Of the Loctite epoxies, Red Loctite 3621 will provide the best adhesion to tin-plated copper, but it still won't be very good adhesion. It is good initially, but fades after a few thermal cycles due to the delta CTE. The Loctite 3621 adheres better to 99% tin coating, but not so well to Sn63Pb37 (lead is very dense compared with tin). The epoxy that works best from an adhesion standpoint to tinned or soldered copper is Zymet TC201 P, however that is a thermally conductive epoxy, and I don't know if that matters to you. But it adheres well enough to the point that if you attempt to peel off the copper foil after it is cured, some of the FR-4 will come up with it. The key is for both the foil and the FR-4 or other substrate to be very, very clean. By the way, neither of the epoxies I mentioned is a two-part epoxy. If it has to be a two-part, I would go with Armstrong C7 hardener W. Cure schedules are critical to the amount of adhesion you will achieve, at least from a lap shear standpoint. -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of bob wettermann Sent: Thursday, April 09, 2009 12:08 PM To: [log in to unmask] Subject: Re: [TN] Friday Theorizing All: The copper is 1 oz copper used in PCB fab. The tin is plated onto both sides. The adhesive system is a 2part epoxy-resin system (Loctite). I am trying to precict which system will provide better adhesion??? Thanks Bob Wettermann PH 847-767-5745 ________________________________ From: Inge <[log in to unmask]> To: [log in to unmask] Sent: Thursday, April 9, 2009 11:15:28 AM Subject: Re: [TN] Friday Theorizing The correct name of the (vintage) machine is Sebastian stud tester. It's probably followed by a number of more modern ones. From Dage, for instance. Inge ----- Original Message ----- From: "Inge" <[log in to unmask]> To: <[log in to unmask]> Sent: Thursday, April 09, 2009 6:01 PM Subject: Re: [TN] Friday Theorizing > Bob, > > why so thin Tin? And no barrier? What's the purpose? And what do you mean with a 'carrier' ? > When testing conductor adhesion, we simple make a board sample with a number of copper traces, then cut it so we get a large number of square pieces approx. 1x1 inch. Next, we apply a solder paste dot on the center of each square, size about 2 mm. This is followed by soldering kind of needles with a round plate to each square sample. Vapour phase or oven soldered. Finally, the samples are placed in a Sebastian pulling machine's chuck and depress 'pull'. The machine increases the pull force until the plate headed needle separates from the FR4 matrix and the value is presented on the display. Years ago, we did this test frequently on board coupons, but there is little interest in doing it today, because adhesion problems are very rare. > > Inge > > > ----- Original Message ----- From: "bob wettermann" <[log in to unmask]> > To: <[log in to unmask]> > Sent: Thursday, April 09, 2009 5:17 PM > Subject: [TN] Friday Theorizing > > >> Dear Technetters: >> >> Has anyone done any adhesion testing of a 2um tin-electrocoated surface (copper carrier) to FR-4? How about a 0.100um tin electrocoated surface? Can someone theorize on which might give better adhesion using a 2-part epoxy? >> >> Regards >> >> Bob Wettermann >> BEST >> PH 847-767-5745 >> >> --------------------------------------------------- >> Technet Mail List provided as a service by IPC using LISTSERV 15.0 >> 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/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 >> ----------------------------------------------------- > > --------------------------------------------------- > Technet Mail List provided as a service by IPC using LISTSERV 15.0 > 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/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 > ----------------------------------------------------- --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 15.0 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/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 ----------------------------------------------------- --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 15.0 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/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 ----------------------------------------------------- --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 15.0 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/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 -----------------------------------------------------