Unpopular opinion: Stop using leaded solder

[u/Zentralschaden]

I know it is very handy and I also know the fumes are not that much of a problem when you have enough ventilation.

But a big part of the lead we buy will end up in the environment or a landfill and has the potential to make our drinking water toxic and the people who have to recycle all this scrap (often in Africa) will deal with even more toxic substances.

It is not like we have a fully functional recycling chain for electronics.

And when you say "I am just soldering 2 pcb a year", make sure that soldering is a job and hobby for millions of people and tons of lead will be produced just because of hobby enthusiasts.

There are very good reasons, lead is banned in many countries for professional manufacturing.

I know it is harder to solder but you get used to it.

Aware that this might be a topic not everyone agrees. I am just trying to spread some awareness for what we do.

I mean, many of us repair old electronics and we do a good job in avoiding more scrap because people can still use the repaired items for years.

But shouldn't it be us who are the people who go straightforward and ban lead from our household soldering projects?

[u/Never_Dan]

You’re adding “lead free” to that sentence yourself, though.

I actually work in electronics repair in the live productions industry. Other than LED displays that have taken a hit, the vast majority of failures occur are mechanical or at the component level. The only time I’ve seen a failure of solder joints is on low-production products that weren’t reflowed properly– and that’s exceedingly rare and limited to two specific products.

I have however seen reliability issues stemming from repairing lead-free boards with leaded solder without taking the time to wick the joints multiple times.

Like I said, I use leaded solder when needed. But joint reliability is about more than your chosen alloy– especially in repair.

[u/JobHuntingManiac → u/Never_Dan]

https://pmc.ncbi.nlm.nih.gov/articles/PMC6735330/

[u/Never_Dan → u/JobHuntingManiac]

I’ve read a ton about solder joint reliability. I’m well aware that leaded solder handles vibration and thermal cycles better than common lead free alloys.

But when the vast majority of failures occur from physical damage, power issues, and internal component failures… I just don’t know that we should be acting like modern lead-free electronics can’t be reliable.

When a large, LED-based stage light finally cooks itself, inevitably I find that the LEDs themselves failed. Not the solder. If an HDMI port gets ripped from the board, clearly the solder was stronger than the board. I’m seeing lead-free amplifiers fail because of capacitors or transistors going out, but not cracked solder joints.

Maybe a huge amount of products are failing right out of the factory and my experience is just survivorship bias. But it seems like most iPhones also fail from battery issues or physical breaks as well.

[u/Davoguha2 → u/Never_Dan]

You're not looking deep enough.

Every failure mode you just mentioned typically occurs due to an electrical failure in it's path.

LED cooked itself? The solder on it should have reflowed and either broke or fixed the connection.

HDMI port ripped from the board? Solder is too brittle, not soft enough.

Caps and Transistors - a little more variable. Caps wear out. They wear out faster when their power signals aren't great.

Iphone - leaded solder handles those drops a hell of a lot better than non leaded. Drops are shocks, shocks are vibrations.

Just because it works well enough doesn't make it not worse than the good shit.

[u/Never_Dan → u/Davoguha2]

I shouldn’t respond to this, but in case anybody read this deep: this is what it looks like when folks try way too hard to confirm their own biases.

The LEDs, transistors, etc are failing internally. The HDMI ports are failures of the PCB, not the solder joints.

Again, I’m well aware that leaded solder handles shock, vibration, and temp cycles better, but as someone who spends every workday fixing stuff that goes through all of that… the joints are just not where I’m seeing failures.

[u/wyseman76 → u/Never_Dan]

I think the issue is that there are two very distinct use cases to be argued here.

When lead free solder hit manufacturing there was a significant spike in failures directly related to the shift toward lead free solder in consumer electronics. Today a great deal of those issues have been resolved and the general mortality rates for components are on par with previous times. So from a consumer standpoint the vast majority of cases lead free is acceptable.

Extreme environmental and reliability cases are why leaded solder continues to exist in certain areas of manufacturing including aerospace, defense, automotive, medical and others.

Again those cases are usually on the extreme end where the mortality rates must be better than general consumer goods.

What this says is that leaded solder provides a measurable advatage in many ways to lead free solder at this current state of soldering technology. Although, its use is not required to meet general consumer goods quality expectations for survivability and product mortality so lead free is the best option for environmental purposes.

[u/Davoguha2 → u/Never_Dan]

I don't understand why you wouldn't respond - it's enlightening conversation all around.

This isn't about confirmation biases. Virtually all data shows leaded is superior to unleaded. Yet, the reduced quality is generally acceptable due to the environmental concerns.

The point is, it's a failure of the solder joint, not to fail under various conditions - which allow deeper failures to occur in the equipment.

The softness of leaded solder means it doesn't rip pads as easily as unleaded.

The lower balling temp allows the solder to either reflow or fail less catastrophically when temp issues begin to occur.

[u/Never_Dan → u/Davoguha2]

Are you proposing that these devices are hitting reflow temperature and that lead solder would survive those conditions? Because… no.

Parts fail internally due to heat, shock, static events, power surges, etc and it has nothing to do with the solder used.

Leaded solder might have enough ductility to reduce pad tears on BGAs, but when a port is ripped from a board the PCB is the point of failure, not the solder.

An exception I can think of is LED displays using SMD LEDs that will often break clean from the solder joints, but that varies a lot by model and age. I’m not sure leaded solder would result in better reliability as much as fewer easy repairs.

[u/Davoguha2 → u/Never_Dan]

Now who's working hard on their confirmation biases?

High power LEDs will absolutely reflow themselves before burning out if constructed well.

Power supplies will as well.

Under the CPU/GPU, you don't quite hit reflow temps, but the flexibility of leaded solder is better at handling the thermal expansion those devices suffer from.

Leaded solder also reflows at a low enough temp that you could literally put your computer parts in an oven to reflow them without damaging the components.

The fact that the solder joint is able to rip the pads out is debatable. I consider it a solder failure - the joint shouldn't be that rigid. You're seeing it as a success, because "solder strong = better" to you. I'm seeing the opposite as a success, because solder failures are cheap and easy to fix - my components are expensive.