Hi Bob - there are adequate tools within the industry to determine if a flux residue has an unacceptable ionic content - Ion Chromatography, SIR, specific dielectric functionality testing, etc. so determining if your flux and process are compatible is simple -lots of work but simple. Many, many products utilize a "no clean" process using "low residue" flux materials very successfully so it is not hogwash but just good materials & process engineering. Of course, if someone does implement a "no clean" process without doing their due diligence homework and testing, yes, they are not going to be happy with the result. Dave On Mon, Sep 8, 2014 at 10:15 AM, Robert Kondner <[log in to unmask]> wrote: > Dave, > > Maybe it is "Fundamentally" a bit of hog wash. :-) > > The comments that started to thread was your description of why rosin > based flux was good in the use of wire prep. I your description sounds > reasonable to me. > > Richard also seemed to find you information interesting. > > But that thread starting point mentioned the use of RMA but never to use > a "No Clean" flux. That sounds silly to me. If a manufacturer put that > same RMA flux in a bottle and called it "No Clean" I guess it would then > never be used? > > And then I was told to follow the manufacturer's advice! (Maybe that > means as long as the manufacturers advice is not "No Clean".) (Hmmm is Not > "No-Clean" = Clean Always?) > > So I am back to the point of: > > 1. Read the Label > > 2. Follow the recommended processes. (And that included cleaning, if any.) > > 3. If you are not cleaning off flux (or you cannot due to entrapment) > double check everything. Use RMA or No Clean. > > But to have people poo-poo a No Clean as it has not been "Deactivated" > through proper temperature is not verifiable. And until there is competent > advice to be found the idea falls into the hogwash category. > > Just Say No to Hogwash. > > Thanks, > Bob > > -----Original Message----- > From: TechNet [mailto:[log in to unmask]] On Behalf Of David Hillman > Sent: Monday, September 08, 2014 10:43 AM > To: [log in to unmask] > Subject: Re: [TN] tinning wires - flux entrapment and long term reliability > > Hi Bob - as Richard detailed, you need to get down to the flux supplier > application engineers for that detail of information. And nope, I don't > have a clue on why something so fundamental isn't a standard data point on > the tech data sheet. > > Dave > > On Mon, Sep 8, 2014 at 9:28 AM, Robert Kondner <[log in to unmask]> > wrote: > > > Dave, > > > > I did look into this issue, several times. I still sense a bit of > > "Hog Wash" on this subject. I am trying to separate the hogs here. > > > > Go take a look at the Kester 951 data sheet. No "Deactivation > > Temperature" spec there. > > > > Go take a look at Kester 2331-ZX, now this stuff you need to clean. > > Again no "Deactivation Temperature" specified. > > > > So I suggest you get ahold of some flux supplier application folks and > > ask them for "Minimum Processing Temperature for Flux Deactivation". I > > don't think you will find such a specification. > > > > Thanks, > > Bob K. > > > > > > > > -----Original Message----- > > From: TechNet [mailto:[log in to unmask]] On Behalf Of David Hillman > > Sent: Monday, September 08, 2014 10:10 AM > > To: [log in to unmask] > > Subject: Re: [TN] tinning wires - flux entrapment and long term > > reliability > > > > Hi Bob - as Richard detailed, if you get ahold of the flux supplier > > application folks, they have the necessary data for setting up an > > adequate profile and temperature range, application depenedent. The > whole "no clean" > > topic drives me batty - the proper term is "low residue" as I don't > > have my flux suppliers dictating when I should or should not clean. A > > case of marketing edging out engineering on the correct use of technical > terms. > > > > Hey Doug - didn't you and Bill Kenyon have a nice synopsis on the "no > > clean vs low residue" topic? > > > > Dave > > > > On Mon, Sep 8, 2014 at 8:57 AM, Robert Kondner > > <[log in to unmask]> > > wrote: > > > > > Dave, > > > > > > Ok, so