No chance that these blades have been regularly wiped with WD40 (or similar)?
When this post first came up I think it made mention of the machine being used in coastal Qld for instructing but now I can't find that post. I don't care which school, but it would be interesting to know if they have a policy of getting the students to WD the blades? A light rub on the leading edge is one thing, but a soaking (by an un-supervised/over exhuberant student) would be another.
Cheers FBD