Who would like to teach me about lead free soldering? - Page 1
Forum section: electronics / general

author: John Coloccia
author_rank: Super Contributor
timestamp: July 31, 2013, 05:24:09 pm
content: I may convert over to lead free solder because I think a lot of my customers will come from Europe. Someone talk to me about what I need to know. For example, if someon came to me and asked, "Hey, tell me about soldering", I'd start with, "Go out and buy Kester #44, 63/37. Buy a 186 flux pen. If you want to clean, you can use Chemtronics Flux Off Rosin followed by Ethanol/IPA blend. Set your iron somewhere between 650 and 750..." etc etc.I don't really know anything at all about lead-free soldering, different blends....does a eutectic lead free blend even exist? What about fluxes? Advantages/disadvantages to various types, etc. How do I clean afterwards? Basically just assume I know nothing about lead freeThanks for any help anyone offers

author: free_electron
author_rank: Super Contributor
timestamp: July 31, 2013, 06:03:47 pm
content: nothing different. buy kester lead free solder. it will have the right flux in it. set your iron the the recommended temperature. wash off with the same flux remover you use now.lead-free tips only differ in 1 aspect from non-lead free : they have a thicker iron plating as the higher tin content dissolves the iron faster. ( during soldering part of the iron in the tip dissolves in the solder joint. this is a required metallurgic process. the more tin the more iron is 'consumed'. so regular tips would wear out faster with lead free. so the plate them thicker.eutectic alloys exist. if you are going to do rework look at SN99c or SN100c. and by all means : stay away from SAC305. that is the 'shit' of the lead-free alloys.

author: Neilm
author_rank: Super Contributor
timestamp: July 31, 2013, 07:22:33 pm
content: If selling into Europe and having to use lead free, remember that you are limited to only a tiny amount of lead. So you can not have ANY contamination. A couple of years after the rules on lead free came into force one of the big manufacturers (Apple or Sony - that sort of size) got caught as they a few people using soldering irons with tips that had been using leaded solder.Neil

author: Smokey
author_rank: Super Contributor
timestamp: July 31, 2013, 07:30:31 pm
content: If you are getting boards professionally assembled (or plan to at some point), I highly recommend giving your assembly house a call and having a long talk with them. Tell them you are switching from leaded to lead free and ask what you need to look out for. It's in their best interest to help you out since if you get stuff wrong you could have problems ranging from damaged assemblies to poisoning their processes.Some examples are normal FR4 isn't setup for the higher temp needed in some RoHS reflow. You need high temp FR4, or something else. While this isn't as big of a deal these days you can also melt plastic connectors if they aren't rated. Another big issue would be mixing RoHS parts with non RoHS parts, especially the PCB finish. If you use leaded finish on the PCBs and that doesn't get caught before it gets run that through a Lead Free wave solder process or something, the assembly house will be really pissed at you.You would be surprised what doesn't pass RoHS sometimes, like the finish on screws/washers/nuts. Confirm everything.

author: Alexei.Polkhanov
author_rank: Frequent Contributor
timestamp: July 31, 2013, 07:36:33 pm
content: Use hot gas soldering with Nitrogen - joints will be as shiny as leaded ones. Sn95.5Ag3.9Cu0.6 is eutectic 217C solder. I hate dull solder joints and never use lead-free for hand soldering.Autectic property for all alloys is listed in a table on Wikipedia here:https://en.wikipedia.org/wiki/Solder

author: John Coloccia
author_rank: Super Contributor
timestamp: July 31, 2013, 08:20:53 pm
content: I'm hand assembling, and probably will be for the foreseeable future...probably forever, actually. I go back and forth. I may just say to hell with it, and just keep using lead solder. I'll leave it to the customer to figure out how to get it into Europe, and I'll just stay out of it.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: July 31, 2013, 10:51:05 pm
content: Quote from: John Coloccia on July 31, 2013, 08:20:53 pmIf your volumes are at the hand-solder level then just forget about it. Nobody will know or care.

