Go Back   Forno Bravo Forum: The Wood-Fired Oven Community > Regional Forums > Australia

Like Tree2Likes

LinkBack Thread Tools Display Modes
Old 07-21-2012, 06:17 PM
david s's Avatar
Il Pizzaiolo
Join Date: Mar 2007
Location: Townsville, Nth Queensland,Australia
Posts: 5,159
Default Re: Cheap fire bricks for sale!

Ok, but smashing a brick with a hammer will not tell you what it is made of or it's suitability. All it will do is give you an idea of its strength and therefore, probably it's degree of vitrification, neither of which will tell you if the brick is actually suitable.
Reply With Quote
Old 07-22-2012, 04:33 PM
Join Date: Jun 2008
Location: Melbourne Australia
Posts: 399
Default Re: Cheap fire bricks for sale!

Originally Posted by david s View Post
"Hit your planned bricks hard with a sledge hammer and check out the bits that it breaks into. If it crumbles into small pieces and sand/dust, forget them, but if they break into hard but larger pieces, then i would use them."

This is not a particularly good test for the refractory suitability of a brick. For example an insulating fire brick which is highly refractory crumbles easily and a standard firebrick is usually more crumbly than a solid red, although it way out performs it. Also the temperature the brick has been fired to is also not a suitable indicator of its refractory ability. It is the content of the materials in the brick that is the most important factor, things like high levels of silica, fluxes, and oxides are not good and they are extremely difficult for the layman to test.
David s, this is not quite right. One of our former leading firebrick manufacturers in Victoria, for over 100 years, had a firebrick of 75% Silica which would have been their largest selling firebrick for wood ovens over the last 20 years. it had just 21% Alumina, and just 4% oxides, and with a bulk density of 2000kg/m3 was absolutely perfect for this situation.This would be regarded as a low duty refractory brick. Yes firing temperature has a small effect on suitability, as normal house brick are fired at 1050c vs 1350c of refractory bricks. It really does not make a big difference though as you point out.
In most cases, a sold red brick is pressed during its manufacturing process, the same as ALL refractory bricks, this gives the density. Normal house bricks, yes the ones with holes in them, are wire-cut, they come out of an extruder similiar to say Toothpaste coming out its container, and then just cut into required sizes, with no pressing. This is part of the many factors that influance the suitability of refractory products.
brickie in oz likes this.

Last edited by Johnny the oven man; 07-23-2012 at 04:02 PM.
Reply With Quote
Old 07-23-2012, 01:32 PM
david s's Avatar
Il Pizzaiolo
Join Date: Mar 2007
Location: Townsville, Nth Queensland,Australia
Posts: 5,159
Default Re: Cheap fire bricks for sale!

OK, high proportions of silica in firebricks is undesirable for high temperature applications because it has a tendency to melt, in the presence of high levels of fluxes. As an example of this I once built a small experimental kiln out of mud bricks. At around 1100 C the inside of the kiln melted off in sheets. This is not a factor for a WFO application because it doesn't get hot enough. It was certainly not my intention to mislead anyone. I have removed the silica reference in my post.

Last edited by david s; 07-23-2012 at 02:20 PM.
Reply With Quote

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

Similar Threads
Thread Thread Starter Forum Replies Last Post
Oven (Floor - Wall - Dome) Fire Bricks Thickness?! southpaw Pompeii Oven Construction 11 03-12-2011 10:54 AM
Combining fire bricks azpizzanut Newbie Forum 2 02-15-2011 12:52 PM
High duty fire bricks Abear Getting Started 23 04-02-2010 10:43 AM
Cheap Fire bricks - Sydney Australia aj7877 Getting Started 11 09-26-2009 02:42 AM
New Fire Bricks with Cracks staestc Getting Started 8 11-03-2008 04:37 AM

All times are GMT -7. The time now is 04:46 PM.

Powered by vBulletin® Copyright ©2000 - 2015, Jelsoft Enterprises Ltd.
Search Engine Friendly URLs by vBSEO 3.6.0
2006/10 Forno Bravo, LLC