Originally Posted by bazza
Spraying CO2 onto red hot metal causes it to cool extremly rapidly this it will contract and can splinter sending sharrs of metal splitting off.
All comes from my RAF days with aircraft coming in with brake fires... funny what you remember from years ago.
Bazza - I am sure you are right - but its not a risk I have ever heard anyone mention about boat or car engine fires in the past so either its a risk we don't appreciate, or there is a subtle difference - like the temperature difference not being high enough. Certainly with boat engines its hard enough to get the CO2 where you need it - never mind get enough close enough to the "nozzle" that you would be getting much very cold.
Codprawn - you never cease to amaze me. I'm perfectly aware that Mg reacts with CO2 if it is hot enough, but since there is not much magnesium on my boat (given it doesn't really like water!) that isn't a major concern.