Lead Solder Wire with Ag Vs Cu

[2X]

Hello,
I am using the STANNOL (Type: HS10) solder with Sn62Pb36Ag2 and I am very pleased, but do you know what is the pros and cons with a lead solder that contains Ag(Silver) or Cu(Copper). I read that the adition of Cu or Ag makes the solder more hard but I am not sure if practical makes any noticable difference. I found these two "S-Sn60Pb39Cu1" "S-Sn62Pb36Ag2" of STANNOL brand. Also, I have used CYNER solder Sn60Pb40 and Alpha Sn63Pb47 but my favorite is STANNOL Sn62Pb36Ag2.


https://www.elmisrl.it/wp-content/uploads/2024/03/Stannol-soldering-materials-EN-2024-1-web.pdf

[tooki]

The silver lowers the melting point by a tiny amount. Beyond that, the reason for silver or copper is to prevent the solder from leaching silver or copper from the joint. This matters when soldering to something that has only a thin plating of silver (like on ceramic hybrid circuits, early SMD resistors, and famously the ceramic terminal strips in old Tektronix oscilloscopes) or copper (like on the horrid copper-clad aluminum wire on some cheap Chinese junk). Copper-bearing solder also caused less soldering tip erosion back in the days when we used unplated, bare copper soldering iron tips. But that doesn’t apply to the plated tips that have been standard for years.

But 63/37 eutectic flows a tiny bit better than silver- or copper-bearing solder. And if you think Stannol is good, then you should try Kester 44, which is nicer still.

[jpanhalt]

Isn't Kester 44 descriptive of the flux, not the solder?  I use it too, and that solder flux is available in solder with or without silver.

[2X]

I have use CYNEL solder Sn60Pb40 and Alpha Sn63Pb47, Felder Sn60Pb40 and STANNOL Sn62Pb36Ag2 (from my experience flows better from the others). I have never use Kester. Do you beleive is above all the brands that I 've mentioned?
Also I remember that I 've read here on the forum in another old thread that the Felder is the best lead free solder and I would like to try it but for some reason always I leave for a future.
Any recommendations are welcomed.


https://www.conrad.com/en/p/felder-lottechnik-iso-core-clear-sac305-solder-reel-sn96-5ag3cu0-5-0-250-kg-0-5-mm-2226454.html

[jpanhalt]

I have read that the magic of Kester 44 flux is the 0.44% of bromides and chlorides it has (https://www.kester.com/downloads/data-sheets).  That may not be suitable for all applications.

[tooki]

Isn't Kester 44 descriptive of the flux, not the solder?  I use it too, and that solder flux is available in solder with or without silver.

It is.

My point in that sentence was that if OP thinks that Stannol is good, then they will likely find Kester 44 to be better, because IMHO none of Stannol’s fluxes are as good, independent of alloy. Conversely, my mention of 63/37’s flow characteristics over Ag-or Cu-bearing alloys is independent of brand and flux.

[tooki]

I have read that the magic of Kester 44 flux is the 0.44% of bromides and chlorides it has (https://www.kester.com/downloads/data-sheets).  That may not be suitable for all applications.

Technically true, but irrelevant for the overwhelming majority of situations. Remember, the 44 data sheet explicitly says:

44 possesses excellent fluxing ability; the flux residues are non-corrosive, non-conductive and do not require removal for most applications under normal conditions of use.

[tooki]

I have use CYNEL solder Sn60Pb40 and Alpha Sn63Pb47, Felder Sn60Pb40 and STANNOL Sn62Pb36Ag2 (from my experience flows better from the others). I have never use Kester. Do you beleive is above all the brands that I 've mentioned?
Also I remember that I 've read here on the forum in another old thread that the Felder is the best lead free solder and I would like to try it but for some reason always I leave for a future.
Any recommendations are welcomed.


https://www.conrad.com/en/p/felder-lottechnik-iso-core-clear-sac305-solder-reel-sn96-5ag3cu0-5-0-250-kg-0-5-mm-2226454.html

I haven’t used Cynel or Alpha before, and I never got the chance to try Felder SnPb before REACH took it off store shelves. But my experience with Felder’s lead-free is that it’s decidedly better than Stannol lead-free. I definitely prefer Kester leaded to Stannol leaded (and yes, I’ve compared them side by side).


You probably are referring to my recommendation of Felder lead-free. But to be absolutely clear, I recommended the Sn100Ni+ alloy specifically (with the “Ultra-Clear” flux), not the SAC305 you linked.

