Guest lightnix Posted March 23, 2009 Share Posted March 23, 2009 I had this mad idea recently, to build a small analogue synth kit; but retained enough sanity to realise, that I need to brush up on my soldering / PCB skills first and so decided to get a bit of practice in with a some simple fun stuff, starting with this little chap :D Then I read a warning on another kit site (I forget which), saying that they wouldn't guarantee any kits made with lead free solder. Curiosity aroused, I had a :D and read all sorts of conflicting opinions on the virtues (or lack thereof) of lead free-solder. Many claim that lead-free solder is nothing short of a slow, self-destruct mechanism, guaranteed to render even the most carefully-constructed boards useless in less than a decade; as whiskers of tin crystallise out of the solder and eventually short out every single connection. Others claim that whiskers are only a problem in older / inferior lead-free solders. Deciding to err on the side of caution (as opposed to safety), I sallied forth in search of some good, old-fashioned, full fat solder with proper lead in; first to Maplins, then to the local independent electrical shop, both of whom told me that it was "illegal" for them to sell me anything other than lead free solder. Which is odd, because I ordered a nice big roll off RS, no problem :) So what's the truth here? Is lead-free solder as naff as they say, or should I be hauled up before the Euro-Courts by the Enviro-Fuzz, for polluting my environment with toxic heavy metal? :) Link to comment Share on other sites More sharing options...
Blaize110 Posted March 23, 2009 Share Posted March 23, 2009 As far as I know(someone correct me if I'm wrong) that it is illegal for certain companies to sell products with a certain lead contect in. (Probably was always to some exetent but I think the percentages have changed). For this reason many suppliers now dont see it as economically viable or are erring on the side of caution and not selling leaded solder. However the general public and schools (seems rather ridiculous bearing in mind the side effects of lead) are still allowed to buy leaded solder. I usually get mine from ebay because the lead free stuff has a higher melting point and my cheapo iron struggles to melt it. Link to comment Share on other sites More sharing options...
Shez Posted March 23, 2009 Share Posted March 23, 2009 I'm sure CPC still sell it, just marked as 60/40 though.I bought a 500g reel of "proper" solder about 20 years ago which is still going strong and will likely outlast me. I'm certainly not expecting to have to buy any more any time soon! Link to comment Share on other sites More sharing options...
KevinE Posted March 23, 2009 Share Posted March 23, 2009 You can buy proper solder from most places still. Lead-free requires a slightly higher bit temperature, and is deemed not to be compatible with components that have had their legs tinned with conventional solder and vice-versa...for some reason. Some of the cheaper 60/40 cored solder is awful, I had a roll once that ran out of flux core half way through its length..I swapped back to multicore and have been ok since. Link to comment Share on other sites More sharing options...
Ynot Posted March 23, 2009 Share Posted March 23, 2009 Hmm.... I spent the majority of my formative teenage years and most certainly a good decade and a half or more working with good old leaded solder. And it's not done me any harm whatsoever.... Wibble.:) Link to comment Share on other sites More sharing options...
musht Posted March 23, 2009 Share Posted March 23, 2009 It requires a bit more heat, which is fine with gas iron or temp controlled, might be struggle with some older irons. Dosent flow or wet as nicely as full lead stuff. Gold plating on PCB makes life lot easier. Silver loaded lead free is worth the extra. Tin whiskers and fracturing are couple of possible issues. Full lead is available supposedly for repair and re-work on pre RoHS stuff and is probably due to be phased out sometime. It is probably a bit of a time bomb for a lot of electronics. Link to comment Share on other sites More sharing options...
