Which type of lead-free solder is the best? - Page 1
Forum section: electronics / general

author: dritech
author_rank: Contributor
timestamp: August 15, 2020, 09:59:36 am
content: Hi all,I intend to try soldering SMD components using lead-free solder (I know, some will say that I am out of my mind)I got two different price ranges when filtering for size 0.381 mm (0.015 in) and 63/37 :Three from AIM (33 euro average price)Three from Kester (all 69 euro)I never had any experience with AIM products. Are they any good, or should I just go for the more expensive Kester?Also, from the three options, which one would you choose? Unfortunately I do not have the knowladge to pick the best one for SMD soldering.Below are the links for the solder mentioned here:https://eu.mouser.com/AIM-American-Iron-and-Metal/Tools-Supplies/Soldering/Solder/_/N-b11qq?P=1yzxbyqZ1z0vtnpZ1z0jnibZ1z0zl9f&Ns=Pricing%7c0https://eu.mouser.com/Kester/Tools-Supplies/Soldering/Solder/_/N-b11qq?P=1yzxbyqZ1z0vtnpZ1z0jnibZ1z0zl9l

author: austfox
author_rank: Regular Contributor
timestamp: August 15, 2020, 10:17:45 am
content: Aren’t those links for leaded solder?

author: dritech
author_rank: Contributor
timestamp: August 15, 2020, 11:50:28 am
content: Okay, that just showed how inexperienced I am when it comes to selecting the correct type of solder. I saw the RoHS compliant symbol and assumed that they are lead free.Anyways, apparently the only lead free solder from Moser with a diameter close to 0.015" are three below (0.02"):https://www.digikey.com/products/en/soldering-desoldering-rework-products/solder/262?k=&pkeyword=&sv=0&sf=0&FV=-1%7C117%2C-1%7C82%2C76%7C4859%2C583%7C217368%2C1303%7C364091%2C-8%7C262&quantity=&ColumnSort=1000011&page=1&stock=1&pageSize=25I also found these from DigiKeyhttps://www.digikey.com/products/en/soldering-desoldering-rework-products/solder/262?k=&pkeyword=&sv=0&sf=0&FV=-1%7C117%2C-1%7C82%2C76%7C4859%2C583%7C217368%2C1303%7C364091%2C-8%7C262&quantity=&ColumnSort=1000011&page=1&stock=1&pageSize=25Which type would you recommend for general SMD soldering please?

author: austfox
author_rank: Regular Contributor
timestamp: August 15, 2020, 01:18:26 pm
content: I’ve been using Multicore (Loctite) branded lead-free for years, but in the 0.56mm size. Mouser sell this, as well as the 0.38mm size that you are after. It’s been fine for me, but I’ve only done a light amount of SMD soldering, mainly through-hole.I haven’t used any other branded solder so can’t advise you if it is better or worse than the others.Edit: Should have mentioned I’m using the 99C variant (99.3% tin, 0.7% copper).

author: tooki
author_rank: Super Contributor
timestamp: August 15, 2020, 01:40:57 pm
content: For whatever reason, buying lead free solder from USA to Europe is crazy expensive. You’d be much cheaper buying from a European vendor. (Also, for whatever reason, Kester’s price increase for really thin solder is much higher than many other brands.)I would suggest one of these:Rosin:https://www.reichelt.com/it/en/hs10-lead-free-solder-containing-silver-and-copper-0-5-mm-25-sta-hs10-tsc-0-5-p225655.htmlMore active no-clean:https://www.reichelt.com/it/en/crystal-511-tsc-sn95-sn95-ag4-0-5-mm-250-g-sta-511-tsc-0-5-p118604.htmlGentler no-clean:https://www.reichelt.com/it/en/lead-free-solder-containing-silver-and-copper-0-5-mm-250-g-sta-600-tsc-0-5-p217690.htmlThose are all 0.5mm. I really don’t recommend going thinner than that, you’ll find that you need ultra thin solder far less often than you might suspect. I have some 0.4mm and almost never use it (still on the roll I bought around 1990, and it’s still almost full!). Even for SMD, I use mostly 0.7-0.8mm, relying on flux and tip choice to ensure the right amount of solder.P.S. Those solders are all Stannol, which is the same as Multicore/Loctite, as they all belong to Henkel.December 2022 update: I’ve changed my mind. Having used Stannol a lot at work, I’m just not thrilled with it. Kester and Felder for the win.Also, it turns out Stannol is no longer affiliated with Multicore/Loctite. They had merged at one point, but Stannol was spun back off as its own company.

