Re: [Elecraft] Cleaning Solder Flux, Redux
Kester specifically says that rosin residue removal is for cosmetic considerations. Here's the exact quote: "Rosin flux residues are non-conductive and non-corrosive. Under normal circumstances they do not have to be removed from a printed circuit assembly. Rosin residue removal would be for cosmetic considerations. In an environment where the working temperature of the assembly will exceed 200°F the rosin residues will melt and become conductive, in these situations flux removal is required." https://www.kester.com/knowledge-base/faq#46137-rosin-flux-removal-the-question-that-frequently-comes-up-is-do-rosin-flux-residues-need-to-be-removed Again I recommend that you not attempt to remove the flux residue unless you have the technical means to ensure that all traces of it are completely removed. Alan N1AL On 1/1/2022 2:01 PM, Eric Garner wrote: >The only reason for removing flux is purely cosmetic That isn't accurate. Even modern no-clean fluxes can cause corrosion and current leakage if left in place under certain conditions If leakage is a concern, you can specify a surface resistivity level and the boards can be ultrasonic washed or double DI washed to meet that criteria. Eric KI7LTT On Sat, Jan 1, 2022, 11:16 AM Alan Bloom wrote: Another problem with cleaning flux is ionic contamination. The activator in the flux, which is necessary to get the solder to stick, is acidic. As long as the flux is left alone, the ionic contamination is trapped in the rosin where it can do no harm. But when you dissolve it with alcohol or another solvent is is spread over the surface of the board, unless you do a VERY thorough job of cleaning it off. That can cause electrical leakage between circuit nodes and potentially corrosion. The only reason for removing flux is purely cosmetic. When I was at HP/Agilent the rule in production and service was that any flux remaining on the board due to re-work or repair was just left in place. Alan N1AL On 1/1/2022 3:25 AM, CUTTER DAVID via Elecraft wrote: > Ted > If the residue is clear, don't bother, you might create more damage than you realise (ESD). If the residue is brown, you've been using the wrong solder. If you really feel the desire for aesthetics then you can can brush it with IPA, but beware ESD if there are sensitive components on board. Also beware some components can dissolve in some cleaners, eg old style polystyrene capacitors. > > 73 and HNY > David G3UNA > >> On 31 December 2021 at 20:52 eda...@aya.yale.edu wrote: >> >> >> >> >> Is there a consensus among builders of the traditional kits (K1, K2, etc) >> about the best way to remove solder flux from a completed circuit board? >> Some Internet sites recommend acetone, others say isopropyl alcohol. A few >> tout their own product without saying exactly what it is. I remember >> reading someplace that one or the other of those will clean the flux but >> could also cause damage by being absorbed into components. Yes, I know this >> is all purely cosmetic but if it can be done safely I'd like to try it on >> the next kit. Suggestions? >> >> >> >> Thanks, >> >> >> >> Ted, KN1CBR >> >> >> >> __ >> Elecraft mailing list >> Home: http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:Elecraft@mailman.qth.net >> >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html >> Message delivered to d.cut...@ntlworld.com > __ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to a...@elecraft.com __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to garn...@gmail.com __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] Cleaning Solder Flux, Redux
>The only reason for removing flux is purely cosmetic That isn't accurate. Even modern no-clean fluxes can cause corrosion and current leakage if left in place under certain conditions If leakage is a concern, you can specify a surface resistivity level and the boards can be ultrasonic washed or double DI washed to meet that criteria. Eric KI7LTT On Sat, Jan 1, 2022, 11:16 AM Alan Bloom wrote: > Another problem with cleaning flux is ionic contamination. The > activator in the flux, which is necessary to get the solder to stick, is > acidic. As long as the flux is left alone, the ionic contamination is > trapped in the rosin where it can do no harm. But when you dissolve it > with alcohol or another solvent is is spread over the surface of the > board, unless you do a VERY thorough job of cleaning it off. That can > cause electrical leakage between circuit nodes and potentially corrosion. > > The only reason for removing flux is purely cosmetic. When I was at > HP/Agilent the rule in production and service was that any flux > remaining on the board due to re-work or repair was just left in place. > > Alan N1AL > > > On 1/1/2022 3:25 AM, CUTTER DAVID via Elecraft wrote: > > Ted > > If the residue is clear, don't bother, you might create more damage than > you realise (ESD). If the residue is brown, you've been using the wrong > solder. If you really feel the desire for aesthetics then you can can > brush it with IPA, but beware ESD if there are sensitive components on > board. Also beware some components can dissolve in some cleaners, eg old > style polystyrene capacitors. > > > > 73 and HNY > > David G3UNA > > > >> On 31 December 2021 at 20:52 eda...