author: G7PSK
author_rank: Super Contributor
timestamp: August 01, 2013, 08:29:09 am
content: If you are making industrial plant or tools the RoHs does not apply.http://en.wikipedia.org/wiki/Restriction_of_Hazardous_Substances_Directive

author: Sigmoid
author_rank: Frequent Contributor
timestamp: August 02, 2013, 07:13:11 pm
content: I think that if you're not based in Europe as a company, and aren't selling bulk to Europe then you don't have to worry about that sort of thing. Small-scale makers and hobbyists, like in the vintage computer demoscene in Europe keep selling hand-built stuff on eBay, without any ROHS certification. 99.9% of them uses oldschool leaded solder. (Yes you CAN buy the stuff in Europe.)That sort of thing is only for bulk. Nobody will start checking lead levels on a consumer mail-order PCB.As long as you aren't actually selling in stores in Europe, I'd say you shouldn't worry about environmental impact standards. And once you ARE selling in stores, you'll only be hand-soldering the prototypes.

author: Electro Fan
author_rank: Super Contributor
timestamp: August 03, 2013, 08:42:28 am
content: Quote from: John Coloccia on July 31, 2013, 05:24:09 pmI tried to read and research everything I could find on soldering - from users, vendors, you name it. Spent a fair number of hours on it.I came to the conclusion that I wanted to go with a Kester product - they seem to have a solid reputation and they make many versions. They have product literature that doesn't quit; I tried to wade through a ton of it.One of the things I liked about Kester beside the large number of advocates/happy customers/users they have is that they seem to make almost any flavor of solder you could want and within many of those flavors they have sub-flavors. So it wasn't like they had a particular axe to grind. Plus, their literature is really detailed - hard to believe a business could produce so many spec sheets on models of solder, but it helped me compare apples with apples and sometimes apples with oranges in a way that I could compare measureable attributes.At this point I knew I wanted Kester - but there were still a dozen or more variables to dial through. What was the stuff made of, what percentages, how well did it solder initially, at what temperatures, how easily did it clean up, how well did it perform, how did it look, how well did it hold up, how safe is it to handle, how safe is it for the environment, how much does it cost, etc, etc.In the process I found some papers and charts that were presented by Kester representatives at conferences that seemed to trace the thinking on various types of solders as they were introduced into the market over the last decade or so. I got pretty far into the weeds for a guy who just wanted to hand solder a few parts and boards here and there, but hey, I love researching.Finally I narrowed my questions regarding what I thought were the key concepts and tradeoffs involved and to a few of the potential products - so I called Kester's headquaters in the U.S. The first person I spoke with was pretty helpful but I got transferred around a bit (in a very helpful way as people could see I was after some specific info). Finally, someone suggested I call a particular rep - the name sounded like it might be the guy who developed and presented the papers at the conferences. I figured I was about to be in over my head but what the heck, I gave him a call.Turned out he was THE MAN - same guy who authored and presented the conference papers and charts. The fellow could not have been nicer or more helpful. I had done my homework so I kind of hung with him on the most of the details and he was patient with me to make sure I got it all crossfooted regarding the tradeoffs. By the end of an hour or so phone call he confirmed several things I had suspected and he straigthened me out on a number of other related considerations/tradeoffs. He even spent some time counseling me on the soldering irons I had under consideration.Long story short, I finally narrowed it down to three Kester products and gave them each a try in my lab (OK, in my garage); I had my own solder bake-off. See below (YMMV):Settled on this:Kester 24-9574-1402 Lead Free 48 RA Solder Wire, .031" dia., Core Size-66 Sn99.3Cu0.7 (K100LD)http://www.all-spec.com/products/KWLF4820.html- Lead free requires a higher temperature which I don't think is as desirable for parts and boards, but I decided LF was the right thing to do from a health and environmental standpoint. I'm confident that this model of solder represents an excellent balance of the many attributes anyone might be looking for in modern leading edge solder. So far every joint I've soldered with it conducts electricityTried this and it was ok but didn’t like it as much as Lead Free 48 above:Kester 24-9574-7618 Lead Free No-Clean 275 Solder Wire, .031" dia., Core Size-66 Sn99.3Cu0.7 (K100LD)http://www.all-spec.com/products/KWLF27540.html?gclid=CNiQ48_j4LgCFcdr7Aoda3cAWA- The solder joints didn't seem to form as easily/nicely as with LF 48Pretty sure this is the best but decided to go with Lead Free:Kester 24-6337-0027 44 RA Solder Wire, .031" dia., Core Size-66 Sn63Pb37http://www.all-spec.com/products/KW4410.html- This is probably the best (easiest/nicest/best looking solder joints at the lowest temperature) if you aren't as concerned about health and the environment---Here is a link to just Kester's Solder Wire products (they make many other products):http://www.kester.com/products/solder-wire/?type=in&limit=20&filters%5B%5D=&filters%5B%5D=18&filters%5B%5D=Within the Solder Wire products here are the Model 48 Flux-Cored Rosin Activated products:http://www.kester.com/products/product/48-Flux-Cored-Wire/"Kester 48 Activated Rosin Flux for cored solder wire was developed for lead-free applications to enable soldering of most common metals. Kester 48 has performance characteristics far exceeding standard RA fluxes. Kester 48 builds on the performance of its predecessor Kester 44"Note: the 10 digit part numbers don't use hyphens on the Kester site but on the web the hyphens seem to be generally used by Kester's distributors)

