Kevin I think they sell a more specific ceramic wool rigidizer, I bought some called Mr Volcano. It’s best to also coat the wool with refractory cement and/or some 100HT refractory.
100HT is infrared reflective so it’s even better than just rockwool or ceramic wool.
Cody - I think you and I are reading some of the same web pages. Good stuff to be found poking around DIY forge websites and videos
There are definitely better rigidizers than water glass but it’s an easy to source option. I like water glass as a thinly disbursed binder for cast perlite/vermiculite hard insulation. That wouldn’t be a good material to surround the heart of a gasifier directly but it’s a nice/cheap/light bulk insulation that can handle second layer type temperatures.
My head design for a stationary gasifier is HT100 faced fire brick surrounded by said perlite/water glass cast insulation, all inside a metal enclosure. Should be skin safe heat on the outside and hot as heck on the inside.
OK thanks cody- i may try some 100 HT refactory–How thick could it be put on a ceramic fire tube with out falling off–or maybe some mr vocano first to ridgenize the wool- then how thick will the 100TH refractory stay on- or do it need be put on in coats.? THANKS guys on the replies.