if a manufacturer says a flux is categorically "No Clean" we > > > should believe it, right? :-) > > > > > > Offhand I never recall seeing a Minimum Temperature specification > > > for the use of any flux. I recall finding usage temperature ranges, > > > and you find info on how long the flux is active, find statements > > > about must be cleaned or no clean, but have you ever seen a flux > > > with a minimum processing window to be qualified as a "No Clean"? > > > > > > From experience I know that heating profiles of PCB assemblies in > > > reflow ovens are selected such that all the flux does not completely > > "Burn Off". > > > In fact profiles where the flux remains active is what helps make > > > nice shiny solder joints, everyone loves those. > > > > > > I have not seen one shred of evidence in flux usage information > > > that suggest leaving flux residue is safe IF it has been heated to > > > some temperature for some specific length of time. All I see are > > > fluxes listed as "Must Clean" or "No Clean". > > > > > > Do you know of any flux called "You Might Need to Clean"? > > > > > > Bob K. > > > > > > > > > -----Original Message----- > > > From: TechNet [mailto:[log in to unmask]] On Behalf Of David Hillman > > > Sent: Monday, September 08, 2014 9:23 AM > > > To: [log in to unmask] > > > Subject: Re: [TN] tinning wires - flux entrapment and long term > > > reliability > > > > > > Hi Bob - all fluxes have a temperature range, or at least a minimum > > > temperature value, that they should be heated to to accomplish two > tasks: > > > (1) attack/remove the oxides that inhibit the formation of a good > > > solder wetting; (2) decompose the activators such that they are > > > benign in the flux residue. The flux suppliers know their > > > formulations and can provide temperature recommendations to ensure > > > we can create adequate reflow profiles in our processes. > > > > > > Dave > > > > > > On Mon, Sep 8, 2014 at 7:58 AM, Robert Kondner > > > <[log in to unmask]> > > > wrote: > > > > > > > Richard, > > > > > > > > So, I ask: > > > > > > > > Does a rosin based "No Clean" flux need to be completely heated > > > > to high temperature to "De-Activate" the flux? > > > > > > > > If what Dave say is correct the answer is no. I think? > > > > > > > > Bob K > > > > > > > > -----Original Message----- > > > > From: TechNet [mailto:[log in to unmask]] On Behalf Of Stadem, Richard > D. > > > > Sent: Monday, September 08, 2014 8:29 AM > > > > To: [log in to unmask] > > > > Subject: Re: [TN] tinning wires - flux entrapment and long term > > > > reliability > > > > > > > > Dave, I never knew that about RMA fluxes. This is valuable > > > > information, and I thank you for it. > > > > dean > > > > > > > > From: David Hillman [mailto:[log in to unmask]] > > > > Sent: Friday, September 05, 2014 4:03 PM > > > > To: TechNet E-Mail Forum; Stadem, Richard D. > > > > Subject: Re: [TN] tinning wires - flux entrapment and long term > > > > reliability > > > > > > > > Hi Richard - I can provide some additional information. The value > > > > of rosin based fluxes is that when using the proper soldering > > > > temperatures and dwell times, the resulting flux residues are not > > > > mobile, ionic species that can participate in corrosion reactions > > > > (note that there is always an exception to the rule). The rosin > > > > portion of rosin based fluxes can "bind up" any mobile, ionic > > > > species if they are not completely consumed in the soldering > > > > reaction. That is why rosin based fluxes are very robust in > > > > soldering processes. As George and others detailed, "no clean' is > > > > a horrible material descriptor as it is a process categorization > > > > rather than a material categorization. The better term is "low > > > > residue" and as others detailed, not all low residue materials are > > > > created equal. Many low residue fluxes are rosin based materials > > > > so they have applicability for wiring tinning but an engineer has > > > > to do their homework to make sure there is process compatiblilty. > > > > And yes, when folks attempt