Hello Listservers,

there is a long discussion on that very point so for me it looks like alle
people fear to run into problems when rising solder temperature from 220°C
to 260°C but no one knows exactly. I'm only talking of the difference of
temperatures. For me it's no question that moisture is a problem in general.
The mentioned temperature rise is, calculatetd in absolut temperatures,
'only' by 8% which will rise due to basic physics
p * V / T = const.
the vapour pressure as well by 8%. I cannot believe that this rise will be
extreme critical.

For all who are interested: there is literature on water on the web (only in
German) written by Heiner Grimm, University Clausthal-Zellerfeld
(http://www.wissenschaft-technik-ethik.de/wasser.html). With the data given
there I calculated that one drop of water (~ 0.03 ml) completely vapourized
at 250°C will produce a volume of ~ 9 ml at 10 bar pressure. Even if there
is a calculation error this is extreme and it's easy to understand that
moisture is a problem. But what's about the difference of 8% ?

Wolf-Dieter Schmidt
-----------------------------------------------------------
THALES Defence Deutschland GmbH
Industrial Engineering
Land & Joint Systems
Ostendstrasse 3
D-75175 Pforzheim - Germany
-----------------------------------------------------------
Phone: +49 7231 15 3386
Fax: +49 7231 15 3390
mailto: [log in to unmask]

-------------------------------------------------------------------------------Leadfee Mail List provided as a service by IPC using LISTSERV 1.8d
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Leadfree
To temporarily stop/(start) delivery of Leadree for vacation breaks send: SET Leadfree NOMAIL/(MAIL)
Search previous postings at: http://listserv.ipc.org/archives
Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815
-------------------------------------------------------------------------------