Firebricks - heavy dense fire clay bricks
Now days they are called heavy and dense Firebricks but old masters still call them fire clay bricks just because they are made of simple fireclay (which actually is the most ordinary mud.) Fire clay can be easily located out in the nature but it must containing the right refractory properties, suitable content ratio of silica and alumina. Some shops call these bricks fireplace bricks. They are used for instance for building cooking chamber in wood fired ovens, for creating fireplaces, all sorts of fire boxes and wood heaters’ lining, linings in a small or the hugest industrial furnaces, you name it. 
Fire clay bricks are very heavy/dense having low porosity and even on reheatings they can last for very/very long time.
Some may confuse them with insulating lightweight firebricks, those are used in different applications. Dense firebricks can be cut only with diamond wheel attached to high speed handheld angle grinders, on an ordinary building brick saw or sliding drop saw for cutting bricks. Fire bricks can be chopped in half easily by using brick chisel and a couple of hits with a heavier hammer. It is fun and quick but may you want to achieve precise nice cuts hire a trade machine or buy yourself at least small size grinder. Before cutting soak the brick in water by dipping it in a bucket of water or in a wheelbarrow if you had too many. Leave the bricks in that water for 5 minutes minimum. 
The cutting diamond wheel will last you for a long time if the firebricks are cut wet plus you won’t breath in any dust, and of course cutting gets a lot easier and faster!
What firebricks type to use?
When it comes to firebricks and dense refractory products composition content often Alumina (AL) ingredient is looked at which ranges ordinarily between 18% to 40% of alumina in modern product’s body. The percentage range is important for choosing the right product for the right temperature or Orton Cone but mainly if a high temps are applied. 
Alumina influences bulk density a lot and therefore also porosity, or if you like the weight of fire bricks. No need to apply above 26% in wood fired oven temperatures range but you can in case a low grade isn’t available to buy. Absolutely safely 18% AL amount firebricks can be used in wood ovens (you can melt and cast color metals in it too.) Furnace’s chamber build out of 18% will perform and last the same way as 30% alumina product.
Apart higher co$t, additionally, higher Alumina content grades make these bricks harder and brittle (more glossy if you like) making them absorb less steam e.g. from under pizza dough bases being cooked or bread dough. However one can get used to cooking in such oven fast.
Even though you can hear other words from a few suppliers who sell not locally manufactured product, conductivity and heat absorbing capacity is not influenced much at all by higher or lower alumina content. Higher grades won’t create magic temperature difference in cooking environment and vise versa. Main reasons for this are modern imports, one high alumina range suits all business and applications, less varieties to stock, higher markup and margin, those are the reasons if 18% to 26% brick isn’t sold by a store. Look for locally manufactured product, lower grades cost less to produce and they sell them for less. Where I buy refractory 26% AL firebricks costs $1.98 per one brick.
BTW mineral Graphite is lighter in weight by half if compared with Alumina or refractory bricks, and Graphite absorbs much more heat than firebricks (more reading about firebricks’ thermal conductivity and alternative for firebricks replacement.)
- 21% Alumina firebrick : 1850 tons Bulk density per Kg/m³ : Thermal Conductivity : 0.98 W/m.°K : 23-Orton 1620°C
- 24% Alumina firebrick : 1.925 tons Bulk density per Kg/m³ : Thermal Conductivity : 1.02 W/m.°K : 27-Orton 1640°C
- 27% Alumina firebrick : 2 tons Bulk density per Kg/m³ : Thermal Conductivity : 1.05 W/m.°K : 30-Orton 1670°C
- 33% Alumina firebrick : 2.15 tons Bulk density per Kg/m³ : Thermal Conductivity : 1.07 W/m.°K : 31 ½ -Orton 1700°C
- 38% Alumina firebrick : 2.2 tons Bulk density per Kg/m³ : Thermal Conductivity : 1.13 W/m.°K : 32 ½ -Orton 1720°C
- 40% Alumina firebrick : 2.25 tons Bulk density per Kg/m³ : Thermal Conductivity : 1.13 W/m.°K : 32 ½ -Orton 1720°C
TYPICAL TECHNICAL DATA - DENSE FIRE BRICKS
Physical Properties of Firebricks (23% alumina product)
- Bulk Density : 1915 Kg/m³
- Modulus of Rupture : 5 MPa
- Permanent Linear Change on reheating 5 hrs. @ 1400°C : -0.35%
- Cold Compressive Strength : 15 MPa
- Thermal Conductivity @ 750°C : 1.01 W/m.°K
- Apparent Porosity : 28%
Chemical Composition of Dense Firebrick - 23% Al grade
- Alumina : 23%
- Silica : 73%
- Ferric Oxide : 1.4%
- Accessory Oxides : 1.1%
- Titania : 1%
- Frits
Who is your firebrick or refractory supplier, do you have contact-s on them? And where are you located? Please leave your comments for others below…
May 28th, 2008 at 8:53 pm
My refractory supplier is ClayPave Pty. Ltd. located in Dinmore, Brisbane, Qld., on the way to Ipswich. They have distributors all around the country and Internationally.
It is large Australian manufacturer of refractory and clay products. ClayPave produces all grades of firebricks. Heat resistant mortars, ready mixed air-set in bucket, or fire clay in bags to mix your own refractory mortar at home - one bag is plenty for building 2 ovens. Best prices, delivered if needed.
Standard firebricks or splits: AUD$2 to $2.20 each
Fireclay: $25 per bag (large bag enough for 3 ovens)
Pre-mixed heat resistand mortar: $33 per bucket (1 needed)
Packed on the top of the palette with firebricks.
More info is here in the post about buying firebricks.
Web: claypave.com - look for their refractory resales in your area they are listed there, also overseas.
