I was planning on getting into electronics as a hobby seriously, and I read that they have or will ban lead solder. Is it already illegal? Is traditional lead/tin/rosin solder still available to buy? Do we really need such a ban? I think I should stock up on the traditional solder if I can because from what I read, lead free solder is terrible, especially since I want to mainly work on repairing old electronic equipment. I'm wondering if it will even be possible to be an electronics hobbyist anymore.
The situation is complex, and it depends on where exactly you are located. As far as Europe goes, leaded solder is NOT illegal, and is unlikely to become so. Supplies are still fairly readily available, although not as abundantly as they were, as obviously, there is less demand. The directives regarding the use of lead-free solder, allow for amateur and non-commercial use of leaded solder, basically without restriction. Any equipment which was "placed on the market" prior to July 1 2006, can be repaired, commercially, using leaded solder if you wish. If it was constructed originally using leaded solder, then the general opinion is that it should be repaired using leaded solder, as there is considerable controversy as to whether leaded and lead-free solder alloys mix to produce a joint with long-term stability.
If the item was originally constructed using lead-free, then for the same reason, use lead-free to repair it. Any item that was placed on the market after July 1 2006, will definitely be constructed using lead-free solder, and lead-free components ( the other angle to staying within the terms of the directive ). If you are a commercial repairer, you MUST use lead-free solder and direct replacement or compatible lead-free RoHS ( Restriction of Hazardous Substances ) certified components to perform any repair on this equipment, and not commit a theoretical criminal offence. I say theoretical because to date, I am not aware of anyone being prosecuted, or any means being in place to police the directive.
You are not required to follow the terms of the directive for this equipment, if you are working on it non-commercially ie for your own personal purposes. Most commercial equipment has been manufactured in lead-free for more than 2 years now, and some manufacturers - Sony for instance - have been insisting for some time that their dealers use only lead-free solder for carrying out repairs to their equipment, irrespective of age or original construction materials, so apparently, they don't believe that there is an issue with mixing alloys.
There is a lot of information on the web about this if you search " RoHS " directive. Also, there is a lot of valuable information on the major component suppliers' websites such as Farnell and RS Components. If you can get hold of a copy of " Technology @ Home " magazine ( last issue ) -
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you can find the more comprehensive article that I did.
You *need* tin lead solder for repairing old gear and it's still widely available for that very reason. It's also hugely nicer to use.
There are a number of categories of equipment that are still allowed to use tin lead solder too. The lead free thing is intended mainly I think to apply in reality to consumer goods but the legislation in the EU doesn't distinguish as such.
Mixing leaded and lead-free solders can be problematic. Generally if a device was built using leaded solder then leaded solder should be used for repair. For lead free assemblies, of course lead free solder should be used. The big question is, how will you be able to tell whether or not a board was put together using leaded or lead-free solder? Hopefully some mfrs will mark their boards accordingly but I doubt if many will. Just because some components may be marked as being 'lead free' or 'RoHS compliant' doesn't mean the board was assembled with lead free solder. Lead free parts will work fine with leaded solders as well as lead free solders.
As far as hobby work goes there's nothing wrong with using lead free solder for hand work. It's slightly more difficult to work with, but high silver bearing solders such as SAC305 formulas seem to work the best. Using lots of flux is important as well, since a more agressive flux is needed than with tin/lead solder to ensure proper wetting. But if you are a soldering newbie it might be better to start out with some tin/lead solder until you get the hang of it as it is a little more forgiving...
Are there manufacturers that are not marking their boards for lead content? I thought it was required in Europe and all of the CE vendors that I have seen in the US are marking the boards.
What is the problem with mixing the solders? Other than the lead free types making it harder to rework and needing slightly higher temps, what problems are there? What does "problematic" mean in this case? Is there a real issue or does it mean that you are not sure and are being conservative?
Leonard
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I have done quite a bit of research into this, and have corresponded with several experts in the field, and it seems that the jury is still out on this one. Half of the solder manufacturers say that it's ok to mix leaded and unleaded, and half say not. Some of the experts that I have spoken to say definitely not, so make up your own mind. I prefer not to mix them, as it seems that marginally more people seem to be saying don't than do. As the solder is still available, I see no reason to risk an unknown long term compromise in the stability of the joint, and will continue to use like for like, unless forced by product availability, or legislation, to do otherwise.
