Hi,

This is possibly a stupid question so please forgive me.

If you have a pcb with lead-free tinned pads, do you have to use lead-free solder or is leaded fine?

What would be the consequences of doing this?

 

The consequences are you get rapped on the knuckles and thrown into the clink by the RoHS police.

 

You can use leaded as long as you are not required to use lead free or required to be in compliance with ROHS ..
Typically that only applies to companies and not individuals..

But it may be a law in your country that does not specify company or individual..
Now that you have put this question into the public domain they are coming for you to bust your knuckles as stated by MrChips

 

If you have a choice, lead solder is preferred, since it's generally easier to solder with.

 

Thanks guys, this is not required to be in compliant with ROHS.

 

RoHS (Reduction of Human Satisfaction)

 

If you have a pcb with lead-free tinned pads, do you have to use lead-free solder or is leaded fine?

What would be the consequences of doing this?

It depends on your local regulations. Solder with lead is banned in the EU, but my impression is that hobbyists were exempted from the restriction.

 

RoHS (Reduction of Human Satisfaction)

The consequences are you get rapped on the knuckles and thrown into the clink by the RoHS police.

While yes, leaded solder is usually easier to work with, you should try to avoid it given the chance. The thing with lead is that it can build up over time in you, and in the environment and food, and then it just stays there. It can be very detrimental to your health, and your health (and that of others) is more important than avoiding an inconvenience. RoHS is especially important for consumer electronics, or where others may not be aware of the lead/poison content. And it is completely unnecessary to use lead in many things that it is used in. Companies are often just trying to be cheap. So, please. Go with the RoHS solder, and try to use RoHS components.

 

While yes, leaded solder is usually easier to work with, you should try to avoid it given the chance. The thing with lead is that it can build up over time in you, and in the environment and food, and then it just stays there. It can be very detrimental to your health, and your health (and that of others) is more important than avoiding an inconvenience. RoHS is especially important for consumer electronics, or where others may not be aware of the lead/poison content. And it is completely unnecessary to use lead in many things that it is used in. Companies are often just trying to be cheap. So, please. Go with the RoHS solder, and try to use RoHS components.

By and far the major risk of lead is to young children, and those effects can be permanent. The physiologic reasons for that are well documented.

For adults, metallic lead is relatively harmless. In fact, lead bullets embedded in soft tissue do not cause any measurable increase in blood levels. That is, "died of lead poisoning" when referring to being shot is an comic exaggeration. Only if the bullet is lodged near a bone is there any measurable effect on lead levels. Lead is excreted from adults with a half-life of about 1 month (https://emedicine.medscape.com/article/2060369-overview). That is, in 6 months, only 1.6% of an acute dose of lead in an adult's blood is still there. We all have lead in our blood from environmental exposure.

 

Just remember to wash your hands before eating. Lead free solder is pretty horrible to work with. Some of my boards have to be lead free. I find surface mount soldering by hand is a lot harder with lead free.
Paste flux is your friend!!

 

While yes, leaded solder is usually easier to work with, you should try to avoid it given the chance. The thing with lead is that it can build up over time in you, and in the environment and food, and then it just stays there. It can be very detrimental to your health, and your health (and that of others) is more important than avoiding an inconvenience. RoHS is especially important for consumer electronics, or where others may not be aware of the lead/poison content. And it is completely unnecessary to use lead in many things that it is used in. Companies are often just trying to be cheap. So, please. Go with the RoHS solder, and try to use RoHS components.

BS the amount of lead to which the average hobbyist is negligible. Take proper precautions like washing hands after use and keeping the solder away from children and you will be fine. The smoke from solder flux is more dangerous than any lead you might be exposed.

 

It can accumulate over time. It is not that a little bit of left over lead will kill you, but rather that it can accumulate. And it it not just very young children at risk. While you might be able to get rid of most of it if exposed to it once, some will certainly stay in you, and it can certainly have detrimental effects. In addition, you can have adverse neurological effects without them being too noticeable or huge.