to use water soluble fluxes in the > > > > same manner as rosin fluxes, bad things happen. The wire tinning > > > > process you learned has its credibility in the rosin chemistry > > > > (the IPA relavence isn't as critical > > > or necessary as Brian can/has detailed) and is supported by the > > > products you detailed. > > > > > > > > I believe Doug and Bill Kenyon put together a "letter" on this > > > > topic and I'll see if Doug can find that for posting thru Steve. > > > > > > > > Dave Hillman > > > > Rockwell Collins > > > > [log in to unmask]<mailto:david.hillman@rockwellcol > > > > li > > > > ns > > > > .com > > > > > > > > > > > > > On Fri, Sep 5, 2014 at 3:00 PM, Stadem, Richard D. < > > > > [log in to unmask]<mailto:[log in to unmask]>> wrote: > > > > I started out in life as a small child with a very large pair of > > > > safety glasses and a leather apron, tinning wires in my father's > > > business. > > > > I later re-learned how to do this from two much older engineers, > > > > who had retired from RCA and Honeywell, and they had been using > > > > this method since they were little boys in their father's shop. > > > > I have also taught this method to my three sons, as there still > > > > seems to be no end of wire tinning requirements even today. > > > > > > > > 1. When stripping the wires, leave the tag end of the insulation > > > > hanging on the end of the wire. This helps prevent the strands > > > > from fraying during handling. > > > > 2. When ready, pull off the tag end of the insulation. Dip the > > > > stripped end of the wire first in IPA up to the end of the > insulation. > > > > 2. Then dip the wire in the RMA flux up to about halfway to the > > > > insulation. Use only RMA flux whenever tinning wires, never OA or > > > > water soluble flux, and never no-clean flux. > > > > 3. Then dip the fluxed end into the solder right up to within .010" > > > > from the insulation and hold for 1 or 2 seconds. This allows the > > > > solder to wick just under the insulation. > > > > 4. Pull the wire out of the solder and "swirl" in clean IPA, and > > > > then lay the wires down flat on a piece of absorbent paper towel. > > > > 5. If an ultrasonic cleaner can be used, ie, the wires are not > > > > soldered to any CCA or any electronic components, then instead of > > > > laying them on the paper towel, drop them into the US cleaner with > > > > a solution of 90% DI water and 10% IPA. Do not exceed the 10% IPA > > > > percentage or you will have a new company swimming pool, but also > > > > you will be minus a few operators and you will gain many new > > > > friends at OSHA and Davidovich, Davidovich, and Rabinovitch, Atty's > at Law. > > > > 6. Once all of the wires have been cleaned for a minimum of 10 > > > > minutes in the US bath, take them out and dry them on a clean > > > > paper > > towel. > > > > > > > > This is a time-tested method, dating back to the late 1950s. > > > > > > > > My understanding (and it may be flawed) is that RMA is used > > > > because even if small amounts are not dissolved in the IPA, > > > > whatever residues that do remain are relatively harmless, because > > > > they are weakened by the IPA already in the wire strands, and > > > > after tinning, most if not all is removed during the "swirling" in > > > > IPA. When the wires are laid down on the paper towel, the IPA and > > > > the flux solids are drawn out, and any remaining residues left > > > > behind are relatively > > harmless. > > > > > > > > I do know that this method of tinning wires was used in the old > > > > Apollo program. > > > > It was also used on the Neartip Mark 5 Torpedo Guidance and > > > > Control systems. > > > > It was also used on the older Mark 2 Torpedoes. > > > > It was also used on the Advanced Lightweight Torpedo. > > > > It was used on the Apache, C5B, Augusta, F-15, F-16, FA-18 > > > > avionics systems, including the flight control computers, the ring > > > > laser gyros, the altimeters, the wind speed indicators, the > > > > flapper controls, the CMRA and HMRA Cruise Missiles, The CH46/CH47 > > > > avionics sets, the Space