thanx all for your answers.

really appreciate.
its nice to learn things every day

Out of the Autoclave the vacuum bag will be pushed against your work at a pressure of 15 pounds per square inch. In the Autoclave at a say 4 Bar it will press against the bag at 60 pounds per square inch.

Brian.

(Mental note. I must check for updated answers before I post!    )

rob beat me to it

but the consolidation you get with a clave is superior to everything but high pressure RTM, this is why autoclaves are still predominantly used in Aerospace and F1

Slight variation where you are in the world and at what altitude but if you pull full vac on a part you will have 15PSI of pressure on your part

In a clave you looking at 30-90 psi depending on what your doing

Night and day difference in the finnished parts

Greater consolidation (hence greater interlaminar bond stength) and smaller/less voids. 

in an autoclave you can whack the pressure up to 3/4/5bar (or 3/4/5 atmospheres) therefore providing greater consolidation

i am trying to understand the logic behind autoclave and i end up with stupid question

so how it works. i know it is pressurized chamber.with controlled temperature and vacuum  inlets. thats all clear.

but what that pressure brings if the part is already in vacuum bag?
what is different than just vacuum bagged part in controlled oven?

i know it must bring something, otherwise noone would spend huge amount of money for.

so if someone cold explain me that i would appreciate.

regards
T