This is the one I recommend: https://www.conrad.com/en/p/felder-lottechnik-iso-core-ultra-clear-sn100ni-solder-lead-free-reel-sn99-25cu0-7ni0-05-0-250-kg-0-5-mm-2226459.html
You can get it for nearly half the price from Reichelt: https://secure.reichelt.com/ch/de/loetzinn-bleifrei-mit-kupferanteil-0-5-mm-250-g-lz-f4-bf-0-5-250-p258990.html?&nbc=1

Good leaded solder is still better, but I’d take Felder SnNi100+ over any Stannol lead-free any day.

[2X]

Many thanks to all for your replies. At the Felder lead free solder that you recommend me is the Ni (Nickel) addition to the composition of the solder which make it better or the type of flux (as I understand from the datasheets must be the same type and the SAC305 has 3.5% instead of the Sn100Ni+ where has 2.2%) that has in his core? The only informations that I found about the Sn100Ni is the below.

https://www.felder.de/products/electronic-applications/wave-soldering-selective-soldering/sc-electronic-solders-tin-copper/loetdraht-iso-core-ultra-clear-51941040.html

https://www.felder.de/files/felder/pdf/EN_51-ISO-Core_UltraClear_lead_free.pdf

https://www.felder.de/downloads-37790/catalogue.html

file:///C:/Users/Christos/Downloads/Gesamtlieferprogramm_2012_EN-kl.pdf


Do you know any European site/s (or something like Mouser Electronics) so to buy and try Kester 44?

[tooki]

It’s the combination of good flux and the alloy (mostly tin, a bit of copper, and trace amounts of nickel and germanium; the last two improve flow quite a bit).

Mouser and Digi-Key both carry Kester 44. Unusually, in this case Mouser has the better parametric search, because they have a field for the flux amount. For Kester, size 66 is the 3.something-percent.

[2X]

It’s the combination of good flux and the alloy (mostly tin, a bit of copper, and trace amounts of nickel and germanium; the last two improve flow quite a bit).

Mouser and Digi-Key both carry Kester 44. Unusually, in this case Mouser has the better parametric search, because they have a field for the flux amount. For Kester, size 66 is the 3.something-percent.

I found the below. I beleive these are ok.? I chosed the Sn63Pb37 analogy because also I beleive that have better flow.

44 Flux-Cored Wire
https://www.kester.com/products/product/44-flux-cored-wire


0.5mm wire
2463370010
https://www.digikey.gr/en/products/detail/kester-solder/24-6337-0010/91415
https://gr.mouser.com/ProductDetail/Kester/24-6337-0010-1-LB?qs=m5JL4TdtMhwlpodi71ffBw%3D%3D


1mm wire
2463370039
https://www.digikey.gr/en/products/detail/kester-solder/24-6337-0039/31099
https://gr.mouser.com/ProductDetail/Kester/24-6337-0039?qs=m5JL4TdtMhzLpdVxZ4GTGw%3D%3D
sometimes I can't understand the mouser about the availability-prices

[2X]

It’s the combination of good flux and the alloy (mostly tin, a bit of copper, and trace amounts of nickel and germanium; the last two improve flow quite a bit).

Mouser and Digi-Key both carry Kester 44. Unusually, in this case Mouser has the better parametric search, because they have a field for the flux amount. For Kester, size 66 is the 3.something-percent.

Because I found many part numbers of Kester could you tell me if the below are these that you told me to try?


0.5mm wire
2463370010
https://www.digikey.gr/en/products/detail/kester-solder/24-6337-0010/91415
https://gr.mouser.com/ProductDetail/Kester/24-6337-0010-1-LB?qs=m5JL4TdtMhwlpodi71ffBw%3D%3D

1mm wire
2463370039
https://www.digikey.gr/en/products/detail/kester-solder/24-6337-0039/31099
https://gr.mouser.com/ProductDetail/Kester/24-6337-0039?qs=m5JL4TdtMhzLpdVxZ4GTGw%3D%3D

[jpanhalt]

As mentioned earlier and confirmed by you, Kester 44 refers to the flux.  Kester makes many different solders with that flux.

As for what to use, can you use leaded or must you use lead free?  If leaded, 63/37 is by far my favorite for electronics.  I also have the equivalent eutectic with 2% silver that's been used occasionally for no particular reason.

As for diameter, that depends on what you are soldering.  I use both sizes.  The smaller (nominally 0.015") is used for SMD's; the larger (nominally 0.031") for through-hole.  I have some that's even larger that gets used with a larger iron for even bigger stuff. Doing that is pretty infrequent today.

[2X]

Below are some of the solder wires that I have used.

[mariush]

Wikipedia has a long list of solder alloys : https://en.wikipedia.org/wiki/Solder_alloys

You can see in the description what addition of various percentages of Silver or Copper do to the solder.

