Firing > Firing / Kilns

Fire brick (hard)

(1/2) > >>

I am building a gas kiln and need hard fire bricks- so far the only local source (SF bay area) only sells super duty at over $3.50 per brick. I was hoping to find a cheaper source for atleast some of them, maybe the 1st layer of the base. But these dont actually seem any cheeper in the end- and i dont want to chance a disaster from wrong bricks.

Hi Daphne,

I saw a video that Simon Leach posted earlier this year in which he had put two or three hard bricks into his small cone 10 kiln - they sagged badly. He had purchased them at a home hardware store, and failed to read the temperature rating on the box before using them - they were rated for 2000F or so, as he discovered when he read the label. If you are able, my suggestion would be to purchase your bricks from a seller who knows what your needs are. Obviously shipping would be an issue if you are not close to a clay distributor. Having said that, if the bricks you are looking at are in fact rated for 3000F I think they would be fine in a cone 10 firing which goes to around 2350F.

Daphne, there are people who can speak to this with a great deal of authority, I'm not one. I have a little experience though and I'm happy to give my two cents. An advertised rating is worth looking at. Generally firebrick sold at big box stores for wood stoves, ovens, etc. is rated around 2000F. If a brick is advertised at 3000F you should be able to expect it to handle cone 10 or below easily. 2300F is kind of a cutoff point. Cone 6 (which is the range I play with) is around 2230F, cone 10 is around 2350F.

As for testing, I only know from sticking different bricks in a cone 10 firing. An ordinary house brick turned into a pile of melted goo. Low duty bricks (1800-2000F) started to glaze over and changed color. I inferred they were getting soft and squishy.


I was looking at bricks that are listed as 'firebricks' with a stated rating at 3000F. I wonder if there is some way to fact check or test?

Fireplaces don't get all that hot and temperature ratings of <2000F can be adequate to that job. That's why a lot of high-temp mortars are rated for about that temperature.
Unless you can get mfr specs that show higher ratings like 2300 or 2600, you're going all in on a dubious hand.


[0] Message Index

[#] Next page

Go to full version