Posted by duncan webster on 18/12/2020 19:38:39:
I got some stuff from a firm advertising itself as 'refractory engineers'. They called it 'ceramic paper' It's about 3mm thick but has little strength
Ceramic paper is wonderful stuff! I use it as firebox insulation in my small stationary engines. It's a much better choice than asbestos. Available in various thicknesses from 1mm upwards.
Other materials to consider are Nomex and plumber's mat. You can get plumber's mat from B&Q or any good hardware store. Here at Генри Конструкторское Бюро we use Nomex to protect parachutes from the ejection charge on research rockets.