Old red clay solids as firebrick alternative
Red Clay Bricks
Substitute for firebricks can be old red clay solid bricks. In ovens these alternative red clay bricks will heat up, cool down, cook, re fire, absorb conduct store and hold the heat from wood fire and perform the same way as proper refractory firebricks do. If you can not locate fire bricks where you are or for any reason obtain them, Red Clay Bricks will perform much the same way in wood fire temperature levels and can be used instead.
How do I see it’s the right alternative for firebricks?
The replacement bricks must be of this type, old solids. Clay body is the same on the brick’s inside as it is on the outside. Break or cut one of the bricks you find in half to see what’s in the middle. New products are made out of cheap clay bodies whilst only on the outside a decorative clay slip is applied and then the bricks are fired in kiln - you couldn’t use bricks like that. The right alternate also shouldn’t be burnt, if you saw too much black-carbon color in the center don’t use such brick - it would be either over fired and brittle or made out of lesser quality clay. But a few little burnt spots will be fine. 
Working with red clay solid bricks is equivalent to work with refractory firebricks, all matters remain the same only bricks are different.
Where to find these old red solid bricks?
Look around in demolition yards for instance they often stock these red clay bricks. Read advertisements in papers, people very often sell for fraction of price or giveaway exactly this type of old bricks, and other great building material left over from other projects or from cleaning up. There are always few firebrick replacements to be seen here you just have to watch it. You can buy 200 of red clay bricks even for 20 or 30 bucks in total and have lucky day. By the way these old bricks are easy to clean with hammer and brush because in the past brickies didn’t add much cement into mortar if any. Tables with firebricks physical properties.
July 9th, 2008 at 1:56 am
Firebricks are costlier too.
October 1st, 2008 at 2:50 am
There is nothing better than a pizza made in a wood oven, nice tips. Thanks for sharing.
November 2nd, 2008 at 7:23 am
This is a great idea. Not only are you using quality bricks, but you are able to used recycled materials.
pays to live green’s last blog post: Maryland Environmental News: October 2008
November 6th, 2008 at 3:18 am
I absolutely love pizza, but only the best pizza’s come from a wood oven, there is just something about it that gives the pizza its great taste.
November 20th, 2008 at 7:59 pm
I got these same old red clay solid bricks from our neighbor for nothing but there were that many I can build the whole oven structure out of them. The outer color of the walls and chimney will have real character. These house bricks certainly are very easy to clean from the old mortar just as you describe, it just simply pops off from the brick when touched. Still for the firing and cooking part on the oven I am ordering new firebricks from a supplier.