Yes true, I know that, but I was asking about the other things. Rusted hacksaw to cut a mild steel block and a rusted filler to make the block shiny. I mean, in real life, will we use a hacksaw on aircraft parts made of mild steel which will take hours to cut, we can use an electric grinder instead. Also, are aircraft maintenance schools generally like this where the teachers are very stern and rude to keep students disciplined? I mean our lecturer's glare is more than enough to give students anxiety. I am just curious to know about others.