Euctetic formulations should be better most of the time ... for example 63/37 is better than 60/40, but 60/40 is more user friendly, more bad soldering iron friendly (stays liquid / soft for longer time, stays liquid within a wider range)


ex

Sn63Pb37    183[19]    Pb    Yes    Sn63, ASTM63A, ASTM63B. Common in electronics; exceptional tinning and wetting properties, also good for stainless steel. One of the most common solders. Low cost and good bonding properties. Used in both SMT and through-hole electronics. Rapidly dissolves gold and silver, not recommended for those.[8] Sn60Pb40 is slightly cheaper and is often used instead for cost reasons, as the melting point difference is insignificant in practice. On slow cooling gives slightly brighter joints than Sn60Pb40.[17]

Sn62Pb37Cu1    183[18]    Pb    Yes    Similar to Sn63Pb37. Copper content increases hardness of the alloy and inhibits dissolution of soldering iron tips and part leads in molten solder.

Sn62Pb36Ag2    179[5]    Pb    Yes    Sn62. Common in electronics. The strongest tin-lead solder. Appearance identical to Sn60Pb40 or Sn63Pb37. Crystals of Ag3Sn may be seen growing from the solder. Extended heat treatment leads to formation of crystals of binary alloys. Silver content decreases solubility of silver, making the alloy suitable for soldering silver-metallized surfaces, e.g. SMD capacitors and other silver-metallized ceramics.[15][17][22] Not recommended for gold.[8] General-purpose.

Sn60Pb40    183    190[5]   188[6]    Pb    Near    Sn60, ASTM60A, ASTM60B. Common in electronics, most popular leaded alloy for dipping. Low cost and good bonding properties. Used in both SMT and through-hole electronics. Rapidly dissolves gold and silver, not recommended for those.[8] Slightly cheaper than Sn63Pb37, often used instead for cost reasons as the melting point difference is insignificant in practice. On slow cooling gives slightly duller joints than Sn63Pb37.

[2X]

Wikipedia has a long list of solder alloys : https://en.wikipedia.org/wiki/Solder_alloys

You can see in the description what addition of various percentages of Silver or Copper do to the solder.

Euctetic formulations should be better most of the time ... for example 63/37 is better than 60/40, but 60/40 is more user friendly, more bad soldering iron friendly (stays liquid / soft for longer time, stays liquid within a wider range)


ex

Sn63Pb37    183[19]    Pb    Yes    Sn63, ASTM63A, ASTM63B. Common in electronics; exceptional tinning and wetting properties, also good for stainless steel. One of the most common solders. Low cost and good bonding properties. Used in both SMT and through-hole electronics. Rapidly dissolves gold and silver, not recommended for those.[8] Sn60Pb40 is slightly cheaper and is often used instead for cost reasons, as the melting point difference is insignificant in practice. On slow cooling gives slightly brighter joints than Sn60Pb40.[17]

Sn62Pb37Cu1    183[18]    Pb    Yes    Similar to Sn63Pb37. Copper content increases hardness of the alloy and inhibits dissolution of soldering iron tips and part leads in molten solder.

Sn62Pb36Ag2    179[5]    Pb    Yes    Sn62. Common in electronics. The strongest tin-lead solder. Appearance identical to Sn60Pb40 or Sn63Pb37. Crystals of Ag3Sn may be seen growing from the solder. Extended heat treatment leads to formation of crystals of binary alloys. Silver content decreases solubility of silver, making the alloy suitable for soldering silver-metallized surfaces, e.g. SMD capacitors and other silver-metallized ceramics.[15][17][22] Not recommended for gold.[8] General-purpose.

Sn60Pb40    183    190[5]   188[6]    Pb    Near    Sn60, ASTM60A, ASTM60B. Common in electronics, most popular leaded alloy for dipping. Low cost and good bonding properties. Used in both SMT and through-hole electronics. Rapidly dissolves gold and silver, not recommended for those.[8] Slightly cheaper than Sn63Pb37, often used instead for cost reasons as the melting point difference is insignificant in practice. On slow cooling gives slightly duller joints than Sn63Pb37.

I have soldered connectors with gold plating and SMD ceramic capacitors with Sn60Pb40, Sn63Pb37 and Sn62Pb36Ag2 but I have never noticed an optical defective or circuit failure. The wikipedia refers that  "Rapidly dissolves gold and silver, not recommended for those" Sn60Pb40, Sn63Pb37 Vs Sn62Pb36Ag2. Maybe this is practically noticeable in high frequencies in level of loses?
Also, with a chance about the mention from wikipedia where "Sn63Pb37 - good for stainless steel", I would try to solder some stainless steel from time to time and some had not the perfect bonding and some others didn't solder at all. I read that for stainless steel is needed flux with phosphoric acid-based. Has anyone experience with stainless steel soldering?

