Why not lead-free

[p.larner]

I dont know about in the u/s but in the uk all it seems to have done is push the prices of 60/40 leaded solder thru the roof.

[peter-h]

ROHS is complete total 100% BS. One is asked to certify that one's product does not contain any of about 200 substances (lead being just one) and nobody on earth can possibly be sure of that. So it's all about paperwork. Like Conflict Minerals etc.

The old leaded solder went from £5 (500g) to about £40
https://www.rapidonline.com/r-tech-856861-solder-wire-60-40-22swg-0-7mm-500g-reel-85-6861

At work we have evaluated many samples of unleaded for hand soldering and most are poor. In general a much hotter iron is needed to make them work at all. The best by far is from Almit, which is standard SAC305 but with a decent flux which is actually the biggest problem, and that one is about £70. But it solders as well as the old 60/40 (above).

For SMT I use leaded paste for prototyping because it flows far better. For production, SAC305 is used and seems to work ok if the contractor has proper (expensive) equipment.

ROHS has cost billions and it's been wasted. No evidence of population health rish due to solder used in electronics.

[Andy Chee]

ROHS has cost billions and it's been wasted. No evidence of population health rish due to solder used in electronics.

I suppose the health risks come from the disposal of the electronics item, rather than product manufacturing and daily consumer use.

Sure, Western countries typically ship their e-waste to poorer countries for recycling, but that doesn't mean manufacturers are absolved of health responsibilities.

[coppice]

ROHS is complete total 100% BS. One is asked to certify that one's product does not contain any of about 200 substances (lead being just one) and nobody on earth can possibly be sure of that.

These days its not that hard for an equipment maker, although you need to be cautious about the numerous variants of a component, some of which may not be compliant. Most parts are now designed to be RoHS compliant, and you can get a simple statement from the vendor which states they are RoHS compliant. You don't need to go into all the details most of the time. The hard work was with the component makers, who had to do a lot of work to figure out how to make things work well, at decent prices, with compliance. I assume those costs are coming down now that the RoHS compliant market has somewhat stabilised.

[coppice]

Sure, Western countries typically ship their e-waste to poorer countries for recycling, but that doesn't mean manufacturers are absolved of health responsibilities.

I think its unclear how much gets shipped and how much goes into local landfills or incinerators. If a small appliance fails it usually just goes into the general household waste. Its only the big stuff that gets separated and treated as e-waste. So, what are the relative sizes of the large appliance and small appliance categories?

[tooki]

“Slower to use”?!? What do you mean?

No matter what iron, no matter what solder, in electronics the goal for nearly all joints is to be in and out within about 3 seconds. If your iron (in combination with a given tip) can’t do that at any reasonable temperature setting, it’s not suited to the job, not just “slow” to use, and must not be used.

As I see it, the benefits of modern irons are 1. ready to use within seconds, and 2. let you get away with a smaller thermal mass in the tip and heater, allowing for smaller irons. But not speed of soldering operations themselves.

Why do you think employers are happy to pay for expensive irons for cheap labour to use? Its all about speed. Who can afford to pay people even low hourly rates at 3s a joint? That's an eternity on a production line. With lead solder and a very cheap iron experienced people solder typical through hole and SMD joints at a very high rate with lead solder. Give them lead free solder and they slow down, as it takes time to get to the higher temperatures needed. Give them things like JBC irons and their speed comes back. If the product has numerous high current joints, these modern irons are a big plus for both lead and lead free soldering, but their key benefit is with lead free solder, to recover the productivity loss higher temperatures bring with traditional soldering irons.

Oh puh-leez… 🙄

One thing I was trying to illustrate, but clearly went right over your head, is that fast response in the iron isn’t the only way to achieve operator speed. The 3 seconds isn’t a target, by the way, it’s a limit.

Professional soldering stations have been around, and have been expensive, since long before lead-free, so that argument is clearly nonsense. Employers pay for good equipment because it ensures process compliance and reduces downtime.

