Are elves stupid ?

[Kuruharan]

Yes. They are also very stuck up.

Yeah i was thinking of the fall of Nargothrond.

Turin was able to survive that encounter because Glaurung was using Turin for his own amusement. He did not want to burn Turin to ash. The dwarf mask seems to have helped Turin avoid the dragon spell a bit (I suspect because he couldn't see the dragon's eyes as well and not because of some "magic" in the helmet.)

And as i said earlyer thy saw how well the dwarves armour worked (compared to others) then why not try to copy it ?

Well, actually, a lot of the armor the elves wore was made by the dwarves. Or at least a lot of the armor of the Elves of Doriath. I'm not so sure about Nargothrond since it was a "hidden" kingdom. However, the dwarves built the place so it would not have been hidden from them.

I think that this is the reason that the Dwarves managed to drive him off, being harder to destroy than the others, but the Dwarves couldn't kill him. They didn't manage to get through his armour, just as the Dwarves of Erebor could'n't pierce the armour of Smaug.

Actually that is not true. The dwarf axes did wound Glaurung, and when he struck down Azaghal and climbed on the body, Azaghal wounded him so badly in the stomach that Glaurung ran off screaming for his mommy.

I think the dwarves just had a built in advantage in that they were harder to set on fire, and fire is the dragon's primary weapon.