Shuttle wiring, and about 400-500 > > > > commercial jet plane > > wiring sets. > > > > > > > > I have yet to hear of any wires broken off from corrosion under > > > > the insulation. > > > > > > > > I have heard of many wires corroding away because either water > > > > soluble flux or no-clean fluxes were used. Water soluble fluxes do > > > > not wash out or dilute when dipped in alcohol or water (at least > > > > not very well). Ditto with no-clean fluxes. > > > > > > > > > > > > My only concern is that there are RMA fluxes, and there are RMA > > > > fluxes, and some may be more aggressive than others. > > > > > > > > > > > > > > > > -----Original Message----- > > > > From: TechNet [mailto:[log in to unmask]<mailto:[log in to unmask]>] On > > > > Behalf Of Nutting, Phil > > > > Sent: Friday, September 05, 2014 11:56 AM > > > > To: [log in to unmask]<mailto:[log in to unmask]> > > > > Subject: Re: [TN] tinning wires - flux entrapment and long term > > > > reliability > > > > > > > > Dusting off an old thread here (yes Brian, I listened to your > > > > request for not changing threads). I've been thinking about the > > > > "best" method of wire tinning for some time now and this thread > > > > makes me think the we should dump our no-clean cored wire solder > > > > in favor of something that > > > is more innocuous. > > > > > > > > I have an old roll of Kester 63/37 "44" core saved from years ago > > > > before the switch to lead-free. Is this acceptable for long term > > > > soldered wire reliability. If not, what are the recommendations? > > > > I guess knowing RA or RMA along with manufacturer and "model" > > > > would be useful. Hopefully it is available in 63/37 and lead-free > alloys. > > > > > > > > Thanks in advance for sharing your knowledge and experience, > > > > > > > > Phil Nutting > > > > > > > > -----Original Message----- > > > > From: TechNet [mailto:[log in to unmask]<mailto:[log in to unmask]>] On > > > > Behalf Of Carl VanWormer > > > > Sent: Tuesday, June 10, 2014 11:55 AM > > > > To: [log in to unmask]<mailto:[log in to unmask]> > > > > Subject: Re: [TN] tinning wires - flux entrapment and long term > > > > reliability > > > > > > > > There sure are a lot of scare stories about flux and reliability. > > > > I'm now wondering if a solution based on crimping some sort of > > > > ferrule or machined pin onto the ends of the wires and then > > > > soldering those metal parts into the PCB holes might be a more > > > > reliable approach. Have any of > > > "you guys" > > > > seen that type of solution to this problem? > > > > > > > > Thanks, > > > > Carl > > > > > > > > > > > > Carl B. Van Wormer, P.E., AE7GD > > > > Senior Hardware Engineer > > > > Cipher Engineering LLC > > > > 21195 NW Evergreen Pkwy Ste 209 > > > > Hillsboro, OR 97124-7167 > > > > 503-617-7447x303<tel:503-617-7447x303> > > > > [log in to unmask]<mailto:[log in to unmask]> > > > > http://cipherengineering.com > > > > > > > > > > > > > > > > -----Original Message----- > > > > From: TechNet [mailto:[log in to unmask]<mailto:[log in to unmask]>] On > > > > Behalf Of Karen Tellefsen > > > > Sent: Tuesday, June 10, 2014 6:00 AM > > > > To: [log in to unmask]<mailto:[log in to unmask]> > > > > Subject: Re: [TN] tinning wires - flux entrapment and long term > > > > reliability > > > > > > > > I would use Kester 186-18 instead for tinning. Alpha 615-15 is > > > > another good choice. > > > > > > > > Karen Tellefsen - Electrical Testing Alpha / 109 Corporate Blvd./ S. > > > > Plainfield, NJ 07080 [log in to unmask] > > > > <mailto:[log in to unmask]> 908-791-3069<tel:908-791-3069> > > > > > > > > > > > > > > > > > > > > From: Steve Gregory <[log in to unmask]<mailto:[log in to unmask] > >> > > > > To: <[log in to unmask]<mailto:[log in to unmask]>>, > > > > Date: 06/09/2014 05:43 PM > > > > Subject: Re: [TN] tinning wires - flux entrapment and long > term > > > > reliability > > > > Sent by: TechNet <[log in to unmask]<mailto:[log in to unmask]>> > > > > > > > > > > > > > > > > Hi Richard, > > > > > > > > Good information! But can I ask a question about a particular > > > > no-clean