author: dritech
author_rank: Contributor
timestamp: August 15, 2020, 09:46:22 pm
content: I found a Multicore MM01876 which apparently was never used. I believe this is lead free solder, Do you recommend this for SMD? Should I use flux for best results?

author: eti
author_rank: Super Contributor
timestamp: August 16, 2020, 05:40:10 am
content: "Which type of lead-free solder is the best?"The type that ends up in the trash by the kilo.All this "eco" horse shit is precisely that. Lead-free solder = unreliable joints = shorter product lifespan = unjustifiable repeat sales = more revenue for the product manufacturer = more tax for the country.It IS that simple, don't let any "wise" speeches talk you out of it. It's a load of bollocks.

author: magic
author_rank: Super Contributor
timestamp: August 16, 2020, 08:56:15 am
content: That's all nice until you live in the EUSSR and would rather make electronics than drive a truck full of ANFO into the EUSSR Parliament. Some people prefer the former and we respect their choicePro tip: buy leaded solder while/if you still can because sales to consumers have been banned a few years ago. And if you are building commercial products, thenAnd if you think you are clever because you live in the UK, we shall see how your government screws you to stay "harmonized" with the EU because reasons.

author: GlennSprigg
author_rank: Super Contributor
timestamp: August 16, 2020, 02:27:53 pm
content: I can't help but generally agree...To 'me' Solder means 'lead'. I mean, we are talking about tiny amounts compared to the Massive amounts of 'Lead'used in numerous other types of industry. Does it really matter!!!So much MASSIVE reduction in the use of Lead these days, far out weighs the use of 'solder' at Home on a Cct Board..P.S. A few 'fun-facts'...The term 'Plumber', meant a Lead Worker, from the word 'Plumb' meaning 'Lead'. And a 'Plumb-Bob' was a 'Lead' weighthung from a string, in order to check the vertical accuracy, 90 deg from a 'Level'. Not much Lead work now, but glueingPVC pipes!!

author: tooki
author_rank: Super Contributor
timestamp: August 16, 2020, 02:32:04 pm
content: Quote from: dritech on August 15, 2020, 09:46:22 pmLooking it up shows it’s a SAC305 lead-free,which is basically the best lead free alloy. The flux is good too, so I’d say that’s a good solder if it’s already there.P.S. What stopped you from using google to find out this information yourself?December 2022 update: I’ve changed my mind. The SN100NiGe alloys, despite their higher melting point than SAC305, wet and flow so much better that I prefer using that instead.

author: tooki
author_rank: Super Contributor
timestamp: August 16, 2020, 02:34:28 pm
content: Quote from: eti on August 16, 2020, 05:40:10 amThis kind of hysteria is not helpful. It’s not what the OP was asking about, and it’s not even true. The worries about lead free solder being less robust aren’t proving to matter in the real world, where manufacturers quickly figured out how to use lead free just fine.Remember that by now, many of the lead free solder exemptions have expired.Is it as good as leaded? No. But is it the end of the world like you make it out to be? Absolutely not.

author: dritech
author_rank: Contributor
timestamp: August 16, 2020, 04:08:32 pm
content: Hi Tooki,Thanks for your reply.I did some research and many do not recommend using SAC305.Apparently K100LD and sn100c are better recommended if lead-free solder is required.Do you have any experience with these please? any advice?

