Hey Doug, Great to hear from the great cleaning O Guru always informative and interesting. As I'm sure you pointed out many times, a bevy (lots) of in-service failures have been created through the use of no clean/low residue flux with point to point (soldering irons) or localized flow like selective solder, after the initial soldering/cleaning process, since the normally temperature volatized residues don't see required temperatures as they disperse from the heat source toward the cooler periphery. Rework (touchup) or Touchup (rework) is often a traceable source. I suppose that the key is to know what the brew is in the intended flux. As Doug says, "good" flux may be OK, but there are others, and they may require testing as there are a lot of different brews available these days. Mel Parrish STI Electronics Inc. 102 Tribble Drive Madison, AL 35758 256 705 5530 256 461 9566 Fax [log in to unmask] www.stielectronicsinc.com -----Original Message----- From: TechNet [mailto:[log in to unmask]]On Behalf Of Douglas O. Pauls Sent: Monday, October 03, 2005 2:49 PM To: [log in to unmask] Subject: Re: [TN] Mixing Fluxes: Water Sol and Rosin Hoping to hear from Mr Pauls... Well, Kevin, Mr. Pauls is my Dad, but I am willing to take a shot at it. Your basic question of whether you CAN mix flux types on a single assembly can be answered by Yes you can. See, I can answer a question with something besides "It Depends". I shall now pause whilst some individuals pick themselves up off the floor. You have received some good advance so far. I like George Wenger's answer about the order in which you use fluxes. The key to it all, as with most things in electronics manufacturing is knowing what you are doing. If you don't know what you are doing, then mixing flux Bad Idea Kimosabe. Understanding the residues and their effects really dictates what you can and cannot do. Understanding how much flux is needed for any particular task is also important. I have seen companies use "dangerous" fluxes and produce reliable product and I have seen companies use "safe" fluxes and produce garbage. If you have the data that shows you know what you are doing, and your process is robust, then you can use almost anything. Your customer says water solubles, but only rosin fluxes with topical cleaning after that. I am not a big fan of this approach either. Operators have a little flux residue, smear it all over with a topical cleaner and minimal rinsing and "poof" it is magically clean. Anyone who believes this should get their glasses, either prescription or safety, put a drop of oil on one lense, then smear it around over a large area. How clean are the lenses? Partial cleaning leads to more failures than no cleaning. What we do here at Rockwell is to use low solids fluxes and pastes, clean them with an appropriate aqueous cleaner, and in selected programs, use a good low residue flux and leave it in place. Works great for us. So, that is a long winded way of saying "It Depends". Doug Pauls Kevin <[log in to unmask] COM> To Sent by: TechNet [log in to unmask] <[log in to unmask]> cc Subject 10/03/2005 11:34 [TN] Mixing Fluxes: Water Sol and AM Rosin Please respond to TechNet E-Mail Forum <[log in to unmask]> ; Please respond to Kevin <[log in to unmask] COM> Is it acceptable to mix flux types on a single piece of hardware? I have background in MIL/AERO requirements of the "rosin only" creedo. My past experience is with rosin types only, to avoid all the emotional customer issues and testing requirements. However, I am now working for a company and their SOPs dictate use of WS at first solder, followed by water clean. They then dictate rosin for any touchup, with hand clean only. Is there a risk in mixing water sol and rosin on a single piece of hardware? What about resin and rosin? --------------------------------------------------- Technet Mail List provided as a 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/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 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/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 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/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 -----------------------------------------------------