D70 fire brick

[bisland9]

i have located some free used firebrick. they are 4.5 x 9 x 3 and have d 70 embossed on them. does anybody know what this means? also they have been outside uncovered for 15 years. i live in central canada and can get cold -30 f. to +100 f. does anyone know if they are they worth using?

thanks
bernie

[jpar]

I think you have a duralite 70 firbrick manufactured by Chicago Firebrick - no longer in business. This is a 70 % alumina brick that is around 160 pcf. THese brick will take a long time to heat up, and a long time to cool down

[dmun]

Nothing beats free. These are high-duty expensive bricks, and I wouldn't advise anyone to go out and buy them, but they will work fine. They are just a little harder to cut than the ones from the brickyard.

Good luck with your project - keep us posted.

[bisland9]

thanks for the speedy replies. i have completed the hearth slab and hope to start on the brick hearth next month. i bought new low duty firebrick for the hearth and i think i will use the D 70 for the rest of the oven. thanks again for your help.

bernie