd oven then in A Neapolitan one!
BTW what are the bricks in Your Nerd Furnace?
Hi Kees - haha I think those pizzas would burn instantly! The bricks lining the furnace are an insulating firebrick - very soft and porous but incredible insulators.
Thanks so much for this info Ben! I've been scouring the internet for fire bricks in South Africa and they are scarce as well as extremely expensive.
When using pressed red clay bricks for an oven, should I preferably use refractory cement as mortar?
I'm thinking that standard cement/mortar will crack and break long before the bricks do.
And to your knowledge, would clay paving bricks be a better choice than the pressed red bricks?
No problems! Without knowing a whole lot about the pavers I couldn't say for sure whether they would be any better than the pressed reds you have available. Definitely use refractory mortar if you can get your hands on some!
Thank you, Thumbs Up!! Would you mind giving me your opinion on what sort of problems I'll encounter if my contracter used the SAKRETE High Heat Mortar with actual "Fire Brick" but instead of just using the mortar underneath the brick, he used it underneath and then made grout lines instead of placing the brick next to each other. Can I use that a my cooking surface? Or do I have either replace the whole thing by putting another layer of fire brick. hope this question make sense
Hi Yuri - it does make sense; your oven floor has mortar joints in it rather than being firebricks pushed hard against each other. It should pose a huge issue - I would want the mortar to be recessed slightly below the brick surface so that you don't end up getting any into your food though
Hi there, I was wondering if you guys stock fire bricks suitable for building a DIY forge? I'm a local in melbourne myself! Thanks
We do, but in these crazy days we aren't able to ship them out or have customers visit! Sighs.
Miners use thermal shock to bore in hard rock..A fire is built against the rock face, then when it is hot water is thrown on it. The thermal shock shatters the rock nicely..
That is a TERRIFIC illustration of it!
Would you say it would be a longer-lasting design to use red brick on the sides of the over and use fire brick where the wood will burn and the platform you will cook the food on? Or would the bricks on the side also have issues the heat change? Fire brick is 3-4 times as expensive which is why many people stay away from it and use red brick and then pavers for the shelves in a tier oven build.
Unfortunately the bricks on that make up the oven walls will experience a great deal of thermal shock too
Really cool physics lesson in practice. Thank you so much for giving a demonstration of the real meaning red bricks are not as strong as fire bricks. I guess 99% of us all thought they could explode ore not handle heat at all ! But that is not the truth :-)
Thanks!
Any idea what kind of bricks 🧱 do we need to used for fire oven?
Thanks 🙏
We recommend using fire bricks for a wood fired oven, as you'll see in the video 😊
So, you ran your test through 240 cycles. And as you mention, in fireplaces the spalling is in the hottest areas, not on the surface of all the bricks. I'm assuming this would be the same in a pizza/bread oven - so in the dome directly above the fire and the floor directly below it. Less spalling (maybe) in and above the actual cooking area. My concern has always been about the comments saying "regular" bricks will explode. You say that's not gonna happen. If I fired it up a few times per month, regular bricks seem like they ought to last a good while before I have to worry about getting brick dust and bits into my food! Thank you so much for this video!
No worries! Just take you firings very slowly - don't use our Fire and Forget method that's for sure!
Really very informative, clear and useful. Can't add to comments of Subbu below. Thank you.
Thanks Maxine!
Another consideration is that lighter bricks have better insulating qualities. This is important if one is building a furnace for metal casting, pottery, etc.
Yep for sure! For a wood fired oven you would want a dense firebrick to store heat in.
这实验牛批！推荐给了建筑学院的师弟。哈哈哈
Thank you, I think!
I wonder if you may have been too kind on the bricks by testing only a thin sliver, which will heat up very quickly but fairly uniformly. A whole brick exposed to rapid temperature cycling on just one surface would presumably see greater stresses from differential expansion of surface and interior, leading to more spalling of the surface. Did you also test whole bricks? (Great video!)
That is a good point right there Tim - We haven't done further testing at this stage but I think you are likely spot on - a full brick would be stone cold in the center while the hot face has reached 300C, leading to much greater thermal stresses. Id say we would actually get bits of brick popping off if we tried it in the test furnace!
What sort of disclaimer do you provide for ovens dropping grit onto the pizza? I've thought of starting a wood fired pizza shop but what if a customer bites into tiny fragments of firebrick?
