Comparing thermal conductivity of DIY "firebricks"
Channel: Ilusys Systems
Date: 2019-12-09

Reading some patents, the material used in hotplate is "Aerosil" which is pretty much basic fumed sillica. Further ceramic fibre is added to mix in 2-7% and optionally a opacifier, such as TiO2 in up to 30% This mix is then pressed to specific density, which will give it little bit of mechanical strength, without affecting thermal properties too much.
You can search microporous insulation.

Then what have I learned from this experiment?
 - I need a better thermocouple, lol
 - porous materials will have better insulating properties in "phononic channel"
 - there will be optimal pore size most likely
 - perhaps I should have done some initial tests on dry powders. This would give you better picture in "photonic channel". I have done some tests now and TiO2 seems to behave very nicely

Each sample was 15mm thick or 0.590551181in apart from pumice, that was thicker.

In the end I believe, that I can create very good mixture from easily acessible materials.