Yes, lead-free requires more heat. Nobody disputes this. But pumping in that heat quickly does not mandate a cartridge-heater iron. One way is higher tip temperatures. Another way is larger tips. As long as the control loop can keep up, it’s fine. And there’s nothing to indicate that older irons struggled to keep up, unless pushed beyond their limits. (And an iron being pushed beyond its limits is just as possible with a larger joint.) Other solutions include resistance soldering, which I’ve seen videos of in extremely high-speed production.

If a production line’s productivity dropped with lead-free until they upgraded their stations, then the stations were inadequate for those joints with lead-free solder. But they could just as well have upgraded to a better non-JBC iron with more power. And — and to reiterate, this is my main point — those same “inadequate” stations would still be adequate for other lead-free work with smaller joints. No soldering station is sufficient for all lead-free work (nor for all leaded work), so I vehemently disagree with the original premise that there are special soldering stations for lead-free. There aren’t, there are simply more powerful, more responsive stations, which will improve the situation any time one is at the thermal limits of their equipment, regardless of whether the source of that need is different solder or larger joints.

[Andy Chee]

Sure, Western countries typically ship their e-waste to poorer countries for recycling, but that doesn't mean manufacturers are absolved of health responsibilities.

I think its unclear how much gets shipped and how much goes into local landfills or incinerators. If a small appliance fails it usually just goes into the general household waste. Its only the big stuff that gets separated and treated as e-waste. So, what are the relative sizes of the large appliance and small appliance categories?

And just like the RoHS auditing and paperwork, there is now an emerging discipline of documenting e-waste movements.  This data may be used by governments to tax tech companies  for intentionally manufacturing and profiting from unreliable products with a short consumer lifecycle (unreliability ironically might be attributable to lead-free solder!)

[tooki]

RoHS chips are more expensive when I shop. May as well buy the non-RoHS chips and use leaded solder with minimum required temperature that is cheaper (in US) and easier to work with.

Where are you shopping that even carries old non-RoHS chips?!? All the big distributors sold through their non-RoHS inventory years ago.

The problem with RoHS is politicians with unrelated work experience think kids unscrew their toys and lick the contacts. Lead poisoning is primarily a concern in children due to their small size and development. Too bad they didn't consider the actual bioavailability. Leaded gasoline that people breathed in, that was a problem and I'm sure lobbyists did the Thank You For Smoking treatment to deny.

RoHS was never about immediate consumer hazard like kids licking it, but about reducing environmental contamination as a result of disposal. When RoHS was concocted, CRTs were still the overwhelmingly dominant type of large display device, and every CRT TV and computer monitor contains several kilos of lead, thanks to the leaded glass used in the tube itself. The amount of lead in the solder was negligible, all things considered. I don’t think it was obvious that eliminating lead solder would a) be as difficult as it was initially, and b) accomplish so little, since CRTs would soon be supplanted anyway.

Leaded gasoline was a scourge indeed. The lead was dispersed in the exhaust, depositing all along roads. (While handling leaded gasoline could also introduce the lead to the body, that wasn’t a significant exposure route, generally speaking.)

[coppice]

RoHS chips are more expensive when I shop. May as well buy the non-RoHS chips and use leaded solder with minimum required temperature that is cheaper (in US) and easier to work with.

Where are you shopping that even carries old non-RoHS chips?!? All the big distributors sold through their non-RoHS inventory years ago.

The last time I checked there were still quite a few non-RoHS compliant devices being made, for industries where there are exceptions. Some medical applications, for example. That's why I said a few messages back that auditing your product for hazardous materials is pretty straightforward these days, but you do need to be cautious that you are actually using a RoHS compliant variant of a part.

[tooki]

RoHS chips are more expensive when I shop. May as well buy the non-RoHS chips and use leaded solder with minimum required temperature that is cheaper (in US) and easier to work with.

Where are you shopping that even carries old non-RoHS chips?!? All the big distributors sold through their non-RoHS inventory years ago.

The last time I checked there were still quite a few non-RoHS compliant devices being made, for industries where there are exceptions. Some medical applications, for example. That's why I said a few messages back that auditing your product for hazardous materials is pretty straightforward these days, but you do need to be cautious that you are actually using a RoHS compliant variant of a part.

