What are the advantages / disadvantages of a rock climbing hat made from hard plastic to one made out of carbon fibre?
I have done a Google search already, but wanted some pointers with people who have experience.
I don't have any specifics on carbon fibre, but from indoorclimbing.com:
Plastic climbing helmets are lighter than the fiberglass or polycarbonate composite helmets, they can also survive more wear and tear.
I use plastic helmets, as I mostly sport climb, and rarely use multiple pitches so I just want a helmet that is light, will take the odd bash from small stones without shattering and will be cheap to replace when I need to.
Since a high quality polycarbonate helmet is now so light, affordable and durable; the added cost and limited weight benefit of carbon fiber seems to be of limited use for all but the most weight conscious or sponsored mountaineers. Plastic fails in a much more human friendly manner without sharp edges of carbon and hard resin that it's generally superior for helmet covering and strong enough for protection from sharp objects.