I have a reel of lead/tin solder and for audio use, particularly cables as I prefer it.
Seen waaay too many audio cables and multicores with solder joints not worth the name. Some repairs have to be silver but seeing a lot of v shoddy wave and soldered joints where the Pb free joint is just not good enough.
Good points and recommendations on here for modern acceptable solders. Should really get some good lead free solder for Pro use as if forming company may fall foul of law if carry on using lead solder. will reread and go shopping.
Seen waaay too many audio cables and multicores with solder joints not worth the name. Some repairs have to be silver but seeing a lot of v shoddy wave and soldered joints where the Pb free joint is just not good enough.
Good points and recommendations on here for modern acceptable solders. Should really get some good lead free solder for Pro use as if forming company may fall foul of law if carry on using lead solder. will reread and go shopping.
don't look for 60/40. It goes pasty at setting temperature because it is not a eutectic.
look for 63/37, it is a eutectic and gives better results because it avoids the pasty phase during cooling.
look for 63/37, it is a eutectic and gives better results because it avoids the pasty phase during cooling.
The reason some areas have exemptions from RoHS is not beacause they use older components, but because of reliability and a fear of tin whiskers. In fact most millitary assembly actually use RoHS components, leading to production problems and in the case of BGA's having them re-balled. If you wanna investigate further the IPC is currently working with the DoD to try and resolve a lot of the issues that defence contracters (and medical) have in sourcing components etc. look for:IPC PRINTED BOARD
DEFENSE ROADMAP.
Considering the problems banning lead from electronics has had, it was not a very well thought out idea, least of which is the increase in greenhouse gases created due to the elevated soldering temperature.
Using leaded solder with some new RoHS finishes on components can cause problems, but mainly on SMD lines, hand soldering shouldn't be an issue though.
Personaly I use a eutetic 63/37 and a 3% silver tin/lead, all multicore.
DEFENSE ROADMAP.
Considering the problems banning lead from electronics has had, it was not a very well thought out idea, least of which is the increase in greenhouse gases created due to the elevated soldering temperature.
Using leaded solder with some new RoHS finishes on components can cause problems, but mainly on SMD lines, hand soldering shouldn't be an issue though.
Personaly I use a eutetic 63/37 and a 3% silver tin/lead, all multicore.
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Some people like to get all worked up about the toxicity of lead and insist that everyone should use lead free solder. Well there are other things in this world that are toxic other than lead. In particular, the exotic fluxes needed to make a good joint with lead free solders can be especially toxic.
In the lab at work here (telecoms firm), the lead soldering stations are as simple as a desk with a solder iron (or two, or ten). There is usually a simple fume extractor - basically a ~100 mm fan (like a computer case fan) with a charcoal filter on it. People rarely use them.
Now, the lead-free soldering station... that is something else. The fume extractor for that thing is the size of a microwave oven. It has this fancy bendy hose with a nozzle that you need to place within centimeters of the work area to extract all the fumes. There are big warning signs stating that you are required to use the extractor, as well as eye protection. That setup kind of scared me away from using lead-free at home. I can't afford the safety equipment.
In the lab at work here (telecoms firm), the lead soldering stations are as simple as a desk with a solder iron (or two, or ten). There is usually a simple fume extractor - basically a ~100 mm fan (like a computer case fan) with a charcoal filter on it. People rarely use them.
Now, the lead-free soldering station... that is something else. The fume extractor for that thing is the size of a microwave oven. It has this fancy bendy hose with a nozzle that you need to place within centimeters of the work area to extract all the fumes. There are big warning signs stating that you are required to use the extractor, as well as eye protection. That setup kind of scared me away from using lead-free at home. I can't afford the safety equipment.
Macboy, excellent and often forgotten point, FLUX FUMES. Eating lead is safer than sniffing flux fumes, as my ashmatic lungs will testify too, I started in electronics B4 compulsary extraction, quite agressive fluxes etc, where as being brought up in a house with lead water pipes any done yet hasn't me harm.
FYI
why lead free is not used for critical applications.
EMS007 Lead-Free in Mission Critical: Failure Is Not An Option
why lead free is not used for critical applications.
EMS007 Lead-Free in Mission Critical: Failure Is Not An Option
The main reasons for exemptions at the moment when ROHS rules were laid out were reliability and lack of ROHS compliant components for certain usage scenarios. Typically one doesn't use brand new components for critical applications. You want to be 120% certain the freaking thing works and more important: to be able to predict when and how it will fail in the field. Gathering that kind of data typically takes a few years extra. So manufacturers got that extra years, but right away wasted many of them by not switching to ROHS compliant production when they could, but only when the rules required them to do so.