That's a good question - it's not something that we have ever heard of happening with one of our ovens thankfully! I'm guessing that most restaurants would need to have some kind of public liability insurance cover?
Not bad mate, not bad at all. Speaking here as a professional lab rat and amateur pizza oven builder.
I would only do two things different. One I would find some way of not heating your red bricks to dull red at one end and dark at the other. Dull red is, what, 700C? Whereas the other end of the brick is not red at all. So at least 200C temperature differential from one end to the other. That's a pretty big differential setting up internal stresses.
Perhaps a plate in your furnace so the flame can't impinge directly on the brick?
Secondly, I would limit the max temperature to around 550-600C.
Several reasons.
One: high alumina firebrick is usually weaker at the lower temps than it is at say 1200C Naturally, I can't lay me hands on the appropriate phase diagram right now. (Spewing I didn't pinch a copy of the company refractory manual when I retired.)
Two: its a fairer test of the capacity of any brick to run it to the temperatures it would actually see in service.
2 minutes up and down is pretty radical. My oven is made form fired clay pavers - it generally gets 2 hours up, held at pizza temps for a couple hours, then overnight cool off leaving the fire to burn down with the door on it. It has one cracked brick in the arch (cracked right through like I'd sliced it that way) and no visible spalling. It's ten years old.
Don't get me wrong - firebrick is definitely better, and I 100% agree with your reasons for that.
Damn, I'd love to get my hands on your test rig. I'd really like to compare homebrew mortar with alumina based mortar/castables and CAC based cements. Because, in a pizza oven, I can't see the alumina based castables ever reaching the 1100C needed to make mullite.
Thankyou Mick! I'm definitely no scientist - I would agree with almost everything you said there; it would be really good to be able to do a longer term test with a slower heat ramping time and cool down time to give a more accurate result.
On what you said about the differential thermal stresses - I think that's one of the things that fire bricks are designed to handle better than the pressed bricks, so in a way it's a good representation of that. The thermal shock test rigs that I've seen in refractory labs (which are SO DARN COOL) actually take the samples and lower them into a furnace - so the exposed end of the brick experiences a roughly uniform temperature (unlike our furnace with no baffle - that's an excellent idea). However I think even with a baffle we would still set up a significant differential between the hot end of the sample and the opposite end which is secured in the holder, so there would still be a really significant temperature differential in the sample, just across a different section of the brick.
I reckon I will set up the rig again some day - I have so many things I want to test! But it would be good to set up a better rig - I'm thinking of modifying an electric kiln...
Very informative video. Now I’m wondering where the idea of exploding bricks comes from?
I'm sure in the right set of circumstances you could make a brick explode (say, a concrete brick that's soaked in water, if you got that really hot, really quickly you might get a steam explosion of some kind)
River rocks, and cinder blocks will fracture rapidly. River rocks ive seen/heard explode.
So to prevent red brick flaking, how slowly should it be heated? Would they flake if it was brought to temp over an hour?
Hi Jasper, to minimise spalling you would probably need to ramp them up over around 5 hours or more - the big bread ovens take several days, sometimes longer to get up to temperature.
building a oven.bristol blue engineering on outside then insoluton then fire bricks with 30mm of render on.blues ok to use?.
Hmmm I'll just re-word that to see if I understand you correctly. Firebrick as the hot face, followed by high temperature insulation (50mm of ceramic fibre blanket would be the ideal) then 30mm of render, with the 'bristol blue engineering' brick on the outside? If that's the approach then it sounds good.
What about the actual slab the pizza sits on what do you recommend. I've seen guys just use a patio stone which seems suspect to me... Unless there's mesh through it?
We use fire brick tiles for the floor of the pizza oven if that's what you're referring to?
How did you cut the samples so cleanly? Are they from the same bricks on the table?
Good question - diamond blade on a wet cutting brick saw. Yep they were cut from those very same bricks!
Firebricks, or bricks that's been harden by fire, got it
. . . What about the binding of the bricks when making an oven? Do I use cement? Or mortar? Or something that's specialized in heat resistant and thermal shock?
Hmmm not quite - technically almost all bricks are 'hardened by fire' - a fire brick is made with a very different type of clay to most building bricks. You would need to use refractory mortar to lay the bricks for a wood fired oven - check out our building series for more info