Question about fire brick material

[Gulf]

alexlea88

I see that you have posted your question here on another thread with a little more detail about the hardness of the brick that you have.

I've been able to pick up a few hundred refractory bricks from a steel fabricators, but wanted to check that they are suitable for a pizza oven. I'm pretty sure they're high alumina; white colour with small flint-like flecks inside. Takes ages to split with a bolster. I was planning on following JR's method and only cutting part way. Is there anything else I need to consider? I'm just cautious about building an oven with some random bricks I got from industry! At the same time, they might give me an awesome oven! Any thoughts?

Being difficult to cut with a bolster is a good thing. That usually means that the density and weight is higher than standard brick.

Above you linked Zircon as the manufacturer. Since alumina content usually relates to hardness, I believe that ZR-30 is what you have on hand. Again, I'm not familiar with this manufacturer's brick. I'm bumping this thread in case someone on this forum will see it and can help.

You may also want to go on some of the UK's wood fired oven forums to post your question. If so, my advice is to start a new topic on that forum. Include all the information about that brick on that one single thread.

[Gulf]

Here is a pic of an oven that was started on this forum. The builder decided to start over with clay firebrick. It was first thought that the brick in this pic were victims of freeze thaw. It turned out that they were calcium silicate firebrick.

[Gulf]

Hi Alexia,

Welcome to the forum. I edited your post to remove the direct commercial link. I replaced it with the spec sheet from that site which shows the 4 types this manufacturer sells. First, you should attempt to find out which type you have as they are vastly different in recommended use. My understanding of looking at their site is that the brick is not a clay based brick as I am familiar with. I believe that these are silica based. The only silica brick that I have on hand is fairly light weight and very easily abraded. I'm not comfortable with recommending them for a WFO. Hopefully someone with more experience with that type brick will chime in.

[alexlea88]

Hi all. Not sure if this is the correct thread to post, but I've picked up a couple of hundred industrial refractory firebricks from a steel fabricators and was wondering if they would be suitable for making my oven dome. They are a similar size and colour to the ones in the link below. I've tried splitting them with a bolster and inside they have small grey particles. Otherwise, clean and in good uniform condition.

Zircon Bricks
Item/Index		ZR-30	ZR-50	ZR-55	ZR-60	ZR-62
Al2O3 %		42	10	6	4	–
SiO2		20	34	35	30	34
ZrO2		30	50	55	60	62
Bulk Density (g/cm3)		≥3.10	≥3.30	≥3.45	≥3.50	≥3.60
Apparent Porosity %		≤21	≤20	≤20	≤21	≤20
Compressive Strength (kg/cm2)		≥500	≥400	≥500	≥500	≥500
Refractoriness Under Load ℃ (T2)		＞1500	＞1450	＞1500	＞1600	＞1550
Expansion at 1000℃ (%)		0.6~0.8	0.4~0.6	0.4~0.6	0.4~0.6	0.4~0.6
Thermal Conductivity	500℃	1.7	1.4	1.3	1.2	1.2
1000℃	1.8	1.6	1.5	1.5	1.5
Application		Glass Furnace	Nozzle Seat	Ladle	Ladle	Ladle Glass Furnace

Not sure if I'm being overly cautious, but given I've no idea what they've been used for originally, probably not best to start building a pizza oven out of them! They also sound like they won't heat up as well as standard fire/ clay bricks.

Any thoughts/ suggestions?

[Gulf]

Changed my mind. Going to sell bricks and drink beer

Deleting all comments just means no lessons learned if this brick is suitable for a wood fired oven. At least you may be able to purpose them for a fire pit as you mentioned in your edited OP.

[Gulf]

Yes, the heavy weight is a good thing for comparison if they are dry. Breaking easily when dropped concerns me though.
can you do a little more of a background check? I would inquire about which kiln from which that they were “left overs”. If it was a commercial kiln, doing a little PI work may may help you find the exact specifications and the manufacturer.

[Gulf]

It is not unusual to find different color fragments in the lower duty firebrick. In those it is common to mix crushed firebrick (grog) in with the binding clays. That is a way to recycle the breakage from previous runs. A super duty brick will usually be made totally from pristine clays. In those the color will be a more uniform. The binding clay is a little darker than what I am familiar with, though I do have some old firebrick on hand that do have some grog mixed in that does match the binding clay in your pic.

To break a super duty brick such as shown is very difficult. So, I doubt that his is a super duty firebrick. That's a good thing imo. I would be curious to know how difficult this brick is to abrade and break with a brick set (bolster)?

[UtahBeehiver]

Post a pic. If from a furnace build they are most likely high or super duty. I used super duty in my build but they are really hard on diamond wet blades so if you can use them where minimum cuts are need, IE floor then it is a good option.

[Idresu]

Changed my mind. Going to sell bricks and drink beer