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: August 03, 2013, 11:38:57 am
content: QuoteIn terms of your health, you may find that LF flux fumes are nastier than leaded.There aren't really any issues with lead unless you eat it.

author: Electro Fan
author_rank: Super Contributor
timestamp: August 03, 2013, 11:11:13 pm
content: Quote from: mikeselectricstuff on August 03, 2013, 11:38:57 amHi Mike,That is a good point. My impression was that the 48 didn't "smell" quite as "nice" as the 44; smelling the 44 isalmostbut not quite pleasantly nostalgic. (I'd rate listening to 33 rpm records as more enjoyably nostalgic than smelling solder, even the leaded kind). For what it's worth, on the aromatic scale I thought the 48 was slightly more enjoyable than the 275, but neither are likely to replace after shave cologne.I think it's probably good to vent the soldering area if possible when working with LF (and maybe also with regular solder), and I wouldn't recommend eating either. Overall, I'm hoping that moderately low amounts of soldering with minimal inhaling and hopefully no eating results in safe learning and project development.EF

author: IanB
author_rank: Super Contributor
timestamp: August 03, 2013, 11:37:23 pm
content: Quote from: Electro Fan on August 03, 2013, 08:42:28 amExcept that from a health standpoint metallic lead is almost harmless. Heck, they made water pipes out of it for hundreds of years and nobody was dying.As to the environment, all the lead we use came from the natural environment in the first place. It is dug up out of the ground, extracted and purified. Returning it to the ground is just putting it back where it came from.The RoHS reglations on lead were basically put in place at the request of the electronics manufacturers to increase their sales volume. Lead free solder joints are far more prone to early failure than tin/lead solder joints (which are way too good, they last forever). Consumer device manufacturers need things to fail early and be replaced, and lead free solder is just the stuff to assist with that. The increased process costs of lead free manufacturing are far outweighed by the increase in revenues from new purchases. Why do you think the Japanese manufacturers went over to lead free voluntarily, without legislation? They knew that early device failure was a fantastic way to increase sales.The environment has suffered enormously from this of course, as the volume of electronic waste has grown hugely after the introduction of lead free.

author: nanofrog
author_rank: Super Contributor
timestamp: August 04, 2013, 08:48:29 pm
content: Quote from: IanB on August 03, 2013, 11:37:23 pmNot to mention the additional energy consumption involved in producing both the lead-free alloys themselves and products they're used in.

author: Smokey
author_rank: Super Contributor
timestamp: August 05, 2013, 08:12:11 pm
content: Quote from: IanB on August 03, 2013, 11:37:23 pmOur CM rep has TONS of stories about all the unforeseen consequences of RoHS. He was/is on the front line of it. The things that would shock most people not in the industry are the exemptions like..... Medical devices. I know they updated that recently so not all medical is excluded, but it's still funny that the reason most medical devices were allowed to contain unlimited amounts of toxic stuff was because RoHS assemblies were so unreliable compared to leaded and they couldn't tolerate failures in things like pacemakers. So your xbox can't have any lead, but the thing permanently implanted in your body can.And don't get me started with things like the history of tin whiskers