Carl, the tan material you see is probably CEM-1 or CEM-3.  CEM stands for
Cyanate Ester - Modified.  It is a low cost laminate that is more often
punched than routed, and usually single sided.  Never used in Class 3
electronics (at least by smart people).  Usually only class 1 stuff.

As far as a single free omnibus reference that gives you all the materials
properties, I doubt that you would find one.  Propeties depend on the
amount of blended additives each formulator uses, so will vary from
laminate to laminate.  Two references I recommend are:

Electronic Materials and Processes - 2dn Edition: Charles Harper and Ronald
Sampson.
Printed Circuits Handbook, 4th Edition. Clyde Coombs.

To give you a general flavor for CEM, here are some general properties:
dielectric constant @ 1MHz, 3.5-3.7 for a 70% resin content, 3.9-4.1 for a
55% resin content
Dissipation factor, .002 - .003
TG - 290C
Peel strength - 8-12 lb/in at 25C.

Is the above what you were looking for?  Is it dry enough for the forum?
As a perpetual joker, I now live in fear of exile from the forum.....

Doug Pauls




                      Carl VanWormer
                      <[log in to unmask]>        To:       [log in to unmask]
                      Sent by: TechNet         cc:
                      <[log in to unmask]>        Subject:  Re: [TN] PCB Material Question


                      04/25/2003 10:04
                      AM
                      Please respond to
                      "TechNet E-Mail
                      Forum."; Please
                      respond to Carl
                      VanWormer






I can contact the FR-4 laminate manufacturers, but I don't know what the
tan material is that is used in PC power supplies, so I don't know who to
contact . . .Any clues on what that stuff is?

---------------------------------------------------
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
-----------------------------------------------------