Personally, I think that the whole thing is an ill-conceived and poorly thought through excuse to justify the existence of an EU department, and the jobs of those who work in it. And, as I've said before, the avionics industry, and medical instruments industry, amongst others, have been granted an exemption, and the American military flatly refuse to use it, so what are we to make of that ... ?
From what I've read about the subject, it comes down to metallurgical issues. If a part with tin/lead plated leads is used in a lead free process, the lead will contaminate the joint. As little as 0.5% lead is enough to weaken the joint and lead to cracking around the footprint. What happens is the lead, as it melts at a lower temperature than tin (we're not talking about alloys here but trace contaminating amounts), will collect in the joint at the place that cools last, which is the center of mass, right under the footprint. (Obviously we're talking about SMT components here). This reduces the amount of tin doing the actual bonding of the lead and can lead to early joint failure.
Boards made with lead free solders have been found to have better reliability when thermally cycled, one reason the automotive companies have embraced lead free assembly here in the USA. Long term reliability due to tin whiskers is the issue no one wants to talk about however, as the process of whisker formation is still not well understood.
I usually do, adding some fresh solder to help it off.
Leonard
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Do you leave a tiny bit of saturated braid on the end when you trim it? It helps conduct the heat to the joint faster and minimizes heat damage. I try to leave about half the width of the tip when I trim solder wick, then dip it about 1/4 inch into fresh liquid RMA flux. I've changed thousands of ICs this way with almost no damage to the PC boards.
The few that were damaged were mostly due to other causes, like some idiot slamming a fist down on the bench while you're working because they think you're ignoring them, or defective PC boards that have all kinds of loose foils and pads. I have to see if my digital camera will do decent macro shots. If it does, I'll put some pictures for the new people on my website. BTW, How's business?
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One problem occurs if you use leaded solder on surface-mounted components. Lead amalgamates with the silver that is "fired" onto these components, ruining their electrical connection.
I've read that a lead-contaminated solder iron can cause the problem even if lead-free solder is used. I've never heard of the opposite case with lead-free solder.
The metalurgical wisdom is that leaded and lead-free solders should not be mixed in the same joint, as the mixing can, apparently, compromise the long-term integrity of the joint. I don't know whereabouts in the world you are, but across Europe, strictly speaking, it is actually illegal to use leaded solder, or non RoHS components, to repair anything manufactured in lead-free after implementation of the RoHS directive, which was June 2006 (I think) in the UK. Prior to that time, some manufacturers, notably Sony, were already manufacturing in lead-free, and insisting that their dealers used
*only* lead-free to effect repairs to all of their equipment, irrespective of whether it was originally manufactured in lead-free or leaded solder. This actually flew in the face of expert advice which recommended using only the type of solder that the equipment was originally manufactured with. There was no legal mandate to use lead-free solder for repairs to any equipment manufactured prior to RoHS implementation, whether it was manufactured with lead-free, or not. There is still no legal requirement to use lead-free solder to repair any equipment originally built with leaded solder.
As to whether lead-free damages tips, that's a bit of a grey one. If you are using iron-clad tips, then yes, it does rot them much quicker than leaded solder does. The reasons for this appear to be threefold. According to Cooper Tools, who manufacture Weller soldering equipment, the composition of lead-free solder has a tendency to 'leach' iron from the tip coating, resulting in it failing quite quickly, and exposing the underlying copper, which then rapidly burns away. Secondly, because lead-free solder does not wet joints as well as leaded solder did, much more aggressive fluxes have to be used, and again, these have a detrimental corrosive effect on the iron tip coating. Thirdly, the temperatures required for lead-free hand soldering are typically 30 deg C higher than those required by leaded solder. These higher tip temperatures tend to exacerbate tip degradation. My experience with Weller iron clad tips, would tend to bear out the contention that lead-free solder destroys them much quicker than leaded did.
That said, a few months back, Antex changed their tips back to being what looks like chrome plated, as they used to be 30 years back. This seems to have produced a significant improvement in the life of their tips, and I wonder if they have done it to combat the negative effects on tip life that lead-free has given us.
