What I'm trying to determine is what is myth and what is reality.
Good luck with that one.
On Wikipedia, a lot is written about special materials that are used to build Thinkpad enclosures, but I could never corroborate some of those informations. Then, I was wondering about which Thinkpad models the people who wrote on Wikipedia are speaking.
Wikipedia is full of garbage. I was indifferent to it until I had to go in and correct nonsense written about my ancestors.
It is also curiosity. I like knowing that some material with titanium is like this and some other with carbon fiber is like this, a.s.o.
A degree in chemistry and related sciences might be an idea worth pursuing...you're not going to find much about that type of stuff by playing with ThinkPads...
Concerning titanium, I don't think it is pure titanium (maybe too expensive) but an alloy.
That goes without saying.
When you slightly knock the bottom of a T42, it doesn't sound exactly like common plastic, but like something hybrid between plastic and metal. Hard to know what it is exactly.
The X40 / X41 enclosure looks more common plastic, but the very bottom plate also seems like thus of the T4x series.
Define "common plastic"...
The R series are pure plastic but for some models the enclosure was very well designed (e.g. R31).
I believe that most of us on this board would beg to differ with that...
The T4x have very lightweight metallic profiles inside the enclosure. Some alloy maybe.
's response to your original question....