[sdiy] Transition to Lead-Free Hand Soldering

cheater cheater cheater00social at gmail.com
Fri Aug 20 03:49:08 CEST 2021


> if I started doing surface mount then it would probably make more sense to use lead free solder in those projects.

Why? What's the point? smt devices work perfectly well with leaded.

On Fri, Aug 20, 2021 at 3:10 AM Tristan <tu at alphalink.com.au> wrote:
>
> I am still using leaded solder for new projects and maintenance of older gear. Almost all of it is TH but if I
> started doing surface mount then it would probably make more sense to use lead free solder in those
> projects. At present I only use lead free solder for work on RoHS compliant gear or if required for specific
> component compatibility.
>
> Lead free solder joints are known to be more brittle than leaded solder joints as well as being more prone
> to developing tin whiskers. That is probably why you are seeing an increase in broken joints on jacks and
> pots etc. Some lead free solder formulations have been developed in an attempt to get around these
> issues but for me continuing with leaded solder is the simplest solution.
>
> For new designs it would be worth creating them in such a way that components such as connectors,
> jacks, pots and switches are directly secured to the case or panel and do not place mechanical stress on
> their solder connections to the PCB. Creating small I/O boards which connect to the main board via a
> cable could also be used to help isolate the stresses.
>
> /Tristan
>
> On Fri, Aug 20th, 2021 at 10:02 AM, Kenneth Balys <kenny at beatkamp.com> wrote:
>
> > I use lead on that which is leaded. Using fancy new Pb'less solder on a 70's
> > era synth seems wrong.,
> > -------- Original message --------From: cheater cheater via Synth-diy
> > <synth-diy at synth-diy.org> Date: 19/08/2021  19:59  (GMT-05:00) To: Mike
> > Beauchamp <list at mikebeauchamp.com> Cc: synth-diy at synth-diy.org Subject: Re:
> > [sdiy] Transition to Lead-Free Hand Soldering Honestly, go back to leaded.
> > There's no good reason for you to uselead free. You're not saving the
> > environment or anyone's health(including yours) and you're just making work
> > more difficult foryourself.If your flux is sputtering, use (genuine!!!)
> > AmTech 599 tacky flux.This is the best flux I have and it keeps for ages even
> > just left onthe shelf.On Thu, Aug 19, 2021 at 9:50 PM Mike Beauchamp
> > <list at mikebeauchamp.com> wrote:>> I've recently started transitioning into
> > Lead-Free solder for all of my> projects. Now that surface-mount assembly is
> > affordable in small> quantities, it's very easy to get boards made using
> > lead-free finishes> and solders but the hand-soldering is a more difficult
> > transition.>> After a conversation with Kester on the telephone (it's amazing
> > how> helpful companies can be over the phone), they suggested a few products>
> > for me to try and I've now gone through a few rolls to give some opinions.>>
> > For Water-Soluble flux, I am using Kester Part # 24-9574-6403> which is a
> > .031" K100LD solder with the Organic 331 Flux.>> For No-Clean solder, I am
> > using Kester Part # 24-9574-7618> which is a .031" K100LD solder with 3.3%
> > Mildly Activated Rosin 275 Flux.>> K100LD is described as "a eutectic
> > Tin/Copper alloy with controlled> metallic dopants  to control the
> > grainstructure  within  the  solder> joint,  and  to  minimize  the
> > dissolution  of  copper  into  the> solder  pot.    K100LD
> > virtually  eliminates  the  occurrence  of> common  defects  such
> > as  icicling  and  bridging.    The  improved> grainstructure also
> > results in shinier solder joints than traditional> lead-free alloy
> > alternatives".>> I'm not sure what all of that means, but it's a cheaper
> > alternative to> SAC305 at less than half the price for a roll and seems to be
> > designed> with hand-soldering thru-hole components in mind.>>> In use, both
> > solders are "OK". I increased my tip temperature to those> recommended by
> > Kester right away, but was still noticing that the> lead-free solder remains
> > "goopier" and doesn't wet and flow into gaps> nearly as fast, or sometimes at
> > all. As I continued to increase the tip> temperature, this did change and the
> > solder started acting more like the> Lead I've used for 20 years.>> I now
> > have my Hakko 936 set to 800 degrees and things are mostly> working, but not
> > getting great flow on TH components that are being> attached to the ground
> > plane (even with thermal reliefs on the board).> Also at this temperature
> > both solders, especially the 275 Flux is> spattering pretty crazy and eye
> > protection is probably recommended. The> flux residue from this solder has
> > also completely gummed up my fume> extraction tube as well, so that is also
> > something to look out for and> to be changing pre-filters often. I'm also
> > noticing that soldering pins> of cheap plastic IDC headers, it's very easy to
> > melt the plastic with> the 800F heat, so I don't dwell on them for long at
> > all. Maybe better> parts have higher heat tolerance?>> These solders work
> > good enough to get the job done the first time, but> if you try to rework
> > something or correct a mistake, the solders will> suddenly change to sticky
> > goo so I usually just suck the solder off> completely and start with new
> > solder.>>> Kester has a good PDF to troubleshoot lead free hand soldering
> > issues:>
> > https://www.kester.com/Portals/0/Documents/Knowledge%20Base/Lead-free-
> Handsoldering.Final_.4.19.06.pdf>>>
> > So there's definitely a compromise, but those two Kester parts are a> good
> > substitute for the leaded versions I was previously using (as> suggested by
> > Paul S. on here years ago). Next time I redesign my PCBS,> I'm going to use a
> > more aggressive thermal relief on ground plane> thru-holes and I think the
> > tip temperature should be adjusted based on> the physical dimensions of the
> > parts being soldered.>> I'm not sure about the long-term reliability of
> > Lead-Free solder. In my> repair shop, I get a lot of music gear coming in
> > with broken solders on> PCB-mounted jacks, pots, tube sockets, etc and I
> > can't help thinking> that the lead-free solder is more brittle and prone to
> > failure in these> applications.>>> Have you converted to lead-free in your
> > hobby as well? I'm curious to> hear others' suggestions and experiences.>>
> > Mike>>>>>>>>>>>>>>>> _______________________________________________>
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