As to mixing leaded and lead-free on the same tip, unless you are going to keep completely separate irons burning all the time, I think that it's pretty much unavoidable in a typical workshop environment, dealing with many types and ages of equipment. If you keep a wet sponge on your iron's stand, and get into the habit of giving the tip a wipe every time you pick the iron up, then I don't think that any residual quantities of either type left on the tip, will be enough to cause any problems.
Luckily, here in the US you can buy and use any type of solder ever made. The issue which I've avoided but can't be ignored is that there's lots of that RoHS crap floating around and I will at some point have to deal with it.
A friend that's starting out in electronics and building some basic kits wants to use a soldering iron.
I'm not clear on if I should just grab a spare and hand them a roll of
60/40, or get new tips for them and let them start "fresh" with some lead-free sample packs from trade shows. It's all through the hole stuff, and probably doesn't matter at al for what they're doing now.
Also are there any foolproof method of telling if lower production type items are traditional or lead-free?
If the friend is not already an experienced hand-solderer, and there is no legal requirement for him to use lead-free, then I would not start him off with it. Even the latest alloys specifically for hand soldering, still have a bit of a 'pasty' feel to them, and are not intuitive to solder with, as leaded solder was. Even for the most experienced of us, lead-free solder is still quite easy to make bad (or mechanically not very good) joints with, particularly on large components, and those which are reluctant to take solder in the first place.
If your friend is doing kit building just for himself, then maybe you could consider introducing lead-free at some point in his training, once he has got the hang of leaded soldering, but if there is any commercial angle to his activities, where any lack of reliability will come down on his head, then I would say stick to leaded if your local laws allow. Of course, if there is a commercial angle, and he has any intention of selling internationally, then he must consider that it may be a requirement that he uses lead-free.
There doesn't seem to be a reliable way of telling lead-free for definite, without some 'help' from the manufacturers. This help is usually in the form of a symbol silkscreened on the board that is either a circle with the letters Pb in it, and a strike-through line across it, or the letters "PbF". In general, if a commercially sold piece of consumer electronics has been built in either Europe or the far east since mid 2006, it will definitely be lead-free. I believe Australia is the same, but I'm not sure of the date they went lead-free. Perhaps one of the Oz lads in the group can help out with that one. Mr N.Cook on here has done considerable research on trying to come up with a definitive test for lead-free. If you search this group for the last 6 months of posts by him, you should catch them all. Other than this, with a good eye, you can identify most lead-free constructed boards. The joints tend to have a dull grey surface, and are shaped more like a volcano than the typical leaded joint which has a concave profile between the pad and component leg. If you apply a normal non temperature controlled iron to a lead-free joint, you will quickly spot the difference. It just doesn't melt, flow and resolidify in the same eutectic way as leaded solder - particularly at leaded solder temperatures.
Unless you have an in with the manufacturer, or you exclusively repair top-tier industrial hardware that is very well documented, you have no idea what kind of solder was originally used. Yes, it may have a green checkmark on it, and yes, you may be very competent at identifying lead-free solder by the look and feel, but there is a wide variety of lead and lead-free solders out there, and mixing two lead-free alloys can make a connection that's as unreliable as a mixed lead/lead-free joint. Essentially you are randomly mixing metals with no controls. You also don't know if the engineers chose to use non-lead-free components on a lead-free board, or tweaked the profile to compensate for the "right" solder being unavailable. If you're fixing something made in China, you can't claim to know anything at all about it. That board could have been assembled with melted-down jewelry from Wal- Mart. So much goes on behind the scene that you'll always be guessing.
I have never heard of lead and silver causing trouble. I've been using RS 2% Ag "hi tech" solder since the 80s for no particular reason other than the old tektronix scopes I worked on back then had silver-ceramic barrier strips in them; you had to use solder with silver or it would strip the metal from the ceramic. The stuff works just as well on motherboard bridges today.
Another thought on mixing lead and lead-free: While it may cause unreliability issues, you'll never have a warranty claim as a result. We're talking decades here, not months. How long is that piece of equipment going to be in use?
This is not new. Tektronix used to include a bit of silver bearing solder with their scopes so you wouldn't ruin the plated ceramic terminal strips if you changed out parts.
Jeff
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