Soldering ..is lead still preferred over lead free? Interesting article

[Richard_James]

Found interesting article about lead free vs lead based.
Looks like need to stay with leaded soldering

What are the disadvantages of lead-free solder vs. lead solder? - Quora

Basically lead free soldering was responsible for billion dollar satellite failures. Tin whiskers caused it. Some gentleman discovered the cause and got a prize for it


I have a variable temperature solder machine. Goes up to 1000f

What are best lead based solder wires with flux substance inside the wire.

And whats the optimal temperature to solder lead.

 

[ubergeeknz]

63/37 tin/lead is nice to solder with, known as Teutonic, it doesn't have a "plastic" phase like 60/40.

I have enjoyed using Kester 44 63/37 for a while now, it is a good rosin, I find it goes on easy and flows well into the joint no matter what.

Temperature, depends a bit on the mass of your tip, what you're working on, and seemingly pure personal preference (hot and fast vs low and slow) going by the range of temps I've seen suggested. I usually set my iron at 340°C

 

[wiseoldtech]

I use Kester "44".
Been using it for decades.


Lead solder has been around forever, has held up well forever, and has been the technician's best friend forever.
The proof is in the millions of products going back to the early 1900's.


Screw that lead-FREE crap.

 

[nenad88]

Using these 2 but 1mm versions.

[IMGDEAD]https://mmc.bolha.com/2/image/208952/210774/Zica-za-spajkanje-0-6mm-1kg-Elsold-L-Sn60Pb_590ca9720f9c5.jpg[/IMGDEAD]

Very happy, w.german quality.

 

[JonSnell Electronic]

I use Kester "44".
Been using it for decades.


Lead solder has been around forever, has held up well forever, and has been the technician's best friend forever.
The proof is in the millions of products going back to the early 1900's.


Screw that lead-FREE crap.

Unfortunately if one uses lead solder, 60/40 etc, on SMD components, the lead leeches the tin plating contacts from the SMD components causing reliability issues later on.
Tin does however grow 'fingers' like crystals and in many BGA installations I have examined when faulty returns from major manufacturers using Tin instead of Lead solders, the 'fingers' caused the failure by way of short circuits between the balls and indeed the legs of 200 pin devices and larger, especially on video processing ICs.

Most manufacturers have gone back to leaded solder in BGA and high density SMD devices but still use tin based solders for standard SMD components.

 

[Mooly]

63/37 tin/lead is nice to solder with, known as Teutonic, it doesn't have a "plastic" phase like 60/40......

Teutonic?

 

[arg_]

eutectic

that's greek to me and so it works

 

[ubergeeknz]

eutectic

that's greek to me and so it works

Yep that's the word [emoji2357] close enough right [emoji23]

 

[wiseoldtech]

Unfortunately if one uses lead solder, 60/40 etc, on SMD components, the lead leeches the tin plating contacts from the SMD components causing reliability issues later on.
Tin does however grow 'fingers' like crystals and in many BGA installations I have examined when faulty returns from major manufacturers using Tin instead of Lead solders, the 'fingers' caused the failure by way of short circuits between the balls and indeed the legs of 200 pin devices and larger, especially on video processing ICs.

Most manufacturers have gone back to leaded solder in BGA and high density SMD devices but still use tin based solders for standard SMD components.

In that case, appropriate measures need to be taken.
Sealing/coating the boards such as with moisture-proofing spray.


However, I rarely get into SMD component level work since I focus on vintage restorations.
The "new SMD stuff" usually got board replacements.

 

[coolnose]

Well well, the both solder from post 4 are definitely "teutonic" one seems to be eutetic as well...

 

[Bigun]

I've tried both. The lead free is harder to work with, the fumes are nasty in some cases. I've stuck with leaded.

 

[RJM1]

@wiseoldtech

Conformal Coating was tried and did not work.

https://nepp.nasa.gov/whisker/refer...-of-tin-whiskers-and-conformal-coat-study.pdf

 

[Jakob2]

<snip>

Basically lead free soldering was responsible for billion dollar satellite failures. Tin whiskers caused it. Some gentleman discovered the cause and got a prize for it

We had recently a discussion in the blowtorch thread about the various leadfree solder alloys in use and one of the linked papers was especially addressing the tin whisker problem. While the reasons for the whisker formation are still unknown, it is known that the whisker formation depends strongly on the altitude, therefore satellites should be more prone to this problem.

Otoh we started using leadfree tin/silver alloys around 1993 (afair) with normal throughole partes with according normal clearances and up to now haven't seen a defect due to tin whiskers.

Based on the available data probability is much higher if using just such an alloy for fine pitch smd parts over a longer time span.

Due to the higher temperatures leadfree soldering needs a bit more care and some training (to get a fealing for a good joint, as a good leadfree solder joint might look like a cold solder joint when using lead solder) but is no witch craft.
Wear of solder tips is higher, though.

 

[Oneminde]

My contribution to your question

The way forward (Soldering).

 

[Refugee1]

Lead free solder had caused various problems with cars.
Some have failed short circuit on the accelerator control while others especially non stick shift models that have been left running have ended up driving themselves round in circles.
The manufacturers only use lead free so that they are allowed to show a vanity logo on there products.
Aerospace was the first industry to stop using lead free on very good safety grounds.