What I find ironic is the trouble we all went through to remove lead from electronics that goes to landfills, while instead we also could have worked out a way to recycle all of the mess, something we likely have to do anyway in the long run. I wouldn't be surprised that if we start recycling the electronics we'll find out lead-based items are easier and cheaper to recycle.
All in all we're going way off topic, this is not about lead or lead-free but about what the numbers mean and what the OP should use. Like I stated, for DIY it's fine to use a lead based solder if you have it lying around. Just make sure it's a type for soldering electronics. But if you do select a modern lead-free type, there's no need to worry about many things mentioned here:
- The modern lead-free solders have a much lower melting point, it's not that much higher than a "classic" solder. Component damage as a result from the higher working temperature is much less likely than it was some years ago. Despite that I do urge people to work fast, to not let the components heat up too much.
- In many types the flux isn't corrosive anymore, so no damage to the PCB in the long run. I still clean the PCB, but that's because I want it to look neat.
- It's much easier to use lead-free than it was years ago. In many ways it is working just as easy as a lead-based solder.
And as the OP isn't going to work with it for over 40 years day-in day-out, it's safe to say a well ventilated workspace (IMO always a must for any soldering) should be good enough for the few joints the OP has to make.
Got to disagree with your first paragraph, sorry, but new componets are used in critical applications, if they are BGA's they are re-balled. A lot of critical and military design is cutting edge and requires the use of the most up to date components, expensive multilayer and flex-rigid PCB's. And for some realy critical designs embedded passives, all cutting edge technology.
rohs has to be seen in conjunction with wee. Dumping electronics into landfills was out of discussion long before banning harmful substances. However legislation really took some time.
regards
Some basic thoughts:
Single sided and double sided PCB’s – non plated holes:
Land and Hole Sizes: Hole sizes should be carefully chosen to give the maximum amount of mechanical support for the component lead, while not impeding lead insertion. This is to limit the amount of stress put on the solder joint and the hole pad, thus limiting defects and possible failure mechanisms. The land size should be large enough to allow a good solder fillet and provide sufficient area for pad to PCB bond, as this is the primary bond for these pads (no plated through hole acting as a rivet), If solder resist is being used these pads can be made over size and the solder resist mask used to define the soldering area, this again increases the pad to substrate bond (this technique is also used for Flexi PCB’s).
Leaded solders are better for these kind of joints as they are more malleable than Pb free solders, ales prone to dry joints and cracking.
For square leads the hole can be slightly smaller than the diameter of a circle that would circumscribe the leads cross section, the corners of the lead will cut into the circle giving a lot of mechanical support. For rounded leads again the tighter the fit the better, remembering that round leads will require a whole greater than their diameter as they can not be forced into w whole like square leads.
The strength of these joints is made up of the solder fillet, the pad to substrate bond and any addition mechanical support the hole provides, as such they are the most prone to failures due to; vibration, thermal cycling, mechanical stress etc, where possible I would recommend PTH (plated through holes) where costs allow.
Single, double sided and multilayer PCB’s –Plated Through Holes:
The joints integrity does not only consist of the solder fillet and pad, but also the solder in the barrel of the hole formed by the through plating, which contributes approx 75% of the strength of these kind of joints. Due to the barrel being present, the land diameter for plated through holes can me smaller than non plated holes as the plated barrel ‘rivets’ the pads to the board. The hole size again depends on the lead diameter (or circumscribed diameter for square and rectangular cross section leads), but also the type of solder used (SnPb or Pb free) and the soldering process. As we are mainly dealing with hand soldered joints an increase of 0.2mm (8 thou) over the lead diameter should suffice for most situations (and is in fact the standard figure used within electronics design and production and IPC standards).
The aim with plated through holes is to achieve a joint where you have a nice fillet between the pad and the lead, but also more importantly the solder flows up at least 75% of the barrel and preferably all the way through to form a flat fillet at the top of the hole.
Tin lead solder flows better than lead free so it is easier to achieve the required joint, again though with hand soldering you have more control over each individual joint, so getting the desired results can be achieved with either solder.
I have only covered initial basics of soldering, and only through hole components. Surface mount design and assembly brings even more variables into the equation, which could be discussed if people want (surface finish, reflow profiles etc etc.)
