New Unleaded Solder - Can’t say I’m in love with it. - Page 1
Forum section: electronics / repair

author: Voxman
author_rank: Contributor
timestamp: October 28, 2020, 08:06:59 pm
content: Hi,Anybody out there have any negative feelings or experiences with the new standard lead free solder?I really don’t like it as it leaves a dull appearance instead of a nice shiny solder joint. It reminds me of a cold solder joint too much. I’ve attempted to heat the solder at a higher temperature but it still looks dull.I just bought 2 different types on the web and was using the Mandala Crafts on a receiver repair and was annoyed that the joints looked funky. The other Maiyum brand which isn’t lead free is just like my old solder that I recently ran out of.Question is did I just get a crappy lead-free solder or is this typical of all the newer lead-free solder being sold these days.Thanks for your input as always...Gary

author: Dubbie
author_rank: Unknown
timestamp: October 28, 2020, 08:32:11 pm
content: If it is just for personal repair jobs, save yourself the headache and use leaded.

author: KevinA
author_rank: Regular Contributor
timestamp: October 28, 2020, 09:36:44 pm
content: The regulations state that military and medical are exempt form using lead free solder - that should tell you something.Personally, I never used lead free, I stayed with standard 60/40 up to retirement.

author: thm_w
author_rank: Super Contributor
timestamp: October 28, 2020, 10:15:58 pm
content: It looks like better lead-free options are out there:https://hackaday.com/2020/01/28/lead-free-solder-alloys-their-properties-and-best-types-for-daily-use/But its still not SnPb level.

author: janoc
author_rank: Super Contributor
timestamp: October 28, 2020, 11:43:04 pm
content: It also helps to buy solder from a reputable brand and not Chinese specials.Lead-free is not great but if you compound it by cheap and crappy solder that is often not even meant for electronics (isn't Mandala Crafts specializing in jewelry and craft supplies?), you will only make you own life harder. There are plenty of posts on this forum about poor quality solders from Amazon, AliExpress, eBay, etc.

author: Miti
author_rank: Super Contributor
timestamp: October 29, 2020, 01:41:47 am
content: Lead free can be painful to work with. I almost always use leaded at work for things that don’t go to the customers and for personal projects in my home lab.However, I found one solder wire that is almost as easy to work with as it is with leaded. It was part of a commercial sample package that was not approved for production and was about to be recycled. It is rosin cored and we don’t use rosin in production. So I took it home. Other than the need to raise a bit the temperature, not much though, I can’t see any difference. I think rosin versus NC or washable makes a big difference.

author: Voxman
author_rank: Contributor
timestamp: October 29, 2020, 02:02:12 am
content: Thanks all for responding and the advice. I suspected something wasn’t quite right but wasn’t totally sure til now. I may try to send it back. I just wasn’t sure if it was set in stone that lead free was mandated and that was reason it was hard to find the leaded type.I don’t solder that much anymore but when I do I like it to be nice and clean shiny. I’m sure that stuff I have is probably for jewelry and it never crossed my mind - I need to pay better attention to what I’m buying these days. I’ll be looking for Kester brand as I remember it being one of the big names in solder.Thanks again!GaryLive and Learn

author: martinr33
author_rank: Frequent Contributor
timestamp: October 29, 2020, 04:26:17 am
content: That's a standard electronic solder alloy. Lead-free behaves as you describe.You have to look for the meniscus where the solder joins the lead or pad, not the shine.I find that sometimes a little extra flux helps, especially if the solder starts following the iron away from the joint, leaving a little spike.

author: exmadscientist
author_rank: Frequent Contributor
timestamp: October 29, 2020, 05:46:50 am
content: The flux is at least as important as the alloy. Half the reason Miti's solder is so nice to work with is the Sn100C alloy, which is generally considered "best of breed" for lead free alloys. (It makes those nice shiny joints we all love.) But the other half is that it's loaded with 3% of powerful flux: FCT's NC601 is a potent "RA" "Rosin Activated" type flux. In general "RMA" (Rosin Mildly Activated) is standard for fluxes, RA is one step up. Often the manufacturer will say you should clean RA flux residue off, but it's rare for that to be actually important. "No-Clean" fluxes are often impossible to clean off when you do need to do it, which can be annoying. This is getting better with more recent fluxes, or maybe the marketers are just labeling more things as no-clean.The other thing you should be aware of is that mixing solder types is very bad for joint strength. Getting a bit of lead in a lead-free alloy can really damage its mechanical properties. So if you are reworking leaded joints with lead-free, you need to get as much of the old solder out as possible. Going the other way is similar but a bit more forgiving. I have seen reworked joints where this was not done put under mechanical stress... and they split halfway down the middle of the joint, at the boundary between the two types of solder, not heated enough to mix. Oops.It's best, if you know what the old solder was, to just use more of the same.

author: helius
author_rank: Super Contributor
timestamp: October 29, 2020, 06:02:51 am
content: The specific problem with mixing lead-free with leaded types is not embrittlement: a mix of half of each type is actually less brittle than Sn62. The problem is that as the joint cools, the two types of solder pull apart and that can actually rip pads off the board.

author: janoc
author_rank: Super Contributor
timestamp: October 29, 2020, 09:44:28 am
content: Quote from: Miti on October 29, 2020, 01:41:47 amAh yes, SN100C. That one was mentioned in the Hackaday article too. The problem is that that composition is rare as hen's teeth because it was patented until recently. Mouser seems to be stocking it, though.

author: Shiv
author_rank: Regular Contributor
timestamp: October 29, 2020, 01:06:12 pm
content: I hate it.I have my own reserve of Sn62Pb36Ag2 and Sn60Pb38Cu2 (a bit harder) as the best I tested on hand repairs, but last time we couldn´t get it "legally".The leadfree we have is 96 and 97SC it needs much more heat and drops a lot of flux residue.I´ll keep plumbing.

