Are these firebricks the right weight?

[Nick]

We're all set to start building the oven floor. I decided to double check our red firebricks and compare them to the yellow ones I bought for another project years ago.

The red firebricks are 8 5/8 " by 4" and weigh 6.3 pounds apiece.

The yellow firebricks are slightly larger-- 8 7/8" by 4 3/8" and weigh 7.5 pounds.

Does the weight of the red firebricks sound right? Low duty? Medium duty?

Thanks very much!

P.S. I am taking photos of my oven every step of the way. I'm in the middle of "work stuff" and "life stuff" right now, so posting them is beyond my abilities.

I really appreciate all the support and advice that's on this forum!

--DB

[dmun]

Sounds about right: The weight thing is to warn people off the kind of insulating firebricks used in ceramic kilns, which would weigh under two pounds. I believe that you'd need a scientific scale to determine the alumina content in brick - they would all look the same to a postal scale.

[Nick]

Thanks very much. That's a big relief!

I have another question, which I'll post separately, because it's about the insulfrax blanket. The supplier I've called has it in 2" x 24" x 12.5' in 3 weights--4 lb, 6 lb, and 8 lb. I'm inclined to go with the heaviest, but maybe that's overkill.

I'll post this question separately.

DB