flux? It's about Kester 951. In their datasheet they say > > > > that it contains a "corrosion inhibitor" such that no corrosion > > > > products are formed when bare copper surfaces are exposed to humid > > > > environments. Do you have any idea what that might be? > > > > > > > > We use it as a touch-up flux for our no-clean soldering and do use > > > > it to tin wires. I know that some of that flux gets somewhere > > > > where it doesn't get cleaned, and probably didn't get exposed to a > > > > lot of heat when you're doing point-to-point touch-up and > > > > soldering with a single > > > iron. > > > > > > > > We haven't had an issue with this flux, at least any that I know of. > > > > But it doesn't mean that there isn't one. The operators sometimes > > > > complain when they use it because it evaporates so fast though. > > > > > > > > Just curious what the "corrosion inhibiter" might be. The SDS says > > > > the flux contains ethanol (50-65%), isopropanol (20-25%), n-butyl > > > > acetate (5-10%), methanol (2.5-5%), and adipic acid (1-2.5%). > > > > Everything listed is pretty much a solvent except for the adipic > acid. > > > > > > > > Steve > > > > > > > > > > > > -----Original Message----- > > > > From: TechNet [mailto:[log in to unmask]<mailto:[log in to unmask]>] On > > > > Behalf Of Stadem, Richard D. > > > > Sent: Monday, June 9, 2014 2:23 PM > > > > To: [log in to unmask]<mailto:[log in to unmask]> > > > > Subject: Re: [TN] tinning wires - flux entrapment and long term > > > > reliability > > > > > > > > I agree with George, and also with many others who feel that > > > > cleaning with IPA is not a very good approach. > > > > I should have mentioned also that through the years that I have > > > > seen wires tinned with RMA flux, then soaked in IPA, then that was > > > > followed by a DI wash. > > > > > > > > The old-time engineers back in the 60s and 70s showed me by using > > > > 3 stages of wires cut open to show what the strands looked like > > > > under the insulation. Different oldtimers showed me this trick > > > > more than once, and I have never forgotten it. > > > > > > > > First, the operators were trained to insert the wires into the RMA > > > > flux only halfway up the stripped portion (generally 1/8th inch to > 1/4" > > > > striplength). > > > > Next, the operator was trained to insert the wire only up to just > > > > below the end of the insulation. Some of the RMA flux would always > > > > ride up to the insulation, and the solder would actually flow just > > > > under the insulation, seldom more than .050" past the end of the > > > > insulation. In other words, if you stop the stranded wire just > > > > short of the insulation, the solder continues to wick up to a > > > > point just under > > > the end of the insulation. > > > > Then, when the wires were not cleaned with IPA at all, the cutaway > > > > view would always show a small amount of flux just under the end > > > > of the insulation. > > > > When cleaned in the IPA only, but not followed with a water wash, > > > > when you cut the insulation away you "sometimes" saw a very small > > > > amount of > > > flux. > > > > But when you did all three, any flux residue under the insulation > > > > (if > > > > present) could not be seen. It does not mean it wasn't there; it > > > > just was not visible even at 20X. > > > > > > > > And in all cases, the oldtimers were never concerned with RMA flux > > > > residues being left behind under the insulation; they felt it was > > > > not a concern even to leave the RMA flux behind, with no cleaning. > > > > > > > > But NOT water soluble (OA) and NOT no-clean fluxes. The no-clean > > > > activators are sometimes even more aggressive than RMA. That is > > > > still > > > true. > > > > So I stand by the statement that when tinning wires, only RMA flux > > > > should be used, some type of solvent should be used to at least > > > > suspend the RMA solids, and some type of final rinse or wash > > > > process should be used. If all of those are done, I do not think > > > > there is ever a concern for the wires rotting away under