Low alumina content firebricks - are these ok?

[BrickOvenMike]

The folks at my local brickyard, as many of you have indicated in other posts, were almost completely oblivious to the differences between the different types of firebricks (low-medium-high duty). However, they were able to provide me with an MSDS-type information sheet ... WOOT

Anyways, these bricks are comprised of only 16% Al2O3 (alumina?), and I have read that the target alumina amount should be closer to 30%. Can anyone tell me if these bricks will work well in my hearth and dome?

Thank you!!
Mike

[Matt_Blacka]

Re: Low alumina content firebricks - are these ok?

Hi Mike,

Did you ever get an answer to this question. I have the opportunity to pick some bricks up that have about 25% Alumina, which is still a fair bit lower than the recommended 36%.

Matt

[BrickOvenMike]

Re: Low alumina content firebricks - are these ok?

Nah, I tend to ask questions on this forum that no one wants to / is able to answer ... Since posting this question, I have finished my oven with the lower alumina-content firebricks (dome and hearth) and they have worked fantastically! The oven takes a long time to heat up, but stays hot all that day and night.

[GianniFocaccia]

Re: Low alumina content firebricks - are these ok?

Mike,
Got any pics of your oven?
John

[Matt_Blacka]

Re: Low alumina content firebricks - are these ok?

Hi Mike,

Thanks for your reply. Everywhere I look I seem to find mixed answers regarding the need for 30+% Alumina in oven bricks.

Glad yours worked out well.

Matt

[Johnny the oven man]

Re: Low alumina content firebricks - are these ok?

Matt, there was a brick company in bacchus marsh that no longer makes bricks, and they had been making mostly 26% bricks for 100 years, all suitable for WFO's. They even made a dense brick in 18% which would have been ideal. Go with the bricks mate.

[BrickOvenMike]

Re: Low alumina content firebricks - are these ok?

Three pics attached...

[Matt_Blacka]

Re: Low alumina content firebricks - are these ok?

Thanks John. These are the bricks I'm talking about.

[Johnny the oven man]

Re: Low alumina content firebricks - are these ok?

Thanks John. These are the bricks I'm talking about.

Cant see any pics Matt. What branding have they got? Darley? Sth yarra?

[GianniFocaccia]

Re: Low alumina content firebricks - are these ok?

Very nice, Mike. Hopefully, your story will convince doubters to build with whatever firebrick is available. An oven built with 'less-than-ideal' firebricks is better than no oven at all.

[BrickOvenMike]

Re: Low alumina content firebricks - are these ok?

Agreed, I'm no expert (this oven is the first masonry work I've ever done), but I've been very pleased with the performance of my firebricks.

My oven takes between 3-4 hours to heat up (My construction is 4in firebrick + 4in concrete + 4in perlite), and holds the heat well enough to cook at least 3 batches of bread at a time, probably more, although I've never tried more than 2 batches at a time.

Pizza cooking is even better starting out at about 900F (500C) ... last month we hosted a large party and I cooked just over 100 pizzas in 2-1/2 hours ... the oven dropped from about 850F to just over 500F in that time, and TONS of thermal energy was transferred to all those pizzas ...

Once again, I'm using firebricks with only 16% alumina content, and they work great!

Thanks guys for all the advice and feedback you offer on this site!

[old wanderer]

Re: Low alumina content firebricks - are these ok?

Last year I bought 350 white used fire bricks from a kiln where they used to process coke. The I got sick and had an operation. Last week the person I bought them from called me and said...."I know I said you could keep them at my house until you wanted them, but it has been over a year....(I drove 60 miles Saturday, and loaded all 350 bricks into my PU).

I have been trying to find our the Alumina content of these, but like was pointed out, quit procrastinating and get the oven built.

The support base is set, the 1st vermiculite/cement 2" layer is poured, now ready to pour the 6" support slab for the real oven (as soon as it stops raining).

I found a retired mason that was selling his commercial quality tile/brick saw with a $300 diamond blade for the price of a new blade, so will take a few of the bricks with me when I go to pick it up on Tuesday, maybe he will know.

I am also shopping for some flag stone to cover the outside of the whole wretched mess, when I get it up.