Sure, but those parts are typically not stocked by the kinds of distributors that sell to hobbyists (this is the beginners subforum, after all), since those customers are typically going to be ordering directly from the manufacturer.

[coppice]

RoHS chips are more expensive when I shop. May as well buy the non-RoHS chips and use leaded solder with minimum required temperature that is cheaper (in US) and easier to work with.

Where are you shopping that even carries old non-RoHS chips?!? All the big distributors sold through their non-RoHS inventory years ago.

The last time I checked there were still quite a few non-RoHS compliant devices being made, for industries where there are exceptions. Some medical applications, for example. That's why I said a few messages back that auditing your product for hazardous materials is pretty straightforward these days, but you do need to be cautious that you are actually using a RoHS compliant variant of a part.

Sure, but those parts are typically not stocked by the kinds of distributors that sell to hobbyists (this is the beginners subforum, after all), since those customers are typically going to be ordering directly from the manufacturer.

People ordering as hobbyists have even bigger issues with non-RoHS compliant parts than professionals. Much of what is offered to that market was made before RoHS became an issue. Its also stuff so hard to solder, due to long term tarnishing, that its a bigger PITA to solder than lead free parts.

[coppice]

Professional soldering stations have been around, and have been expensive, since long before lead-free, so that argument is clearly nonsense. Employers pay for good equipment because it ensures process compliance and reduces downtime.

Name one expensive soldering station that was getting serious traction in the marketplace before lead free solder was a requirement? A basic Weller or Hakko was the norm pretty much everywhere.

[tooki]

Professional soldering stations have been around, and have been expensive, since long before lead-free, so that argument is clearly nonsense. Employers pay for good equipment because it ensures process compliance and reduces downtime.

Name one expensive soldering station that was getting serious traction in the marketplace before lead free solder was a requirement? A basic Weller or Hakko was the norm pretty much everywhere.

Pace, Metcal, fancier Weller, Ersa, Ungar, American Beauty (esp. for resistance soldering), …

And I think maybe you forget just how expensive stuff used to be. In 1979, $60 got you a Weller WTCPN, a basic magnestat station with no adjustability, for the equivalent of $225 today. It only went up from there.

Pace, for example, has never been cheap, but it’s ubiquitous in military and aerospace (Pace was founded by a military veteran, after all). They’ve been around for over 60 years, and many of their systems cost thousands.

The point is, companies back then weren’t using no-name Chinese crap, they were using name-brand equipment that wasn’t cheap.

I also think you’re ascribing to lead-free all of the increased demands in modern soldering, when in fact the work itself has also changed. 40 years ago we didn’t have nearly as many multilayer boards, with their heat-sucking internal layers. We do a lot more SMD, and we do power SMD packages that didn’t even exist then.

[tooki]

People ordering as hobbyists have even bigger issues with non-RoHS compliant parts than professionals. Much of what is offered to that market was made before RoHS became an issue. Its also stuff so hard to solder, due to long term tarnishing, that its a bigger PITA to solder than lead free parts.

Hobbyists don’t only order from shitty surplus vendors. Digi-Key has always been for hobbyists (that was what they were founded to do) and they certainly don’t focus on old stock.

[coppice]

Professional soldering stations have been around, and have been expensive, since long before lead-free, so that argument is clearly nonsense. Employers pay for good equipment because it ensures process compliance and reduces downtime.

Name one expensive soldering station that was getting serious traction in the marketplace before lead free solder was a requirement? A basic Weller or Hakko was the norm pretty much everywhere.

Pace, Metcal, fancier Weller, Ersa, Ungar, American Beauty (esp. for resistance soldering), …

And I think maybe you forget just how expensive stuff used to be. In 1979, $60 got you a Weller WTCPN, a basic magnestat station with no adjustability, for the equivalent of $225 today. It only went up from there.

Pace, for example, has never been cheap, but it’s ubiquitous in military and aerospace (Pace was founded by a military veteran, after all). They’ve been around for over 60 years, and many of their systems cost thousands.