author: ebastler
author_rank: Super Contributor
timestamp: August 16, 2020, 04:24:01 pm
content: Quote from: dritech on August 16, 2020, 04:08:32 pmThat sounds a bit enigmatic.Could you elaborate and ideally provide some sources please?

author: Bassman59
author_rank: Super Contributor
timestamp: August 16, 2020, 05:19:17 pm
content: Quote from: eti on August 16, 2020, 05:40:10 amOK, Boomer.

author: dritech
author_rank: Contributor
timestamp: August 16, 2020, 05:28:41 pm
content: Hi ebaster,Just to clarify, I did not do any scientific research, just reading comments from users (i.e. personal experiences)Just some highlights from just one forum (link below):https://www.eevblog.com/forum/beginners/solder-types/"If you really want to go lead-free in a lab environment get SN99c or SN100c. Stay far away from that SAC305 junk.""I've had good success with Kester K100LD. It's far better than SAC305 for wire solder.""It's the most common because it's cheap (certainly not the best performing). SN100C and K100LD are more recent, and the marketing literature insinuates performance is similar to 63/37 (i.e. good wetting, nice and shiny joints, low erosion, and cost effective)."

author: magic
author_rank: Super Contributor
timestamp: August 16, 2020, 06:33:32 pm
content: Quote from: tooki on August 16, 2020, 02:32:04 pm1% flux content and halide-free?I have been down that 1.1.3/ROL0 rabbit hole once. It's OK for assembling new boards with new components, less OK when using it on some old crusty equipment, oxidized connector etc. Maybe Multicore's is better but I wonder if your recommendation is based on that sort of use cases.

author: tooki
author_rank: Super Contributor
timestamp: August 16, 2020, 07:31:28 pm
content: Quote from: dritech on August 16, 2020, 05:28:41 pmFrankly, I think they’re wrong. Those >99% tin alloys all have appreciably higher melting points than SAC305. Shiny isn’t a useful goal in and of itself. Those solders may perform well in terms of wetting, but the higher melting point is a PITA.December 2022 update: I’ve changed my mind. The SN100NiGe alloys, despite their higher melting point than SAC305, wet and flow so much better that I prefer using that instead.

author: tooki
author_rank: Super Contributor
timestamp: August 16, 2020, 07:37:04 pm
content: Quote from: magic on August 16, 2020, 06:33:32 pmWhile I agree it won’t be good for old boards, FYI, it’s not a 1%. The datasheet you probably looked at (there are a few) merely states that a 1% version is available, but it’s not saying it’s the default.This datasheet (https://www.pemro.com/mmpemro/DataSheets/C400DS.pdf) makes it much clearer: as a 3-core solder, it’s 2% flux.

author: peter-h
author_rank: Super Contributor
timestamp: August 17, 2020, 08:56:05 am
content: For hand soldering, at work we tested many and far out the best was Almit from Japan. Very very expensive... Most of the others were horrible.For SMT reflow soldering, we use a subcontractor and I don't know what they use.

author: newbrain
author_rank: Super Contributor
timestamp: August 17, 2020, 09:04:51 am
content: Quote from: eti on August 16, 2020, 05:40:10 amBollocks.I work in a place that designs and produces electronic equipment which is sold by the million units and used all over the world, in all kind of internal and external environments.Replacement cycles can be long or short, but we have a lot of very old stuff around.When we made the move to lead free (and all the rest of Rohs), there were some teething problems - as with any process change: I still remember some early BGA based boards...To my knowledge, we have not experienced any increased field failure rates or returns due to lead free solder, and I've never seen a recall issued specifically for Rohs related problems on the stuff I worked on.

author: Simon
author_rank: Unknown
timestamp: August 17, 2020, 05:18:47 pm
content: Lead free is no longer an issue although the old folk like to rat on it. The early days were bad i hear but that's over, we have had years of lead free.