the > insulation. > > > > > > > > And one more item: If you are just cleaning tinned wires (no > > > > connector bodies, sleeving, circuit boards or components,etc.) I > > > > have found that following the solvent clean with an ultrasonic > > > > cleaning process where the entire wire or wire assembly is > > > > immersed in hot DI water with a 6% saponifier will get all of the > > > > flux out from under the end of the insulation. > > > > > > > > I am talking about the end of the insulation, not 1/2" up the > > > > insulation or anything like that. > > > > > > > > > > > > > > > > -----Original Message----- > > > > From: TechNet [mailto:[log in to unmask]<mailto:[log in to unmask]>] On > > > > Behalf Of Wenger, George M. > > > > [Contractor] > > > > Sent: Monday, June 09, 2014 1:21 PM > > > > To: [log in to unmask]<mailto:[log in to unmask]> > > > > Subject: Re: [TN] tinning wires - flux entrapment and long term > > > > reliability > > > > > > > > As someone who sent 33 years working in the "Bell System" were > > > > solder assembly quality/reliability was the primary concern, I'll > > > > throw my two cents into this discussion. I've never like the name > > "No-Clean". > > > > Any flux used for soldering that doesn't go through a cleaning > > > > process would be a "No-Clean" if the meaning is it wasn't cleaned > > > > off. The old BellCore (now > > > > Telcordia) GR-78 gives criteria for determining if a soldering > > > > flux residue needs to be cleaned off for reliability reasons. > > > > If you make a solder joint with a flux and don't clean it off and > > > > it passes the BellCore reliability testing then we would consider > > > > that flux a reliable "Leave-Behind" flux meaning if the flux > > > > residue wasn't cleaned off there were no reliability risks. In > > > > general most of the old fluxes classified as R & RMA passed the > "leave-Behind" > > > > requirement. In fact, our experience was that especially for RMA > > > > fluxes the reliability was much better if you did leave them > > > > behind rather than tried to clean them. If you take an RMA flux > > > > and try cleaning it with alcohol (which isn't a very good solvent) > > > > what you wind up doing is dissolving and removing most of the > > > > rosin in the flux residue, which is what was encapsulating the > > > > ionic activators, which in turn allowed any ionic activators to be > > > > mobile and the first time the humidity increased you had the worse > > > > case for corrosion (moisture, > > > activators, and electrical potential). > > > > > > > > I can see that with a low-solids type "No-Clean" flux that the > > > > flux would wick up the braided wires and yes when a soldering iron > > > > was placed on where you wanted to make the solder joint the flux > > > > activators would be heated and reduce oxides and allow a good > > > > solder joint to form but the flux that wicked up the wires may not > > > > have gotten to a high enough temperature to de-activate the > > > > activators and then the humidity goes up in use you could have a > > > > problem. If I were pre-tinning braided wires I would only us an > > > > RMA flux qualified > > > according to BellCore GR-78 to be a "Leave-Behind". > > > > > > > > Regards, > > > > George > > > > George M. Wenger > > > > Failure Signature & Characterization Lab LLC > > > > 609 Cokesbury Road, High Bridge, NJ 08829 > > > > (908) 638-8771<tel:%28908%29%20638-8771> Home (732) > > > > 309-8964<tel:%28732%29%20309-8964> > > > > Mobile E-mail > > > > [log in to unmask]<mailto:[log in to unmask]> > > > > [log in to unmask]<mailto:[log in to unmask]> > > > > > > > > > > > > -----Original Message----- > > > > From: TechNet [mailto:[log in to unmask]<mailto:[log in to unmask]>] On > > > > Behalf Of Carl VanWormer > > > > Sent: Monday, June 09, 2014 12:59 PM > > > > To: [log in to unmask]<mailto:[log in to unmask]> > > > > Subject: Re: [TN] tinning wires - flux entrapment and long term > > > > reliability > > > > > > > > I've heard stories of no-clean and hand soldering causing problems. > > > > In an IR-reflow oven, all of the no-clean flux achieves