Relex

Hello there! I'm currently planning to build myself a forge and have trouble to find a rigidizer, I live in germany and every translation I tried didn't give me good results, so I wanted to ask you if you have any recommodations for what brand I should use. I plan to cover my 1400°C ceramic wool with 1600°C fireproof cement but want to safe my lungs incase it cracks. Thanks in advance!