Simon Lewis Posted March 23, 2009 Share Posted March 23, 2009 Some years back, I carried out a small project with a portable pump drawing air samples through a particulate filter which I then analysed using ICP-OES and ICP-MS. The fumes produced during soldering have very little if any lead in them. The hazard from lead solder arises when the circuit board is scrapped and thrown into landfill. Here, acid leachate may dissolve the lead, and leaks in the landfill liner (presuming it has one!) means that potentially, heavy metal rich leachate liquors can make their way into watercourses. The risk to health during soldering is from the rosin fumes. These are particularly unpleasant and are considered to be the prime cause of occupational asthma. The solid and fume can also cause dermatitis. Therefore it is good practice to use some form of fume extraction. This leaflet explains more. I understand that lead based solder is allowed for repair and maintenance of equipment that already has lead based solder. For this purpose, I bought a few rolls to allow this activity to be carried out ;-) Simon Link to comment Share on other sites More sharing options...
martinw Posted March 23, 2009 Share Posted March 23, 2009 The long term reliability of lead-free solder is still something of an unknown, and I think leaded solder is still actively used for safety-critical applications. When lead-free solder first started being used about 5 years ago, there was a lot of mad hand-waving within the electronics industry, amid claims of the sky falling in. One significant problem was that a lot of components couldn't tolerate the higher temperatures required to reflow the solder. Its now pretty well understood. Most electronics assemblers can cope with it with no drama, and the component manufacturers have revised parts which can cope with the heat, although it did take a while to get to this point. Having said that, if I have to do any hand soldering work - I'll always use the leaded solder, as I find it much easier to work with. I'm not sure if the benefit of less lead in landfill sites is outweighed by the extra electricity require to run reflow ovens at a higher temperature. Martin Link to comment Share on other sites More sharing options...
slim_mcslim Posted March 24, 2009 Share Posted March 24, 2009 Nasa have done a lot of work on tin whiskers.... (not the cat food) as it seems to be one of the main causes of failiure in multi million dollar satellites. Link to PDF on research... I was amazed when I first learned about these, its a fascinating and little understood area of science, albeit not that interesting it does go a long way to explaining unexplained random electrical failiure. Back to the lead free solder, all I can say its damned near imposible to make up cheap XLR connectors with the stuff, and DIN plugs turn into a pile of molten plastic before you have even heated the solder to melting point. Amphenol connectors seem to offer the most heat resistance when making up. Link to comment Share on other sites More sharing options...
Stuart91 Posted March 24, 2009 Share Posted March 24, 2009 My understanding is that the medical and aviation industries have been given an exemption from the requirement to use lead-free solder. What does that tell you about the reliability of it? Link to comment Share on other sites More sharing options...
Bobbsy Posted March 24, 2009 Share Posted March 24, 2009 RS in Australia still have plenty of varieties of 60/40 leaded solder--I assume the mother ship in the UK would too. (Says the guy who assumed it would become unavailable so stocked up on a lifetime supply and paid to ship it around the world!) Bob Link to comment Share on other sites More sharing options...
Guest lightnix Posted March 24, 2009 Share Posted March 24, 2009 Thanks for all the replies, guys - most interesting :P Maybe I should stock up on some leaded solder and sit on it until it finally does get disco'd - then flog it by the metre on eBay for ££££££. I mean... with the "interest" (pffft) that I'm getting on my savings right now, I could do with another form of investment B-) Link to comment Share on other sites More sharing options...
Roderick Posted March 24, 2009 Share Posted March 24, 2009 Aside from rosin fumes there is a real risk of lead poisoning. Lead is a poison that slowly builds-up in your body and can have a bad affect on your health because your body can't break it down or get rid of it.When you are soldering, wash your hands before having a snack, or a smoke, to avoid the transfer of lead from your hands to your mouth.If you are the occasional solderer, the risk are pretty minimal but it can be an issue for people who use solder daily. Link to comment Share on other sites More sharing options...
Rob_Beech Posted March 24, 2009 Share Posted March 24, 2009 The irony of washing your hands of lead before smoking a cigarette. Link to comment Share on other sites More sharing options...
lightsource Posted March 26, 2009 Share Posted March 26, 2009 Thanks for all the replies, guys - most interesting :) Maybe I should stock up on some leaded solder and sit on it until it finally does get disco'd Think I'll join that club :D When you are soldering, wash your hands before having a snack, or a smoke, to avoid the transfer of lead from your hands to your mouth. So, healthwise, I'm ok to smoke......I've just got to watch the Lead intake :** laughs out loud **: Edit to add..... That pesky Rob_Beech beat me to it :( Link to comment Share on other sites More sharing options...
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