the > > > > passivation temperature, becoming inert. With hand soldering, the > > > > flux melts, runs away from the heat source, and penetrates any > > > > tiny > > > crevice it can find. > > > > There is an area at the perimeter of the heated area that is hot > > > > enough to cause the flux to flow, but not hot enough to cause it > > > > to > > > become active. > > > > If this is true, than this is the problem I'm worried about. > > > > Comments, please? > > > > > > > > Thanks, > > > > Carl > > > > > > > > > > > > > > > > Carl B. Van Wormer, P.E., AE7GD > > > > Senior Hardware Engineer > > > > Cipher Engineering LLC > > > > 21195 NW Evergreen Pkwy Ste 209 > > > > Hillsboro, OR 97124-7167 > > > > 503-617-7447x303<tel:503-617-7447x303> > > > > [log in to unmask]<mailto:[log in to unmask]> > > > > http://cipherengineering.com > > > > > > > > > > > > -----Original Message----- > > > > From: TechNet [mailto:[log in to unmask]<mailto:[log in to unmask]>] On > > > > Behalf Of Steve Gregory > > > > Sent: Monday, June 09, 2014 9:49 AM > > > > To: [log in to unmask]<mailto:[log in to unmask]> > > > > Subject: Re: [TN] tinning wires - flux entrapment and long term > > > > reliability > > > > > > > > It's been some years back, but we were building a cabinet along > > > > with all the boards and cables. The cables had silver plated > > > > braided shielding over them and we would have to solder the shield > > > > wires to either a lug or contact. We were using manufacture XXX > no-clean flux. > > > > It had been a rainy spring that year, and rained about every other > > > > day for at least a month, so you know the humidity was high. > > > > > > > > One of the supervisors came to me after that month and said; > > > > "Steve, we got a problem, all the cables in the cabinets are turning > green..." > > > > so I went and looked at them. Sure enough the shield wires were > > > > turning green, and it was down close to the end sections of the > > > > cables where they had been > > > > soldered: > > > > > > > > http://stevezeva.homestead.com/files/Green_Junk_1.jpg > > > > > > > > http://stevezeva.homestead.com/files/Green_Junk_2.jpg > > > > > > > > http://stevezeva.homestead.com/files/Green_Junk_3.jpg > > > > > > > > http://stevezeva.homestead.com/files/Green_Junk_Close.jpg > > > > > > > > I had a hard time figuring out how this was happening, because > > > > right at the ends where the soldered connection it was fine. The > > > > connections were soldered and cleaned with alcohol. Best I could > > > > figure was that the operators had flux on their fingers when they > > > > handled the cables and got the flux up on the cable where it > > > > wasn't reacted with heat, and wasn't cleaned, and with the high > > > > humidity that we had that month turned the shield wire green. > > > > > > > > We switched the no-clean flux to manufacture XXX and the problem > > > > went > > > away. > > > > > > > > Steve > > > > > > > > > > > > -----Original Message----- > > > > From: TechNet [mailto:[log in to unmask]<mailto:[log in to unmask]>] On > > > > Behalf Of Nutting, Phil > > > > Sent: Monday, June 9, 2014 8:25 AM > > > > To: [log in to unmask]<mailto:[log in to unmask]> > > > > Subject: Re: [TN] tinning wires - flux entrapment and long term > > > > reliability > > > > > > > > So for many years I have followed the discussion about flux > > > > cleaning and alcohol always get mentioned as a great way of > > > > dissolving the flux and depositing it on a much wider area. There > > > > has to be a better way to "clean" the wire entrapped flux if it > > > > really must be cleaned. I agree that OA flux is not a good > > > > solution. My current choice is to use > > > "no-clean" > > > > flux cored solder when tinning wires and then leave it alone. > > > > Soldering the wire into the board can then be done with "no-clean" > > > > or other flux cored solder. Where we do not make anything that is > > > > designed as mission critical this process seems to work for us. > > > > > > > > Phil Nutting > > > > > > > > -----Original Message----- > > > > From: TechNet [mailto:[log in to