@aya.yale.edu wrote: > >> > >> > >> > >> > >> Is there a consensus among builders of the traditional kits (K1, K2, > etc) > >> about the best way to remove solder flux from a completed circuit board? > >> Some Internet sites recommend acetone, others say isopropyl alcohol. A > few > >> tout their own product without saying exactly what it is. I remember > >> reading someplace that one or the other of those will clean the flux but > >> could also cause damage by being absorbed into components. Yes, I know > this > >> is all purely cosmetic but if it can be done safely I'd like to try it > on > >> the next kit. Suggestions? > >> > >> > >> > >> Thanks, > >> > >> > >> > >> Ted, KN1CBR > >> > >> > >> > >> __ > >> Elecraft mailing list > >> Home: http://mailman.qth.net/mailman/listinfo/elecraft > >> Help: http://mailman.qth.net/mmfaq.htm > >> Post: mailto:Elecraft@mailman.qth.net > >> > >> This list hosted by: http://www.qsl.net > >> Please help support this email list: http://www.qsl.net/donate.html > >> Message delivered to d.cut...@ntlworld.com > > __ > > Elecraft mailing list > > Home: http://mailman.qth.net/mailman/listinfo/elecraft > > Help: http://mailman.qth.net/mmfaq.htm > > Post: mailto:Elecraft@mailman.qth.net > > > > This list hosted by: http://www.qsl.net > > Please help support this email list: http://www.qsl.net/donate.html > > Message delivered to a...@elecraft.com > > __ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to garn...@gmail.com __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Cleaning Solder Flux, Redux
Another problem with cleaning flux is ionic contamination. The activator in the flux, which is necessary to get the solder to stick, is acidic. As long as the flux is left alone, the ionic contamination is trapped in the rosin where it can do no harm. But when you dissolve it with alcohol or another solvent is is spread over the surface of the board, unless you do a VERY thorough job of cleaning it off. That can cause electrical leakage between circuit nodes and potentially corrosion. The only reason for removing flux is purely cosmetic. When I was at HP/Agilent the rule in production and service was that any flux remaining on the board due to re-work or repair was just left in place. Alan N1AL On 1/1/2022 3:25 AM, CUTTER DAVID via Elecraft wrote: Ted If the residue is clear, don't bother, you might create more damage than you realise (ESD). If the residue is brown, you've been using the wrong solder. If you really feel the desire for aesthetics then you can can brush it with IPA, but beware ESD if there are sensitive components on board. Also beware some components can dissolve in some cleaners, eg old style polystyrene capacitors. 73 and HNY David G3UNA On 31 December 2021 at 20:52 eda...@aya.yale.edu wrote: Is there a consensus among builders of the traditional kits (K1, K2, etc) about the best way to remove solder flux from a completed circuit board? Some Internet sites recommend acetone, others say isopropyl alcohol. A few tout their own product without saying exactly what it is. I remember reading someplace that one or the other of those will clean the flux but could also cause damage by being absorbed into components. Yes, I know this is all purely cosmetic but if it can be done safely I'd like to try it on the next kit. Suggestions? Thanks, Ted, KN1CBR __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to d.cut...@ntlworld.com __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to a...@elecraft.com __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Cleaning Solder Flux, Redux
Ted If the residue is clear, don't bother, you might create more damage than you realise (ESD). If the residue is brown, you've been using the wrong solder. If you really feel the desire for aesthetics then you can can brush it with IPA, but beware ESD if there are sensitive components on board. Also beware some components can dissolve in some cleaners, eg old style polystyrene capacitors. 73 and HNY David G3UNA > On 31 December 2021 at 20:52 eda...@aya.yale.edu wrote: > > > > > Is there a consensus among builders of the traditional kits (K1, K2, etc) > about the best way to remove solder flux from a completed circuit board? > Some Internet sites recommend acetone, others say isopropyl alcohol. A few > tout their own product without saying exactly what it is. I remember > reading someplace that one or the other of those will clean the flux but > could also cause damage by being absorbed into components. Yes, I know this > is all purely cosmetic but if it can be done safely I'd like to try it on > the next kit. Suggestions? > > > > Thanks, > > > > Ted, KN1CBR > > > > __ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to d.cut...@ntlworld.com __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
[Elecraft] Cleaning Solder Flux, Redux
Is there a consensus among builders of the traditional kits (K1, K2, etc) about the best way to remove solder flux from a completed circuit board? Some Internet sites recommend acetone, others say isopropyl alcohol. A few tout their own product without saying exactly what it is. I remember reading someplace that one or the other of those will clean the flux but could also cause damage by being absorbed into components. Yes, I know this is all purely cosmetic but if it can be done safely I'd like to try it on the next kit. Suggestions? Thanks, Ted, KN1CBR __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