 

It can accumulate over time. It is not that a little bit of left over lead will kill you, but rather that it can accumulate. And it it not just very young children at risk. While you might be able to get rid of most of it if exposed to it once, some will certainly stay in you, and it can certainly have detrimental effects. In addition, you can have adverse neurological effects without them being too noticeable or huge.

Yes! I have always stressed to my PCB assemblers, work experience people and students to be very careful about washing well after soldering. It is a bit silly not to take such a simple precaution anyway.
And the fumes are bad too. I blame my many years of breathing solder smoke for my lung disease. It may not be so, but I reckon it did contribute.

 

It can accumulate over time. It is not that a little bit of left over lead will kill you, but rather that it can accumulate. And it it not just very young children at risk. While you might be able to get rid of most of it if exposed to it once, some will certainly stay in you, and it can certainly have detrimental effects. In addition, you can have adverse neurological effects without them being too noticeable or huge.

The hobbyist isn't soldering every single day. The act of soldering is only a small part of the hobby.

Hobbyists have been using lead solder for a couple of generations now. With all that usage there should be amble medical evidence to support your claim that lead solder is a danger to hobbyists. Provide some. It should be easy to find medical proof considering the number of hobbyists that use leaded solder.

 

The only occupational lead exposure cases I've heard of in the electronics industry involved third world sweat shop solderers holding the solder in their mouths and smoking while never washing their hands. Even then, their bigger problem was taking lead residue home to their children.

For most of us, the risks from lead in solder, taking reasonable precautions, are negligible while the harm from breathing the fumes from the strong fluxes used with lead free solder are very significant.

The battery recycling, mining and shooting range industries are the only ones I'm aware of where more diligence is warranted.

 

The battery recycling, mining and shooting range industries are the only ones I'm aware of where more diligence is warranted.

Most shooters are probably exposed to lead far more frequently than someone with an electronics hobby.

And that isn't counting the shooters that reload. Their exposure would be comparatively significant yet I have never heard of a case where a person that loads has suffered from lead poisoning.

 

Until lead was removed from gasoline other precautions against lead, with the exceptions lead paint and lead pipes for potable water, were largely farcical. The transition from tin-lead solder to lead-free solder came at a time when the total amount of solder used in an electronic product dropped dramatically due to the change to surface mount. But then Jobs turned computers into bling and the rate of e-scrap generation skyrocketed.

There is no doubt that lead is a serious cumulative toxicant and you'd have to be a compete fool not to follow basic precautions like hand washing. There was a time that the dangers of many things (see phossy jaw, if you aren't squeamish) were not understood, but for the most part those days are long long past. Sadly there is still gross failure on the part of many businesses to assure their employees know the risks and observe the precautions.

 

Generally, people confirm things are NOT poisonous before exposing themselves to them, as opposed to continuing to expose themselves to it until there is completely undeniable evidence that it's poisonous. And companies selling poisonous products just need there to be some sort of controversy so that because of the confirmation bias, people still buy/use poison. Take, for example, tobacco products. People knew it contained carcinogens for a really long time, but until they could completely prove it caused lung cancer, most people decided to ignore the growing evidence. There was controversy, so they could chose to continue smoking. While it is not the same as smoking, you should certainly still be careful.

 

Most shooters are probably exposed to lead far more frequently than someone with an electronics hobby.

And that isn't counting the shooters that reload. Their exposure would be comparatively significant yet I have never heard of a case where a person that loads has suffered from lead poisoning.

Somewhat non-intuitively, the biggest exposure most shooters experience, in a form that can be harmful, is the plume of lead compounds coming out of the gun from the lead styphnate or lead azide in the cartridge primer, not from the lead contained in the bullet.

The people who've had serious exposures have all been instructors, competition shooters, range maintainers, etc; those with frequent and/or lengthy contact.

 

I just think that regardless of how badly it will affect you, you should still try to avoid it. You may not know until it's too late. In my opinion, no poison is better than a little poison. I know that there is also some in the environment, etc, but there is no reason not to try to limit your exposure.