unmask]<mailto:[log in to unmask]>] On > > > > Behalf Of Stadem, Richard D. > > > > Sent: Monday, June 09, 2014 9:30 AM > > > > To: [log in to unmask]<mailto:[log in to unmask]> > > > > Subject: Re: [TN] tinning wires - flux entrapment and long term > > > > reliability > > > > > > > > You do not tell us what flux you are using. > > > > But as a general rule, one must never tin insulated wires using OA > > flux. > > > > Only RMA or no-clean should be used, and that followed by dipping > > > > the tinned ends in alcohol. > > > > > > > > > > > > -----Original Message----- > > > > From: TechNet [mailto:[log in to unmask]<mailto:[log in to unmask]>] On > > > > Behalf Of Carl VanWormer > > > > Sent: Friday, June 06, 2014 8:20 AM > > > > To: [log in to unmask]<mailto:[log in to unmask]> > > > > Subject: [TN] tinning wires - flux entrapment and long term > > > > reliability > > > > > > > > My understanding: > > > > While tinning wires with conventional soldering methods, the wire > > > > is heated and the flux-cored solder is applied to the wire. As > > > > the flux is melted, it wicks up between the wires and the solder > > > > flows in, wetting the wires. The liquefied flux flows up the > > > > wires farther than the solder, and some of the un-passivated flux > > > > is trapped inside the insulation, around the Copper strands where > > > > the > > solder stopped flowing. > > > > > > > > My experience: > > > > One of our control modules had failed in an automotive "road splash" > > > > environment. Our connector terminals had been soldered to the > > > > wires that came out of the "waterproof" strain-relief assembly. > > > > Troubleshooting let me to cable harness with an open circuit > > > > between a wired connector pin and the other end of the wire. The > > > > wire and pin looked good, but a gentle tug on the pin popped the > > > > 5mm length of soldered wire out of the wire's insulation, > > > > revealing a discoloration at the end of the solder-flow where the > > > > Copper wire had been > > > "disappeared". > > > > A few mm inside the wire insulation, there was another discolored > > > > blob at the end of the wire's total length of good Copper wire. > > > > Our conclusions of "not quite waterproof" and "chemistry > > > > experiment" led me to be concerned about the problem. > > > > > > > > Current worry: > > > > We have a product with a "requirement" that some 16-gauge stranded > > > > Copper wires be soldered to our PC board. The plan is to have the > > > > cable assembly arrive with pre-tinned wires, and then the wires > > > > will be soldered to the board with "no-clean" flux. The product > > > > is not expected to be in the water, but may be "near" a wet > > > > environment, maybe mounted in a pouch on some motorcycle gear. > > > > I'm worried about the tinning process forcing un-passivated flux > > > > up, inside the > > > insulation, to wait for a "humid" > > > > condition to start another "chemistry experiment." > > > > > > > > Questions: > > > > > > > > 1. Assuming we must solder wires to my PC board, is there any > > > > guidance on how to keep "chemistry experiments" from happening on > > > > my product? > > > > > > > > 2. Are there any other "very small" connection methods for 15 > Amp > > > > wires that I should consider that I might be able to fit on my > > > > tiny PC board that would eliminate my worry? > > > > > > > > 3. Am I just being overly paranoid? > > > > > > > > Thanks, > > > > Carl > > > > > > > > > > > > > > > > > > > > > > > > Carl B. Van Wormer, P.E., AE7GD > > > > Senior Hardware Engineer > > > > Cipher Engineering LLC > > > > 21195 NW Evergreen Pkwy Ste 209 > > > > Hillsboro, OR 97124-7167 > > > > 503-617-7447x303 > > > > [log in to unmask]<mailto:[log in to unmask] > > > ><mailto: > > > > [log in to unmask]<mailto:[log in to unmask]>> > > > > http://cipherengineering.com<http://cipherengineering.com/> > > > > > > > > This message may contain confidential and/or proprietary > > > > information, and is intended for the person/entity to whom it was > > > > originally addressed. 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