author: elekorsi
author_rank: Regular Contributor
timestamp: October 29, 2020, 05:45:42 pm
content: Stay away from that if possible. For repair work or hobby just use the leaded one. I bought lead free solder once and threw it somewhere behind the bench, probably it is still there after some years...

author: wraper
author_rank: Unknown
timestamp: October 29, 2020, 05:48:38 pm
content: Besides Lead-free solder being harder to work with as such, solder you bough is dodgy as f**k.

author: David Hess
author_rank: Super Contributor
timestamp: October 29, 2020, 09:31:46 pm
content: Your experience is the same as mine so far; lead free solders are more difficult to work with.

author: tooki
author_rank: Super Contributor
timestamp: October 29, 2020, 10:04:40 pm
content: Quote from: Voxman on October 28, 2020, 08:06:59 pmYou got crappy solder.Quality lead-free flows nearly as nicely as leaded. We only use lead-free at work and honestly it’s just fine. But it’s quality solder. (No, it’s not quite as nice as leaded, but I think the people who describe it as horrible and unusable are wildly exaggerating.)The other thing to remember is that you must recalibrate your expectations of the appearance of the joint: lead free simply won’t make as shiny a joint. A satiny finish is acceptable. What you don’t want is dull.With that said, you’re in USA where leaded solder is still easy to obtain. IMHO there’s no reason not to buy a roll of Kester 44 63/37, which remains my all-time favorite solder. There’s no point in going with el-cheapo solder, given that the amount used in a project is insignificant.

author: wraper
author_rank: Unknown
timestamp: October 29, 2020, 10:10:11 pm
content: Quote from: tooki on October 29, 2020, 10:04:40 pmDepends on alloy. SN100C, it's clones and SnCu alloys are shiny or almost shiny. Anything containing silver is dull.

author: tooki
author_rank: Super Contributor
timestamp: October 29, 2020, 10:18:02 pm
content: Quote from: wraper on October 29, 2020, 10:10:11 pmBy “dull” I mean “matte”, which you should not be getting with any solder, even silver-bearing lead-free. Yes, there are differences in alloys, but the point here is that one cannot expect lead-free joints to be perfectly shiny, as is expected of a leaded solder joint.

author: wraper
author_rank: Unknown
timestamp: October 29, 2020, 10:31:23 pm
content: For some alloys being really 'matte' is normal. And REL61 (SnBiAgCu) from AIM is as dull as you can possibly get, yet it is mechanically stronger than any SnCu, SnPb or SnAgCu alloy widely used for electronics.https://aimsolder.com/sites/default/files/rel61_lead_free_solder_alloy_tds.pdf

author: tooki
author_rank: Super Contributor
timestamp: October 29, 2020, 11:57:04 pm
content: Those are all satiny, not the true matte of oxides.

author: wraper
author_rank: Unknown
timestamp: October 30, 2020, 12:04:26 am
content: Quote from: tooki on October 29, 2020, 11:57:04 pmREL61 I mentioned is basically grey. And you have some weird conception about what is matte.

author: james_s
author_rank: Super Contributor
timestamp: October 30, 2020, 04:49:03 am
content: I hate lead free solder. I always use the standard 60/40 stuff, it makes nice shiny joints with little effort. In the volume I use the stuff the lead is not a problem.

author: tooki
author_rank: Super Contributor
timestamp: October 30, 2020, 05:30:33 am
content: Quote from: wraper on October 30, 2020, 12:04:26 amNah, I’m pretty sure that my understanding of what the words “satin”, “dull” and “matte” mean in my native language (English) is exactly right.But once again: the point here is that one cannot expect lead-free joints to be perfectly shiny, as is expected of a leaded solder joint.

author: Voxman
author_rank: Contributor
timestamp: October 31, 2020, 06:43:10 pm
content: Again thanks to all for giving me insight into this issue.UPDATE: I’ve arrange to send back the lead free “crap” and have already received a nice 1lb. roll of Kester Sn60Pb40 rosin solder...which I’m very familiar with. I won’t be trying any more lead free or foreign made solders. I will say I’ve had some trouble finding the larger diameter solder that I like to use on larger solder joints. The largest I’ve found so far is .050 or 1.27mm... I would like at least a 1.5mm size but couldn’t find it on Amazon in Kester brand.But I’m happy I got the refund from Amazon although they said it was out of the return window...I whined a bit and they acquiesced to my request. And I didn’t mind paying double for the Kester roll (1lb size as opposed to the 100g size I returned) what the cheap stuff cost me.Thanks again everyone.Gary

author: Buriedcode
author_rank: Super Contributor
timestamp: October 31, 2020, 08:10:02 pm
content: Just another datapoint/view: I found SAC405 to be the most forgiving. That's 4% silver and 0.5% copper. The other reel I have is 3.9%Ag and 0.6% Cu, that also seems to work just fine.AFAIK these have a melting point of 217C, but frankly an iron on 320 means it really isn't much different from using leaded.I'll admit, on the rare occasions I've used leaded (on older equipment repairs, and with their own tips), it was a breeze. But you can still get nice shiny fillets with lead free, just needs to be a bit more expensive solder with half decent flux.

author: tooki
author_rank: Super Contributor
timestamp: November 01, 2020, 01:30:24 pm
content: Quote from: Voxman on October 31, 2020, 06:43:10 pmYou can always just take 2 or 3 strands of a thinner solder and twist them together for the occasional big joint. (If you're constantly using large solder, then it may be worth buying it. Amazon isn't always the best source, as they carry a fairly small selection of solder.)