author: eti
author_rank: Super Contributor
timestamp: August 17, 2020, 10:26:23 pm
content: Quote from: newbrain on August 17, 2020, 09:04:51 amOkay then

author: peter-h
author_rank: Super Contributor
timestamp: August 18, 2020, 09:10:58 am
content: The issue of whiskers never actually went away.I think the reason why it is not a problem today is that packages with pins on the periphery (QFP etc) never went below about 0.5mm pitch. I had seen some 0.35mm but that was in the leaded solder days and it was OK then. The high pin count stuff went to BGA where the balls are not that close so the problem was avoided.Whiskers could also be avoided with special conformal coatings but they are expensive.Military and medical still have exemptions. In fact I think the whole "control and monitoring equipment" exemption may still be there; if not then it ended quite recently. A huge raft of small manufacturers were operating under that. And if you are using up old component stock then you have to because the pins can be tin/lead plated.For hand soldering, leaded solder works much better. However a lot of the challenge is the flux composition and this is where the super pricey Almit solder works quite well. But it works only as well as the cheapest dirtiest no-brand-name leaded solder which is 1/10 of the cost.The whole ROHS thing is pointless because lead from other sources (e.g. car batteries) is vastly bigger than lead getting into the environment from electronics.

author: perieanuo
author_rank: Frequent Contributor
timestamp: August 18, 2020, 10:58:53 am
content: hi,my 2 cents: if the law says you have to work with lead-free, ok.if not, take a good 60/40 Sn-Pb alloy.I haven't see any lead-free that beats 60/40.regards

author: ebastler
author_rank: Super Contributor
timestamp: August 18, 2020, 11:16:09 am
content: Quote from: peter-h on August 18, 2020, 09:10:58 amRoHS exemptions for medical equipment ended in 2016, and for monitoring/control equipment in 2014 (except industrial instruments) and 2017 respectively (industrial).You can't legally use up old component stock any longer. The only exception applies to their use as spare parts for units which were placed on the market before the relevant RoHS effective date.

author: newbrain
author_rank: Super Contributor
timestamp: August 18, 2020, 11:39:24 am
content: Quote from: perieanuo on August 18, 2020, 10:58:53 amAnd 63/37 shreds both!

author: Psi
author_rank: Super Contributor
timestamp: August 18, 2020, 11:42:16 am
content: Best lead free solder is mislabeled leaded solder

author: peter-h
author_rank: Super Contributor
timestamp: August 18, 2020, 02:37:03 pm
content: The proof of the pudding (an English idiom) is that 60/40 etc is still widely sold e.g.https://www.rapidonline.com/rapid-solder-wire-60-40-22swg-0-7mm-500g-reel-85-0595When ROHS came in, the price rocketed, presumably because everybody was stocking up with itIt went from £5 to over £20 / 500g, very fast. Making money out of compliance is the world's second oldest profession.Unleaded SMT soldering was originally a huge issue for capacitors, due to the higher soldering temperatures. Electrolytics from the biggest quality names e.g. Nichicon would "inflate" from the gases liberated. This would have triggered the scrapping of a lot of component stock. The general quality never reached the perfect wetting one got with leaded solder, but it works well enough for nobody to bother anymore.

author: Bassman59
author_rank: Super Contributor
timestamp: August 18, 2020, 05:22:23 pm
content: Quote from: peter-h on August 18, 2020, 09:10:58 amIt's not pointless.Car batteries are pretty much always recycled. When you buy a new battery here in the colonies, the seller takes your old battery and deals with the recycling. There's a lot of lead in them and it's valuable. Sure, you have jackasses who don't trade in the batteries, but then the seller adds a "core charge" to the price of a new battery if there is no trade-in.Consumer electronics are something else entirely. When a gizmo dies, most people just toss it into the trash, and the trash gets hauled off to a landfill. And the problem is that the lead and other heavy metals were leaching into the water supply from landfills.Think about how many electronic things you have in your house, and then multiply that by all of the homes in your city. That's a LOTTA e-waste.