The point is, companies back then weren’t using no-name Chinese crap, they were using name-brand equipment that wasn’t cheap.

I also think you’re ascribing to lead-free all of the increased demands in modern soldering, when in fact the work itself has also changed. 40 years ago we didn’t have nearly as many multilayer boards, with their heat-sucking internal layers. We do a lot more SMD, and we do power SMD packages that didn’t even exist then.

Have you lost the plot? I didn't refer to any cheap Chinese tools. I referred to Hakko and Weller. The expensive Wellers just did what the Curie point ones did, but with a knob to set the temperature. The expensive Hakkos were similar. I used to be a mass murderer, but I never saw a Pace iron in the defence industry. Maybe they were just in the US until recently. Everything I've seen built in the defence industry has been built with a Weller Curie point iron. We assembled 8, 16 and 22 layer boards 40 years ago with those irons, through hole and SMD. The only ones that gave any trouble with lead solder were where someone had messed up the thermal lands. Those had to be fixed whether you used the existing irons, or something that could push out more heat, for reliability reasons.

Metcal was very niche before lead free solder become the norm. Ungar I am only aware of for cheap and nasty products. Ersa has never seemed special. I had never heard of American Beauty before your post.

Note that the need for highly response irons was so small before lead free solder that the RF heated iron was developed and patented by Hakko well before Metcal, but not brought to market until recently, because they couldn't find a market for it.

[tooki]

Name one expensive soldering station that was getting serious traction in the marketplace before lead free solder was a requirement? A basic Weller or Hakko was the norm pretty much everywhere.

Pace, Metcal, fancier Weller, Ersa, Ungar, American Beauty (esp. for resistance soldering), …

And I think maybe you forget just how expensive stuff used to be. In 1979, $60 got you a Weller WTCPN, a basic magnestat station with no adjustability, for the equivalent of $225 today. It only went up from there.

Pace, for example, has never been cheap, but it’s ubiquitous in military and aerospace (Pace was founded by a military veteran, after all). They’ve been around for over 60 years, and many of their systems cost thousands.

The point is, companies back then weren’t using no-name Chinese crap, they were using name-brand equipment that wasn’t cheap.

I also think you’re ascribing to lead-free all of the increased demands in modern soldering, when in fact the work itself has also changed. 40 years ago we didn’t have nearly as many multilayer boards, with their heat-sucking internal layers. We do a lot more SMD, and we do power SMD packages that didn’t even exist then.

Have you lost the plot? I didn't refer to any cheap Chinese tools. I referred to Hakko and Weller. The expensive Wellers just did what the Curie point ones did, but with a knob to set the temperature. The expensive Hakkos were similar. I used to be a mass murderer, but I never saw a Pace iron in the defence industry. Maybe they were just in the US until recently. Everything I've seen built in the defence industry has been built with a Weller Curie point iron. We assembled 8, 16 and 22 layer boards 40 years ago with those irons, through hole and SMD. The only ones that gave any trouble with lead solder were where someone had messed up the thermal lands. Those had to be fixed whether you used the existing irons, or something that could push out more heat, for reliability reasons.

Metcal was very niche before lead free solder become the norm. Ungar I am only aware of for cheap and nasty products. Ersa has never seemed special. I had never heard of American Beauty before your post.

Note that the need for highly response irons was so small before lead free solder that the RF heated iron was developed and patented by Hakko well before Metcal, but not brought to market until recently, because they couldn't find a market for it.

Hey, relax before you have yourself an aneurysm!

Well you mentioned Weller and Hakko, but then also seem to think that modern equipment is somehow way more expensive, ignoring that that stuff used to be expensive, too!

So… thermally regulated soldering irons regulate temperature. Got it. 

Pace is ubiquitous (≠ exclusive) in military and aerospace. Certainly in USA, but my old boss worked for years in defense and aerospace here in Switzerland and said that Pace is ubiquitous in military and aerospace here, too.

When did Hakko introduce their RF iron? Metcal’s patent was filed in 1986: https://patents.google.com/patent/US4839501A/en

Anyhow, I cannot reiterate enough: I am not saying now, and was not saying before, that lead-free does not demand more of a soldering station, all else held equal.

