Solder 63/37 okay for silver plated copper. or 2% silver needed

[TechnicsHiFiFan]

Hello, it has been sometime, ive posted, have to be more active 

I was caught up a few years ago with thinking higher silver content wire ( brands like Stannol 4% silver high melting point). Long story short, some of my speakers the crossovers have had problems with cold joints and some of my audio gear.

I switched to 60/40, just the Jaycar (Australian store like Radio Shack), solder which i thought was good. I think went to 63.37 which i find is the best.

I came across an article about how silver is absorbed into the solder, and is mentioned here and elsewhere. I always scrape and clean traces back to copper before soldering. so i can get direct contact with the surface.

Another interesting thought is how gold plated surfaces like terminals - silver plated copper, would the same apply as to copper on a trace

I am relative new to Eutectic solder , why i thought this was the best place to post.

I did buy only a small sample of the 2% silver.  I am wondering if i should get more or stick with the 63/37



Comparison - best joint maybe the 2nd from left  the non silver wire, wire gauge used `16 awg silver plated copper on old pcb board

notice solder wire solidfied on the non silver wire


whereas with silver content wire is not solidfied


Depending on the wire, is it possible the solidified wire is less likely to be break? would some silver desolve into the contact on the board? i am just wondering

Thanks  Sam aka Technics hifi fan

[uli12us]

The silver in a leadfree solder is needed to reduce the melting point. If you use leaded solder, you don't need silver.

[TechnicsHiFiFan]

Thank you for the reply and help.  Silver plated copper is fine with 63/37 if using on copper traces on a pcb.

[johansen]

I have some 2% silver, 60/38 iirc. Thr silver just makes it look nicer.

At work we have to use some 3.5% silver 96.5 sn solder for whatever reason i dont know.

Iirc 2% silver is probably not enough silver for the silver plated ceramic terminal strips in some applications.

[Wallace Gasiewicz]

The only special case for silver in solder that I can recall was in a specific Tektronix Scope. 
It was used there to supposedly avoid leaching silver from some part, I think it was a mount for something in the scope. 
I bought some thin jewelry silver plated wire that I use for small repairs. It solders really well using any lead solder I have.

[wraper]

Tin/lead solder with added silver was only needed for some exotic parts with terminals consisting of thin silver layer to prevent its quick dissolving in solder. Not a thing these days. Nor it's needed if it's a thick silver or silver plating on another base metal.

[David Hess]

Nothing special is required for soldering to silver, however 2% silver solder has the advantage of being much stronger making it less likely to fail in applications where mechanical stress is present, like inside of a loudspeaker.  See below about the Tektronix silver plated ceramic terminal strips.

Gold is a different matter.  Above a certain percent, gold forms a brittle intermetallic with tin so special measures must be taken when soldering to thick gold plating.  Typically the gold plating is removed before soldering.  Flash gold plating is thin enough that it will dissolve completely into tin containing solders so that this is not a problem.  Adding silver to the solder will not help with soldering to gold.

Iirc 2% silver is probably not enough silver for the silver plated ceramic terminal strips in some applications.

I think Tektronix used 4% silver, which was required to keep the silver from dissolving from the ceramic terminal strip leaving the soldered joint unattached.  2% silver is better than nothing when making repairs on these terminal strips.

[tooki]

Tin/lead solder with added silver was only needed for some exotic parts with terminals consisting of thin silver layer to prevent its quick dissolving in solder. Not a thing these days. Nor it's needed if it's a thick silver or silver plating on another base metal.

^^^ this

Early SMD components (like resistors and ceramic caps) had the thin silver termination.

Another place you see it is ceramic hybrid circuits, IIRC.

Regardless, it’s nothing one needs to worry about in normal PCB and wire use. Nor would I recommend scraping traces down to bare copper. If there’s significant tarnish, use an abrasive rubber eraser or a fiberglass pen to remove it. Otherwise just let flux do its job.

FYI, I don’t think Stannol’s flux cores are particularly good, so you may be happier with another brand, like Kester. Kester 44 is a superb flux core option for leaded — the 63/37 Kester 44 is my favorite solder.

[TechnicsHiFiFan]

Hello
Thank you all so much for the help and advice
So sorry for the super late reply.  My hobby was put on hold. I stuck with the 63 37, though I have the 2% silver also, use it on interconnects etc, and crossovers as David mentioned.  Both flow well and yes, the tiny bit of silver, there is still some absorbsion of the silver plating but gives a nice solid connection, both of the solders.
 Noticed Tooki mentioned Stannol, I will use this brand next time, as here in Australia i can get it quite cheaply and in a small size for smds etc..  I looked up the Tektronix Scope.  Wallace and i can see, it has just the plating of silver only, if i am correct.

[wraper]

Noticed Tooki mentioned Stannol, I will use this brand next time, as here in Australia i can get it quite cheaply and in a small size for smds etc..  I looked up the Tektronix Scope.  Wallace and i can see, it has just the plating of silver only, if i am correct.

Tooki said it's not good, and I completely agree with him after using a few types with different flux cores.

[tooki]

Noticed Tooki mentioned Stannol, I will use this brand next time, as here in Australia i can get it quite cheaply and in a small size for smds etc..

Well no, you brought up Stannol in the original post. I commented that I do not like it. I mean, it’s not the worst, but there’s better out there, like the Kester 44 I mentioned.