Having seen it done on a large motor
yacht that I worked on, I can say it is a silly simple operation. It is almost identical to doing a plaster cast on a broken arm or leg. I am not sure if the wet materiel is the same as plaster, but the method is the same. It just takes wrapping and lots of runny plaster, and drop clothes so you dont get it all over the place. It normally is done only before the water
injection into the exhaust, but would not hurt further down if the exhaust is metal. I think it would crack off of any kind of rubber or flex pipe. I hope this helps. _____Grant.