Identifying bire bricks

[gecko]

I've just bicked up some fire bricks for a good price and am now a bit worried they may be heavy duty. The guy said they were ideal for a pizza oven but some people will say anything for a sale.

Is there a way to identify the different grades? They are standard house brick size, off white in colour and weigh a bit over 11 pounds. They are also very hard with sharp edges.

thanks in advance

[dmun]

Re: Identifying bire bricks

High duty bricks are harder. A standard fireplace grade firebrick will cut more easily than a common red brick, and a high duty one will be more difficult to cut. Other than that, without a test of the alumina content, it's hard to tell.

[nissanneill]

Re: Identifying bire bricks

Hi fire bricks are as dmun says very hard to cut, almost like cutting as block of steel.
They are also much much heavier than the low or medium fire brick.

Neill

[gecko]

Re: Identifying bire bricks

thnks for your replies guys. I haven't tried cutting them yet but have broken one with the bolster and hammer. It was pretty hard.

If they are high duty bricks can I still use them but maybe cut them thinner so they don't take so long to heeat up?

[nissanneill]

Re: Identifying bire bricks

Any brick cut thin will heat up quicker as there is less thermal mass. My understanding with medium and high heat bricks are that they will absorb more heat and get hotter for their specialty applications in foundries etc.
High duty bricks will get a lot hotter, probably hotter than you would want your oven to cook in but then again it will be up to you with experience to control and maintain your temperature level.

Neill

[gecko]

Re: Identifying bire bricks

well I've cut some of these and they are very hard so I guess they're high duty. Am I better off using these to make my oven or solid red house bricks. I've read that the reds take along time to heat up. Is this true of the high duty also

gecko

[nissanneill]

Re: Identifying bire bricks

Hi Gecko,
Not to my knowledge!
Solid red house bricks that have been fired at around 1100/1200˚C will heat up just as well and as quickly as any other brick. Because they are reasonably dark in colour, they will absorb the heat rather than reflect it. If the heat is not being absorbed by the bricks, where else apart from escaping out the door and up the chimney, can the heat go?
These bricks are plentiful, cheap (or even free), easier to cut and do not spawl like a lot of people believe. I know that there are bricks and there are bricks but Russell Jeavons and a local fire brick company sell more solid 4" pavers than firebricks for oven builds. My next 2 ovens will built using these bricks.

Neill

[gecko]

Re: Identifying bire bricks

thanks for the reply Neill,
So are you saying that the red house bricks would be better than the high duty fire bricks I have? I am a bit worried that the High duties will get too hot and/or take too long to heat up.

gecko

[christo]

Re: Identifying bire bricks

I think Neil is trying to give you info and alternatives.

The final judgement is yours - if you think the firebricks you have are workable - go for it. If you don't (as Niel says) many people have been successful with red brick.

I got lucky and had medium duty firebricks easily available - they cut like butter in the bricksaw and were a joy to work with. If I could not have found them - I'd would have gone with Niels sugesstion.

After having a functional oven for a year, I still have the best memories about building it - close seconds are the wonderful meals. Enjoy the build!!!

Christo

[gecko]

Re: Identifying bire bricks

Hi Christo,
I'm just trying to gather enough info to make the right decision and avoid ending up with an oven that is not going to work too well. I dont mind cutting the harder high duty bricks if they're going to do the job but will gladly but something else if they are unsuitable.