[tooki]

Below are some of the solder wires that I have used.

I haven’t used their lead-free stuff, but I very much like the leaded Elsold. But I’m not aware of any retail distributors of it; I got mine from a company liquidation.

[tooki]

I have soldered connectors with gold plating and SMD ceramic capacitors with Sn60Pb40, Sn63Pb37 and Sn62Pb36Ag2 but I have never noticed an optical defective or circuit failure. The wikipedia refers that  "Rapidly dissolves gold and silver, not recommended for those" Sn60Pb40, Sn63Pb37 Vs Sn62Pb36Ag2. Maybe this is practically noticeable in high frequencies in level of loses?

No. As already explained to you multiple times (once by me, once in the wiki article cited), the danger is in dissolving away thin plating on ceramic. Once it’s dissolved away, there is no conductor left. It would also be a problem if soldering iron tips were made of silver or gold, but they are not.

Gold contamination makes leaded solder brittle*, so high-reliability applications (aerospace, military) specify that thick gold plating must be removed (either by rinsing in a solder pot twice, or by tinning with solder, then wicking it away) before making the joint. (And for SMD components, even thin gold plating must be removed.)

*technically, it does the same to lead-free, but the effect is much smaller so it’s normally ignored.

[jpanhalt]

For soldering stainless steel, that generally requires a highly active/acidic flux, and the fluxes I am familiar with have a halogen (usually chloride) in them.

Stainless, while quite resistant to corrosion, is very easily etched by acidic chlorides, like ferric chloride and HCl.  That has to do with the chloride more than pH.

Attachment = typical stainless flux for solder.

[2X]

I have soldered connectors with gold plating and SMD ceramic capacitors with Sn60Pb40, Sn63Pb37 and Sn62Pb36Ag2 but I have never noticed an optical defective or circuit failure. The wikipedia refers that  "Rapidly dissolves gold and silver, not recommended for those" Sn60Pb40, Sn63Pb37 Vs Sn62Pb36Ag2. Maybe this is practically noticeable in high frequencies in level of loses?

No. As already explained to you multiple times (once by me, once in the wiki article cited), the danger is in dissolving away thin plating on ceramic. Once it’s dissolved away, there is no conductor left. It would also be a problem if soldering iron tips were made of silver or gold, but they are not.

Gold contamination makes leaded solder brittle*, so high-reliability applications (aerospace, military) specify that thick gold plating must be removed (either by rinsing in a solder pot twice, or by tinning with solder, then wicking it away) before making the joint. (And for SMD components, even thin gold plating must be removed.)

*technically, it does the same to lead-free, but the effect is much smaller so it’s normally ignored.

Thanks for your reply and for your patience. I apologise because in your first post I didn't give the right attention at the word "leaching".

[2X]

Do you know if there is a a rule about what metals or metal mixture (like solder) dissolves other metals more/less or there it is more complicated and has to do with the exactly amount of the mixture of solder metals (like the eutectic mixture.. Sn63Pb37 is eutectic and Sn60Pb40 is not)?
Theoretically I beleive in order to have zero dissolving/leaching is for instance to apply an 100% Cu "solder" on copper wire or to apply an 100% gold "solder" to a gold plating pin etc. The wikipedia link decribes each solder about what dissolving/leaching, but without a percentage comparison or why each solder creates minimum or maximum (maybe it is not so simple).

One more thought about solder with silver; Silver has better electrical conductivity in respect to lead, but in so little percent (I don't know if there solder wires with higher silver percentage.. above 2%) of a solder wire I don't know if it makes any practical difference.

Ι post some links below about some terms that we used in posts if someone is unfamiliar with these and in my opinion are very important terms/procedures.

Solder alloys
https://en.wikipedia.org/wiki/Solder_alloys

Eutectic Solder
https://fctsolder.com/eutectic-solder/

Eutectic Point: Definition, Phase Transition, Eutectic System, Alloys and Uses
https://testbook.com/chemistry/eutectic-point

leaching in solder
https://en.wikipedia.org/wiki/Solder_alloys

Electrical Conductivity - Elements and other Materials
https://www.engineeringtoolbox.com/conductors-d_1381.html


Eutectic Solder Explained


What Is the Eutectic Point? | Soldering

[2X]

One more solder that I am using to solder push buttons at ribon cables with low melting point at 58°C.

https://www.chipquik.com/store/product_info.php?products_id=210001