Hy Peter

I agree with you. My comments were only regarding other comments here (no
joke, but physics).
One problem with drying in vacuum is that sometimes some parts of the
plastics evaporate (some have a higher boiling pressure than water, you even
can smell them at room temperature, you can recognize it sometimes if you
come back to your car after a hiking trail of a few days) and this elements
can condense on the contacts causing wetting problems.

Siggi

        ----------
        From:  [log in to unmask] [SMTP:[log in to unmask]]
        Sent:  Donnerstag, 12. Dezember 2002 08:51
        To:  TechNet E-Mail Forum.; Zweigart, Siegmund
        Cc:  [log in to unmask]
        Subject:  Re: [TN] Vacuum


        My understanding of the low temp moisture extraction process is that
it's
        carried out under partial vacuum, not high vacuum, so that the
moisture
        neither boils off rapidly, nor freezes - either of which would cause
        delamination if it were allowed to happen. My initial skepticism
about the
        process was relieved after I spoke to Altos Engineering further
about it,
        although I would want to see the process obtain industry approval or
        conduct my own tests with it before I considered adopting it as a
process
        here.

        Even if it were an approved process, the equipment is too expensive
to
        justify having for my little project.

        Peter



        "Zweigart, Siegmund" <[log in to unmask]>    12/12/2002
03:43 PM
        Sent by: TechNet <[log in to unmask]>

        Please respond to "TechNet E-Mail Forum."; Please respond to
"Zweigart,
        Siegmund"


                      To:  [log in to unmask]

                      cc:  (bcc: DUNCAN Peter/Asst Prin Engr/ST Aero/ST
Group)
                      Subject: Re: [TN] Vacuum












        Just one comment

        If you buy frozen dried food like coffee its is dried under vacuum,
because
        the anomaly of Water.
        So if the Vacuum is high (or low) enough water will freeze because
freezing
        means a volume expansion and this is easier in vacuum.
        If you want the get in trouble with high vacuum specialist put one
drop of
        water in their chambers - have fun.
        One problem with drying under vacuum is also that the transport of
moisture
        away from the component is only possible by diffusion not by
convection.

        Siggi

        ---------------------------------------------------
        Technet Mail List provided as a free service by IPC using LISTSERV
1.8e
        To unsubscribe, send a message to [log in to unmask] with following
text in
        the BODY (NOT the subject field): SIGNOFF Technet
        To temporarily halt or (re-start) delivery of Technet send e-mail to
        [log in to unmask]: SET Technet NOMAIL or (MAIL)
        To receive ONE mailing per day of all the posts: send e-mail to
        [log in to unmask]: SET Technet Digest
        Search the archives of previous posts at:
http://listserv.ipc.org/archives
        Please visit IPC web site http://www.ipc.org/html/forum.htm for
additional
        information, or contact Keach Sasamori at [log in to unmask] or
847-509-9700
        ext.5315
        -----------------------------------------------------






---------------------------------------------------
Technet Mail List provided as a free service by IPC using LISTSERV 1.8e
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Technet
To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL)
To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest
Search the archives of previous posts at: http://listserv.ipc.org/archives
Please visit IPC web site http://www.ipc.org/html/forum.htm for additional
information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315
-----------------------------------------------------