Phone: (07) 3282 1444
Email: claypave[at]claypave[dot]com
Address:
Factory & Sales Centre
Chum Street
Dinmore, Qld. 4303
June 1st, 2008 at 6:27 pm
Firebricks and refractory mortar in Perth, Western Australia:
Ian Mears, phone: 08 9434 9202 / mob: 0414 885 337
Address:
Mears Refractory Services pty. ltd.
Unit 3
9 Corokia Way
Bibra Lake
Perth, W.A. 6163
Western Australia
Ian is a nice bloke quite knowledgeable about ovens, very helpful, won’t mind to open the warehouse at odd hours when someone really needs when ran out of fire bricks. He hires brick saw -standing idle.
June 30th, 2008 at 8:07 am
Where is the closest place I can get refractory cement from as I live in York Western Australia.
July 1st, 2008 at 1:33 am
Did you check under ‘Refractories’ suppliers in phone book, or ‘Heat Resistant’ material?
I will ask Mark if he doesn’t know a place there around you. Have you located firebricks?
July 23rd, 2008 at 10:38 pm
Im still looking for a refractory supplier close to me in York.
If you find a supplier could you let me know as soon as possible.
July 24th, 2008 at 4:14 am
Hi Colin, Firebricks in WA are a hard thing to source but I do know of a place that does supply them, The Potters Market 56 Stockdale Rd O’Connor,Tel No 93376888.I cant tell you how much they charge per brick but I do know in comparrison to prices paid in other states from refractory suppliers direct they are a bit more expensive.When I built my oven 3 years ago I used normal solid bricks ” Austral Collie ” which is a cream solid .My oven is as good today as when I built it, Hope that helps Mark
July 24th, 2008 at 4:16 am
PS They also can supply your fireclay needs
July 24th, 2008 at 4:44 am
Hi Colin,
Yes the clay bricks Mark mentioned that he used for building his oven in Western Australia are almost identical to clay firebricks from Ipswich, they contain grog in the body as well. You can use them. Then there are solid clay bricks from Midlands somewhere, they are the same, can get the contact details if you needed. Maybe far from York?
July 24th, 2008 at 7:48 pm
Rado,
I hav ealready sourced some fire bricks,but Im more interested in getting some refractory cement for the fire bricks.
July 25th, 2008 at 7:35 am
WILL TRY Ian Mears in Bibra Lake
Thanks for all the info.
August 7th, 2008 at 9:16 pm
supplies in USA ; if you live in or near Maryland, you can get Mt. Savage “Medium Duty” fireclay bricks (43.1% alumina content) at Potomac Valley Brick and Supply Company. They come in yellow or red. I got mine at the Rockville, MD location (3 Derwood Circle), for $1.33/brick. They also sell the fireclay mortar in pre-mixed tubs. The bricks I bought there differ in dimensions (height) from the Australian ones (2.5 inches vs. 3 inches).
Thanks to Rado for all the help!!!
Charlie
August 10th, 2008 at 8:41 pm
I have looked locally in Western Australia - Perth:
Potter’s Market at $3.95 per brick;
Ian Mears at $3.88 per brick (smaller than normal 230×115x60);
Veolia Refractories $7.80 per brick;
Eastern States (prices including shipping cost to WA):
Darley Refractories at $6.57 per brick;
Claypave works at $4.77 per brick;
Shipping makes it very expensive to get firebricks to Perth unless you order larger quantity of course.
I have found someone who has a small quantity of leftover firebricks with 45% alumina content and is selling it for $0.50 per brick. I am a bit worried about the higher alumina content and its higher heat conductivity causing bread to burn at the bottom.
Fondu cement ($40) is much more expensive than Portland cement ($6), but as you say, if I want to use it -it is just a small slab. I believe I will need about 4 bags of cement.
August 10th, 2008 at 8:42 pm
Today I bought 7 bags of Vermiculite from “The Perlite & Vermiculite Factory” at address “Lot 802 Cutler Rd, Jandakot 6164, Western Australia” phone number 08 9417 8377. The price was $15 cash per 100L bag. This was very cheap compared to some Perth hydroponics shops who sell vermiculite in the 100L bag for $40.
Best regards
September 8th, 2008 at 8:01 pm
Suppliers in England. I live 22 miles from London.
Vermiculite from Travis Perkins very large bags £9.40
It is cheaper to go in a van on a cheap return ticket to France to buy the firebricks:
Firebricks in France - from Leroy Merlin near Calais only Euro 1.21 each
Firebricks from Ridgeons U.K. £2.47 + 17.5% vat
Building sand very large bag from Ridgeons £46.73 + vat
Ballast very large bag from Ridgeons £36.76 + vat
25Kg cement from Ridgeons £ 3.49 + vat
Fireclay 25Kg from Buildbase London £21.39
Lime 25KG from Ridgeons £ 7.86 + vat
If not used re-used or second-hand:
Marine plywood for boxing very large piece £ 14.00 locally
Small bricks from £0.30
Hollow concrete blocks from Ridgeons £1.88 + vat
My internal temperature reaches +500°C (932°F) and the outside walls and roof are +20°C (68°F) !
I hope this will help.
Regards
David
September 21st, 2008 at 10:09 pm
Tasmania - Firebricks and Vermiculite supply.
firebricks with 28% Alumina content
vermiculite (called shiralite) insulation
from:
East Tamar Maintenance Services Pty Ltd
Temco Road
BELL BAY
TAS. 7253
Australia
ph: 03 63822400
ph: 0418 139041
fax: 03 63822408
They also stock other refractories or refractory materials.
October 2nd, 2008 at 1:18 pm
Thanks for the great information Charlie. I live in Maryland and was looking into getting a brick oven. I will have to check out Potomac Valley Brick.
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