Solder - unleaded or classic Sn60Pb38Cu2?

[Shefffield]

Hello, forum!

I'm not really good at soldering. In order to maximize my chances for good, reliant connections I still think that using leaded solder makes it a lot easier.

As far as I know, it is still legal for private users (here in Europe) to buy and use leaded solder. Where to purchase it is the next question though..

What are your experiences and recommendations?

 

[valerianf]

Lead solder is used for medical devices because of a better reliability.
However for home repair lead free solder is far sufficient.

 

[mightycicadalord]

I've always just bought whatever the local stores have which is usually 60/40 tin/lead.

 

[alex-z]

Unleaded isn't hard to make good connections with. Just follow best practices such as:

1. Clean the surfaces for soldering with high concentration isopropyl alcohol.

2. Tin the tip of the soldering iron.

3. Heat the wire you are soldering, not the solder itself.

4. Heat the joint until the solder is a shiny pool. Remove the iron slowly.

5. Use an iron with adjustable temperature and set it appropriately. Even small tasks I never use under 400ºF, 600+ for stuff like inductors which have a lot of thermal mass.

 

[somebodyelse]

Children manage to make decent joints with lead free solder and basic irons during learn to solder sessions at maker faires and similar, so don't worry too much about the type of solder. The method is more important. Find a good guide like the adafruit one, or perhaps more than one guide if they don't express it in a way that's clear to you.

The usual international suppliers should be reliable - RS, Farnell, DigiKey, Mouser. I've not used conrad.de but they look reasonable too.

 

[Lambda]

The stuff with lead is way better.
You don't need toxic and corrosive flux for the Lead based solders.
So it is actually saver to work with (as long as you don't lick it)

Results are always mush better. and they more reliable over long therm.

The lead free stuff is prone to cracking over time and with temperature cycles.
and it is susceptible to "tin pest" and "whiskers".

Where to purchase it is the next question though

https://www.mouser.de/c/tools-supplies/soldering/solder/?alloy=Sn60%2FPb40&description%2Ffunction=Flux%20Core%20Wire&product=Solder&type=Wire%2C%20Rosin%20Core&sort=pricing

 

[egellings]

Lead-free solders also have a higher melting temperature than lead-containing solders do. That can be hard on PCB traces if someone is not skill with wielding an iron. The solder also sets with a dull finish that looks for all the world like a cold solder joint to the uninitiated. For home projects, I cannot see using lead free because usage rate will be small compared to manufacturing operations.

 

[levimax]

+ 1 lead solder all the way for DIY projects and repairs, much easier to work with and more reliable long term . I use "eutectic" solder which is 63% tin and 37% lead.... not a big difference from 60% / 40% but supposedly the ideal mix that melts at a lower temperature. Works well for me.

Amazon has it: https://www.amazon.com/s?k=Kester+6...ix=kester+63+37+solder,aps,120&ref=nb_sb_noss

 

[617]

I think you're over thinking it. Just practice a little first, and use crimped connections wherever possible. The last passive speaker I built had no soldered connections.

 

[Sal1950]

Just like gasoline, the leaded version always works better.

 

[SIY]

+ 1 lead solder all the way for DIY projects and repairs, much easier to work with and more reliable long term . I use "eutectic" solder which is 63% tin and 37% lead.... not a big difference from 60% / 40% but supposedly the ideal mix that melts at a lower temperature. Works well for me.

Amazon has it: https://www.amazon.com/s?k=Kester+63+37+solder&crid=1GY8VDDMNQSK6&sprefix=kester+63+37+solder,aps,120&ref=nb_sb_noss

The other advantage to 63/37 is that it freezes faster after the iron is removed, minimizing the chances of a cold joint. When I can find it, that's what I prefer using.

 

[Doodski]

I've worked extensively with high temp lead free solder for fabricating high temperature downhole tools and when servicing electronics I used leaded 63/37 solder. I advise to use leaded solder. It flows better, requires less flux and is more gentle on circuit boards too.

 

[Doodski]

The stuff with lead is way better.
You don't need toxic and corrosive flux for the Lead based solders.
So it is actually saver to work with (as long as you don't lick it)

Results are always mush better. and they more reliable over long therm.

The lead free stuff is prone to cracking over time and with temperature cycles.
and it is susceptible to "tin pest" and "whiskers".

https://www.mouser.de/c/tools-supplies/soldering/solder/?alloy=Sn60%2FPb40&description%2Ffunction=Flux%20Core%20Wire&product=Solder&type=Wire%2C%20Rosin%20Core&sort=pricing

I am surprised to see anybody here is aware of whiskers. I was reading a NASA website many years ago and found a entire section dedicated to whiskers.

 

[AnalogSteph]

BTW, have people figured out why Pb seems to suppress tin whiskers yet?

AFAIK, with lead-free solder you can only ever have two of reliable, cheap and easy to work with. And then there's the issue of higher temps, making flux fumes more toxic. Combined with initially more issues with bad solder joints (more discarded electronics) and silver migration shorting out easily cracked MLCC capacitors, the overall environmental benefits of Pb-free solder seem at least dubious.

 

[JeffS7444]

For ROHS-era gear, I use ROHS (lead-free) solder, and in particular, this Sn/Ag/Cu/Sb blend:
https://www.sparkfun.com/products/10243
For older gear, I use Sn/Pb/Ag

 

[pjug]

I hated ROHS soldering at first, but used to it now. I burn through a lot more soldering tips with lead-free. I use SAC305.

https://www.mouser.com/ProductDetail/AIM/14315?qs=M7ZD%2F0QMIQxsLEO1q4Y%2FhQ%3D%3D

 

[MakeMineVinyl]

I never use lead free solder. The regular 60/40 stuff is far easier to work with. That might not be politically/environmentally/biologically correct, but that's the way it is.

 

[mansr]

There is tin/bismuth solder with a melting point of 138 °C (eutectic). It's nice for avoiding heat damage when prototyping and a lot of board rework is expected.

 

[sergeauckland]

I never use lead free solder. The regular 60/40 stuff is far easier to work with. That might not be politically/environmentally/biologically correct, but that's the way it is.

Although I try as much as possible to be environmentally sensitive, when lead-free solder was first mandated, in case it was hard to come by in future, I bought 1Kg of 60/40 which I thought would see me out. I had to make up some 3000 connections for our local radio station, and many of them would be in hard to access places, so wanted maximum reliability. If 60/40 was still good enough for space and medical equipment, I figured it would be good enough for me. I fortunately still have a fair bit left.

Repairs especially are easy with 60/40 although to be fair, I've never tried lead-free, just know it's a pain to get it to flow to remove faulty parts. As long as 60/40 remains legal, I'll continue to use it.

S

 

[audio2design]

Even with the best lead-free solder, leaded solder is definitely easier and better. It just is what it is.

My understanding is the tin does a pretty good job of keeping the lead from leaching so the health risk is not very high. For most clients and anything in production now it is all lead free.

If doing lead free, spend the extra money for solders with more than tin/copper, and get ones with more flux.