author: tooki
author_rank: Super Contributor
timestamp: August 18, 2020, 06:56:19 pm
content: Except that the numbers used for calculating the lead in electronics was based on the numbers including CRT glass, which contains severalkilosof lead per tube! But by the time RoHS took effect, CRTs had already gone the way of the dodo, leaving only a few grams of lead in a device, at most.And meanwhile, literally TONS of lead continues to go into the environment in lead bullets from hunting and target practice.So yes, RoHS’s lead restriction is entirely pointless in the context of electronics.

author: Kilo Tango
author_rank: Regular Contributor
timestamp: August 18, 2020, 08:29:38 pm
content: I use SM100C for lead free applications, OK it needs a hotter temp but its qualities match the filleting effect you got with 60/40, esp if you lowered the temperature a bit.....Not all in the world of lead free is perfect, a chap hereat 4:08, removed an assembled PCB from its carrier and 4 SMD LED's "fell off". Lead free solder is only there to make a contact, 60/40 adds significant mechanical strength via the joint fillet. I have an old Marshall 10W valve amp, dear knows how old, yet it still works well, and it was built with Lead Solder. Valve amps are fairly hostile environments.Ken

author: peter-h
author_rank: Super Contributor
timestamp: August 18, 2020, 09:10:49 pm
content: Certainly you need a better process for lead free reflow soldering, to get the low defect rate which we took for granted with leaded reflow, or with PTH flow (wave) soldering.And some components don't solder. Shelf life often becomes critical, when it wasn't with leaded. I have had varistors from Littelfuse which had problems. Even brand new. The mfg must have discovered this was a real issue and they started putting silica gel sachets into the bags...The stuff about landfills depends very much on the landfill. Modern landfills don't have water running through them - for obvious reasons. So the story about metals leaching out of electronics is not true, via this route.The EU regulatory apparatus has to introduce regulation all the time - it's its jobThey will never stop.

author: Red Squirrel
author_rank: Super Contributor
timestamp: August 20, 2020, 12:17:51 am
content: One thing I feel is needed is better electronics recycling and lead would be less an issue. Not just lead but really the entire circuit boards themselves including components. As far as I know there is not really any methods to recycle circuit boards right now and that is kind of a big problem as they are just filling landfills. Lot of the electronics recycling places don't actually recycle, they just send it to china, then who knows what they do with it, probably dump in the ocean.

author: pidcon
author_rank: Contributor
timestamp: August 22, 2020, 01:44:57 pm
content: In the past, I went through this endless cycle of switching between different lead-free formulations too. Regardless of the formulations for lead-free solder (SAC305, SAC405, Sn99Cu1, etc.) I would focus more on the lead-free offerings from reliable brands, such as Kester, Multicore, Stannol, and so on. If the work is for a hobby, then try whichever you like based on cost and ease of purchasing. If it's for business, then write to the solder manufacturer and ask for their advice.

author: nukie
author_rank: Frequent Contributor
timestamp: August 26, 2020, 02:19:52 am
content: SN100C by Nihon Superior with their in house flux. This formulation is available from other brands under license. This is by far the best LF solder I tried.When trying new solder, it's best to 'wash and rinse' the tip with plenty of new solder so the previous solder does not contaminate your new solder. The solder alloy composition is very important and if it's thrown off balance the performance will not be the same.Use a new cleaning pad after the tip is 'cleaned' because it may pickup another type of solder pieces on the used cleaning sponge.

author: SiliconWizard
author_rank: Super Contributor
timestamp: August 26, 2020, 05:55:27 pm
content: Quote from: ebastler on August 18, 2020, 11:16:09 amActive implantable medical devices are still exempted, though.

author: SiliconWizard
author_rank: Super Contributor
timestamp: August 26, 2020, 05:57:53 pm
content: For manual SMD assembly, I mostly use Multicore 3C, 0.23mm. I use thicker wire (0.6mm) only for the larger parts/wiring/etc.

author: Calambres
author_rank: Frequent Contributor
timestamp: August 27, 2020, 03:37:57 pm
content: Quote from: peter-h on August 18, 2020, 09:10:58 am...and AeroSpace. Otherwise flying airliners would be a no-no for me