My Hartman Electric Furnace

[bruce.desertrat]

Thanks Rick,
I love your PDFs. Have you ever looked a foamed cement? One day if people ever stop bothering me I need to build a furnace and I have seen a few people using foamed cement sealed with Waterglass as the insulator with very good results. I like the fact that it is easy to work with and castable.
Here is a link to a foam generator that works well: http://pelagic.wavyhill.xsmail.com/

This sounds a lot like the RAAC concrete (currently starring in a huge scandal in Britain) https://en.wikipedia.org/wiki/Reinfo...rated_concrete