Heat Retention Properties of Bricks vs Homebrew?

[WoodywWun]

Learning as I go with my new build, I just wanted to compare the heat retention properties of homebrew as might be used in a cast dome with a decent fire-brick. I've gleaned that a good fire-brick will have heat retention properties of about 2.52 kJ/m³_K. I'm guessing that a homebrew casting mix will be a lot lower and has anyone any calculated value for it?

I suppose my question on from that is that if they do have significantly different heat retention properties (and this causes a problem), what effect will that have on the oven temperature build/loss and what steps, such as more insulation, might be needed on the dome to help rectify it?

Any thoughts on my musings would be helpful.

[Petter]

The type of mass does not matte at all. The mass (i. e in kg/lb) and insulation does regarding heat retention. Denser mass does however saturate a little faster but the difference is very little. Nothing to worry about. Denser mass also makes a thinner dome for the same weight.

[WoodywWun]

Thanks again Petter! Not worried...intrigued! It's the way my brain works.

Just so that I understand this....

• An object with a mass of 10Kg will store 10 times the heat of an object of 1Kg?
• The volume of either the 10Kg object or the 1Kg object is immaterial to its heat storage capacity?
• Two objects of the same mass will store the same amount of heat?
• Insulation will aid heat retention of any object.
• Does the material the object is made of influence how much heat it can store or is the mass the key factor?

Linking this to WFO ('cos this is where I'm going with this, unsurprisingly!), given that homebrew and fire bricks have different densities, what is the ratio of the thicknesses required for the two to get the same heat retention?