 

[Max Headroom]

I well understand the whisker/reliability issues of some lead free solders in fine pitch pcb/components but in the scope of audio with TH and discrete smd layout I consider there is no real problem with 99.3Tin/0.7Copper alloy.
Yes this alloy is trickier to use than Lead solder and higher mass solder tip is required but I routinely solder perfect looking joints using the above LF alloy.
I also find this LF solder to be more pleasant sounding than lead alloys which cause an unpleasant damping and signature ime/imo when used on pcbs, interconnect cables and speaker crossover and driver connections.
One has to closely audition same/similar circuits using different alloys to gain an appreciation of the sonic differences that may not be heard on first listen but after a few AB trials the ears 'get it' and there is no unhearing the differences.
Many of us sweat over resistor types and capacitor types, cables, connectors etc etc etc.....solder type is just another ingredient in determining the sonics/signature of audio systems and like component types solder type is not to be ignored imo.

 

[wiseoldtech]

Max's comments about the quality of sound regarding solder types is obviously a joke, people.
I suspect that drugs are the underlying reasons there.

 

[Monte McGuire]

Kester 44 flux makes my throat hurt, and is not as effective as more modern fluxes. It actually has a non-zero halide content (0.44%, hence the name '44') but oddly enough, it's a no-clean flux that has been proven to be non corrosive despite its halide content. Still, you can get a range of alloys, and a range of fluxes, so for 63/37 alloy, I prefer Kester 245 flux. It's also a no-clean flux, it has lower odor and lower irritation than 44, and it also has a greater wetting capability than 44. So, it's better all around - you'd expect that from something designed in this century

The Kester part number for 0.031" wire with 245 flux is 24-6337-8800 (Searching...). I've become a fan of 0.015" diameter (0.40 mm) wire, as it gives me better control over the fillet, but I work on smaller stuff anyway. Kester also sells that with a 245 flux (part number 24-6337-8806, Searching...) and I use a bunch of that. In the US, Techni-Tool has a good fresh stock and good prices on Kester products.

For SMD, I use leaded paste since it reflows at a lower temperature and has greater wetting capability. I've been pretty happy using Kester EP256 with a 6 mil stencil, an infrared pre-heater, and a hot air wand. It's a 63/37 alloy with a nice flux and a useful particle size for stencil use. I've been able to print footprints for 0.5 mm lead pitch components (0.3 x 0.75 mm pads) reliably, as long as I get the screening right and do the proper temperature cycle with the preheater.

Someone mentioned earlier that lead solder leaches tin out of SMD components causing failures, but I don't think that's correct. SMD components frequently have nickel barriers on their solderable surfaces to prevent copper from being leached into the joint, and any surface coating on top of the nickel barrier is purely to assure solderability. The typical tin finish on many components is not a problem with any lead free alloy or 63/37.

Gold however will be a problem as it will form an intermetallic with tin or tin/lead solder alloys and makes the solder joint brittle, unless it is washed off first, so maybe that's what you're thinking of? I have been using leaded paste for SMD for several years now and have had zero problems with joint reliability that I can attribute to any alloy. The standard problems like bad footprints, or an improper thermal cycle are the usual culprits, but once a joint has been made successfully, it's stable with all manner of components that use tin finishes.

 

[Max Headroom]

Max's comments about the quality of sound regarding solder types is obviously a joke, people.
I suspect that drugs are the underlying reasons there.

If you read my post again properly you will understand that no I am not joking in the slightest, and apart from the Tramadol I am currently taking for a fractured/crushed/wedge shaped vertebra I am likely straighter and clearer than you have ever been.
You call yourself 'wiseoldtech', I have worked alongside plenty of sour/negative/cynical old techs just like I sense you are deep down, this is my observation and not intended as insult like your post clearly is.
I don't believe hearsay like solder and wire/cable make no differences unless I prove for myself, in these above examples I find that there are indeed audible differences that can make or break an otherwise good system, just like capacitor or resistor types can make or break a system.
The theory we were taught in tech school is elementary theory and does not attempt to explain fine points of material behaviours.
I have a small glass vial that fits car cigarette lighter sockets perfectly.
When this vial filled with particular ingredients and is plugged into such sockets the car sound system changes (for the better) for every car this has been trialled on.
Note there is no electrical contact, only proximity or field effects of some sort at work, perhaps you might like to explain the mechanism, I would be most grateful if you were to do so and I would be pleased to reward you handsomely when I take this and/or associated devices to market.
This is sincere offer, the rest is up to you.

Dan.

 

[rsavas]

Good info Monte, I use AIM glow core no-clean, 63/37 alloy. I am very happy using it. I agree using 0.015" diameter (0.40 mm) wire solder for most smt work.

Dan, I just can not figure out why you think so.

"I also find this LF solder to be more pleasant sounding than lead alloys which cause an unpleasant damping and signature ime/imo when used on pcbs, interconnect cables and speaker crossover and driver connections."

Not going to argue the point but it is hard to understand why, with no supportive measurements to back such a claim.