sand under firebricks?

[david s]

Re: sand under firebricks?

Hi
Use the fireclay.... its fired and will not soak up moisture and return to soft clay. It still has the properties of clay which allows slip betwwen the particles and helps in the expantion/contraction during heating/cooling of a WFO. I have just found this out and am thankfully that I did use fireclay to set my hearth bricks and as a component of the home brew fireproof cement.

Regards Dave

Dave,
I think you are confusing fireclay with grog or chamotte, which is crushed and fired clay. Fireclay (unfired) will certainly turn back into mud if it gets wet enough.
Any unfired clay will not become permanent until it reaches the quartz inversion stage (573 C) too high for a WFO.
Dave

[Les]

Re: sand under firebricks?

Some clay can fire at low temps (that would be a bad thing). I am sure someone here has measured the temps below the hearth bricks. I know the dome will go off the chart. What temp is recommended to fire your clay?

[cobblerdave]

Re: sand under firebricks?

Hi
Use the fireclay.... its fired and will not soak up moisture and return to soft clay. It still has the properties of clay which allows slip betwwen the particles and helps in the expantion/contraction during heating/cooling of a WFO. I have just found this out and am thankfully that I did use fireclay to set my hearth bricks and as a component of the home brew fireproof cement.

Regards Dave

[Poetryart]

Re: sand under firebricks?

This may sound nuts, but... I am a sculptor and have lots of bags of clay around, including some that is too dry to work with. Traditional oven says I can use that, let it dry and crush to a powder to be my fire clay. Do you see any problem with that? It sounds so logical to me, I guess that's what makes it sound nuts. I really like your oven, cristo, good job. Now that you've had it 4years, how often would you say you use it? I'm curious if the novelty will wear off, or if it becomes even more of an obsession over time! My husband and I are already drooling over the possibilities...

[christo]

Re: sand under firebricks?

I put dried fire clay under mine... wow 4 years ago. And the bricks are still quite flat. It seemed to take up for the irregularity in the fire brick. I was lucky, my bricks were quite uniform to begin with.

[Poetryart]

We're pouring cement for the hearth this afternoon on top of concrete backer board, I've ordered FB board from Forno which should be here soon. I'm seeing different options of putting a thin layer of sand between the FB board and the firebricks versus using a sticky mortar. Which is best? I'd like to be able to remove damaged bricks over time and think the mortar wouldn't allow me to do that. We're planning an igloo with 2 layers of FB Blanket and concrete. Do I need to use refractory concrete on this? or will regular work?
Will post photos if I can figure out how...
Thanks - I'm really excited about this and am so grateful to the Forno website!