But I also vehemently disagree with the claim that there is such a thing as a “lead-free” soldering station. It was every bit as possible to find appropriate equipment and processes before newfangled cartridge-heater irons and the like came out. If your equipment and process is slowing you down, it’s not suited to the task — and that’s every bit as true with leaded solder as with lead-free. THAT is my key point.

You started barking at me about employers not buying (supposedly) expensive gear until lead-free, but you never truly answered my question as to HOW lead-free is supposedly slowing things down. You say it takes longer to heat, but that’s simply not true as a blanket statement; match thermal mass and heat flow and you can heat anything as quickly as you want.

[peter-h]

AIUI it has never been demonstrated that metals from electronics, dumped in a landfill, reaches the food chain, in rich countries or in poor countries.

Most lead entering the environment has for very many years been coming from lead used in bulk e.g. car batteries, building materials, etc.

Unless forced by customers (which is generally the case today, so actually any manufacturer has no choice about it) I would not use lead-free because there is no advantage whatever. It needs a higher temperature, and unless you pay a lot of money for some high performance flux (Almit) it doesn't flow as well.

For SMT, the process is "easier" and with modern machinery the commonly used SAC305, with whatever flux is used (I never looked into it) works well enough. The joints are not shiny like with leaded but they are ok.

The thing you still need to watch is components which were not designed for this higher temperature; we are talking about SMT electrolytics in particular and if you get some old stock of these, you can get trouble. Many years ago I had a batch of boards assembled with some Nichicon caps and most of them came back with the tops domed, from gas buildup. It was some old stock of these caps. I doubt anyone will come across this issue today unless they are habitually buying up surplus stocks.

I don't see soldering irons being at all relevant. Pace are good irons, sure. I have them at work and at home.

[coppice]

Most lead entering the environment has for very many years been coming from lead used in bulk e.g. car batteries, building materials, etc.

Lead and copper are in an interesting sweet spot. They are not so expensive that we can't use them for applications that need considerable amounts, but they are so expensive we don't waste them. That means they are recycled to an extent we see with very few other materials. Some lead from buildings may get into land fills, although most large chunks - pipes, roofing, etc. - probably get pick up in the waste management chain recycled. However, car batteries have a pretty well established bi-directional supply chain. I doubt there is much lead that gets into landfills from them. Other smaller and less valuable kinds of lead acid battery, such as motorbike batteries, are probably going into landfills in much larger amounts.

[Jwillis]

A lot of general focus and fear of lead. Over exposure of any metals can cause different health problems. Aluminum have been kinked to Alzheimer's. Copper can cause severe liver damage. Even gold toxicity effects the kidneys and platelet function. Each type of metal having varying health risks at different degrees of toxicity. Handling of most common metals doesn't pose any risk. Toxicity is normally caused by direct ingestion.
The biggest problem with lead is the cumulative effects over long term exposure through direct ingestion. Since lead deposits in the liver and kidneys and stays there. Much the same way as mercury. By reducing the amount of exposure the cumulative effects are also reduced. Lead pipes are a problem because of the amount of lead exposure is very high as compared to the small amount of solder used in copper plumbing.This has to due with the total area of lead salts that slough off as the water passes through the pipe. This relationship of lead plumbing and toxicity was first documented in  around 130 BC.
But we're talking about a lot of lead exposure ingested over a life time and not just a short term handling when using a bit of leaded solder. Wash you hands after use before eating . Don't solder at to high a temperature that can cause the lead to gas off. That bit off smoke produced is the flux contains no lead. Lead needs to reach 900°F/ 482⁰C to become a gas.
Using lead free solder comes with it's own benefits and deficits and is a matter of personal choice for the basic hobbyist. For example I like to use a Indium solder for those plastic package SMD LEDs because of it's very low wetting temperature.Leaded solder for general purpose. Lead free for the high temp applications.
But with anything, proper safe handling and usage procedures is important for your health and environment. But keep in mind that being over neurotic isn't healthy either.