Mike,
That's a big one.  The answer is that you need to choose the best solder(s) for your application(s).  It is likely your two solders were selected by two different people at two different times.  When choosing materials, talking to the manufacturers about the products, getting samples, and comparing them head-to-head goes a LONG way.  You must also consider reliability.  The best flux formulation is simply not the one that allows you to solder a rusty nail to the hull of a ship.  An important factor is how you plan to clean your parts after soldering is all done, how well you can ensure you get all the residues removed, and the potential impact of any residues remaining on the assemblies.  I suggest you start by reading through some tech articles on cleaning.  This forum, the industry magazines, Foresite, and ACI are some good starting resources.  Bottom line - you don't pick solder materials solely on the basis of supplier or cost.
Good luck.

-----Original Message-----
From: Mike Laroe [mailto:[log in to unmask]] 
Sent: Monday, December 06, 2010 4:06 PM
To: [log in to unmask]
Subject: [TN] HandSoldering Using NC Solders

Currently my company has been using two different Alloys for handsoldering 
both Leaded and RoHs No-Clean Assy's.  For the leaded requirement we are 
using AIM and for Rohs we are using Kester.  We currently stock 4 different 
sizes of each (.015", .020", .025", .031")..  My question and thought is to 
phase out the AIM and strictly only use the Kester for both Leaded and Rohs 
Assy's.  All the Soldering is done with Metcals using the 700 & Pwr Tips.  Are 
there any reasons I shouldn't do this?  

Thanks for your help in advance,

Mike Laroe
Mfg Engineer

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

______________________________________________________________________
This email has been scanned by the MessageLabs Email Security System.
For more information please contact helpdesk at x2960 or [log in to unmask] 
______________________________________________________________________

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