wrote:
Can anyone explain to me how an autoclave is used to form hollow (one
piece) frames? I get that there is a bladder inside and that the
autoclave pressurizes pretty high (maybe 50psi) but how do you get the
bladder to inflate? Is there "vacuum" drawn to atmospheric and if so
how do they do this in a two-piece mold?

In other words how does the low pressure get between the composite and
the inner mold line of the female mold?...

You could email Damon Rinard [1] and ask if he knows.

[1] Email link on this page hosted by the nice Mr. Brown:
http://sheldonbrown.com/rinard/carbonqa.htm.
--
Tom Sherman - Fox River Valley