I have included a few links for further reading and further research if required. If people want to get further into soldering and PCB design a good starting point would be getting hold of the following IPC specs as a good industry based standard:
IPC – 2222 series
IPC-6011/12
IPC-A-610
Printed Circuit Design and Fabrication:
Printed Circuit Design & Fab Magazine Online
Soldering Defect Data Base and Joint evaluation:
http://www.ipctraining.org/demos/pdf/drm-pth-d.pdf
National Physical Laboratory Industry Defects Database
Soldering Basics and Gudes to soldering:
EPE "Basic Soldering Guide"
Electronics 2000 | Beginners Guide | Soldering
7.1.1 Soldering Basics
Lead and Lead Free:
http://www.dklmetals.co.uk/PDF Files/Factorfiction.pdf
http://www3.uic.com/wcms/Images.nsf/(GraphicLib)/IPCNewOrleans.pdf/$file/IPCNewOrleans.pdf
😀
Single sided and double sided PCB’s – non plated holes:
Land and Hole Sizes: Hole sizes should be carefully chosen to give the maximum amount of mechanical support for the component lead, while not impeding lead insertion. This is to limit the amount of stress put on the solder joint and the hole pad, thus limiting defects and possible failure mechanisms. The land size should be large enough to allow a good solder fillet and provide sufficient area for pad to PCB bond, as this is the primary bond for these pads (no plated through hole acting as a rivet), If solder resist is being used these pads can be made over size and the solder resist mask used to define the soldering area, this again increases the pad to substrate bond (this technique is also used for Flexi PCB’s).
Leaded solders are better for these kind of joints as they are more malleable than Pb free solders, ales prone to dry joints and cracking.
For square leads the hole can be slightly smaller than the diameter of a circle that would circumscribe the leads cross section, the corners of the lead will cut into the circle giving a lot of mechanical support. For rounded leads again the tighter the fit the better, remembering that round leads will require a whole greater than their diameter as they can not be forced into w whole like square leads.
The strength of these joints is made up of the solder fillet, the pad to substrate bond and any addition mechanical support the hole provides, as such they are the most prone to failures due to; vibration, thermal cycling, mechanical stress etc, where possible I would recommend PTH (plated through holes) where costs allow.
Single, double sided and multilayer PCB’s –Plated Through Holes:
The joints integrity does not only consist of the solder fillet and pad, but also the solder in the barrel of the hole formed by the through plating, which contributes approx 75% of the strength of these kind of joints. Due to the barrel being present, the land diameter for plated through holes can me smaller than non plated holes as the plated barrel ‘rivets’ the pads to the board. The hole size again depends on the lead diameter (or circumscribed diameter for square and rectangular cross section leads), but also the type of solder used (SnPb or Pb free) and the soldering process. As we are mainly dealing with hand soldered joints an increase of 0.2mm (8 thou) over the lead diameter should suffice for most situations (and is in fact the standard figure used within electronics design and production and IPC standards).
The aim with plated through holes is to achieve a joint where you have a nice fillet between the pad and the lead, but also more importantly the solder flows up at least 75% of the barrel and preferably all the way through to form a flat fillet at the top of the hole.
Tin lead solder flows better than lead free so it is easier to achieve the required joint, again though with hand soldering you have more control over each individual joint, so getting the desired results can be achieved with either solder.
I have only covered initial basics of soldering, and only through hole components. Surface mount design and assembly brings even more variables into the equation, which could be discussed if people want (surface finish, reflow profiles etc etc.)
I have included a few links for further reading and further research if required. If people want to get further into soldering and PCB design a good starting point would be getting hold of the following IPC specs as a good industry based standard:
IPC – 2222 series
IPC-6011/12
IPC-A-610
Printed Circuit Design and Fabrication:
Printed Circuit Design & Fab Magazine Online
Soldering Defect Data Base and Joint evaluation:
http://www.ipctraining.org/demos/pdf/drm-pth-d.pdf
National Physical Laboratory Industry Defects Database
Soldering Basics and Gudes to soldering:
EPE "Basic Soldering Guide"
Electronics 2000 | Beginners Guide | Soldering
7.1.1 Soldering Basics
Lead and Lead Free:
http://www.dklmetals.co.uk/PDF Files/Factorfiction.pdf
http://www3.uic.com/wcms/Images.nsf/(GraphicLib)/IPCNewOrleans.pdf/$file/IPCNewOrleans.pdf
😀
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