Good lead free solder for hand soldering - Page 1
Forum section: electronics / general

author: peter-h
author_rank: Super Contributor
timestamp: January 24, 2022, 12:18:20 pm
content: A while ago I evaluated a load of LF solders and found them to be basically crap, except Almit LFM48S - Japanese.This has gone up to £100 for 0.5kg which is ridiculous. It is about 10x of leaded solder, and all prototyping is done with leaded because it works so much better, but for stuff that goes out of the door we have to use LF, just in case somebody checks.Can anyone recommend a really well flowing LF solder?Someone recommended Stannol from Germany but it is the same price as Almit.

author: kayvee
author_rank: Regular Contributor
timestamp: January 24, 2022, 12:31:53 pm
content: I presume you are talking about wire, we use Kester K100LD 0.8mm wire, which gives us great results.For lead-free paste we use with Alpha OM-338T (S3).

author: peter-h
author_rank: Super Contributor
timestamp: January 24, 2022, 03:42:53 pm
content: WOW that costs even more than Almit: £91 for 1lb (0.45kg) inc VAT.

author: bdunham7
author_rank: Super Contributor
timestamp: January 24, 2022, 04:05:41 pm
content: I have a roll of AIM SN100C Glow Core which I use for the occasional lead-free task. I would rate it as acceptable on new, shiny components and usable on repairs with some supplemental flux-pen cleaning. I only have it in 1.0mm because I spotted it in surplus dealer (All Electronics). I suspect if you had to buy it through normal sources at 0.8 or 0.5mm it would also be fairly expensive. However, I don't see where you get 10X the cost of leaded--here a pound of Kester 44 Sn/Pb eutectic is about $30 or so, the K100LD is $60 or so and the 44 Sn/Pb/Ag is $90-ish.https://www.amazon.com/Kester-24-9574-7610-Lead-Free-Solder-020-Diameter-Low/dp/B00FGHTX5A/ref=sr_1_3?crid=2JHLZ790KUMJO&keywords=k100ld&qid=1643040226&sprefix=k100ld%2Caps%2C129&sr=8-3

author: jc101
author_rank: Frequent Contributor
timestamp: January 24, 2022, 04:34:25 pm
content: I've moved to Solderking, UK made, 0.5Kg ~£55 in VAT (https://kaisertech.co.uk/products/soldering/solder-wire-and-flux/solder-king-solder-flux?wire_diameter=0.70mm). They may even send you a free sample if you drop them a line.

author: peter-h
author_rank: Super Contributor
timestamp: January 24, 2022, 04:45:23 pm
content: You are right - prices have gone up a lot lately. It is more like a 5x difference. I can get 500g reels for £20 e.g.https://www.rapidonline.com/warton-metals-omega-63-37-low-residue-1-flux-solder-wire-20swg-0-914mm-500g-85-6162Yes indeed most LF solders seem to work ok only under ideal conditions and at quite a high bit temperature.Thanks for the Solderking tip. I have just emailed them. If they work, they are about half the price of the others.

author: jc101
author_rank: Frequent Contributor
timestamp: January 24, 2022, 04:47:39 pm
content: I tried Warton but I didn't like the result, so far the Solderking SAC305 0.7mm has been good to work with. Next time I need some paste I'll get a tub of theirs too.

author: mazurov
author_rank: Frequent Contributor
timestamp: January 24, 2022, 06:47:07 pm
content: This is what I use, likely the same @kayvee recommends but I can't figure the PN."Well flowing" depends on operator's skills, if you can't find one you may want to reevaluate your technique.

author: peter-h
author_rank: Super Contributor
timestamp: January 26, 2022, 11:26:46 am
content: Kester is well known but also 100 quid for 500gSomeone mentioned SAC305 is not needed for hand soldering i.e. no need for any silver. Tin and copper is enough and it is the flux that matters most.Well, I agree re the flux because when I tested a load of SAC305 solder wire samples, most were useless and only the Almit one worked, but that is also SAC305, so it has to be theflux.

author: david77
author_rank: Frequent Contributor
timestamp: January 26, 2022, 11:38:09 am
content: I don't do much lead free soldering but found this to be quite good:https://www.felder.de/products/electronic-applications/wave-soldering-selective-soldering/nige-solder-sn100ni-snag-sn100c/loetdraht-iso-core-clear-5552940520.html

author: peter-h
author_rank: Super Contributor
timestamp: February 04, 2022, 05:20:16 pm
content: Just tested thisand it works well. I'd say similar to the Almit one. More tests to come.

author: tooki
author_rank: Super Contributor
timestamp: February 26, 2022, 10:59:27 am
content: Try Felder. I like it better than Stannol, and it’s appreciably cheaper.E.g.https://www.pmtech.co.uk/solder-wire-felder-iso-corear-lead-free-sac387-250g-reel.html

author: wraper
author_rank: Unknown
timestamp: February 26, 2022, 11:18:21 am
content: I don't like Stannol at all. They use some crappy fluxes which either produce some dark residues and burned junk on a solder tip, and/or splatter a lot. First of all you should look on what alloy is used. SnCu alloys flow much worse than SAC305, SAC307 and SN100C and it's clones like K100LD (unless used with active fluxes). SN100 probably produces the nicest solder joints and flows very well. SAC307 is the cheapest of what I mentioned. Regarding the quality of flux, and which is priced reasonably, I like solder produced by Alpha.

author: tooki
author_rank: Super Contributor
timestamp: February 26, 2022, 11:41:21 am
content: Quote from: wraper on February 26, 2022, 11:18:21 amExactly my experience. The spitting is really annoying.

author: nctnico
author_rank: Super Contributor
timestamp: February 26, 2022, 01:24:39 pm
content: Multicore C 502 99C 5C works well for me. With the iron set to 330 deg. C.; from my experience lead-free solder is much more cricital where it comes to using the right temperature.

author: forrestc
author_rank: Unknown
timestamp: March 04, 2022, 09:49:49 pm
content: We use an indium cored wire which works fairly well... Don't know if that's availableHowever, what we've found works better is tacky flux such as indium tacflux 020, in a tiny syringe with a microscope. Put just barely enough on each joint, then solder with non-cored wire.

author: KE5FX
author_rank: Super Contributor
timestamp: March 04, 2022, 10:11:45 pm
content: For home use? Order 63:37 solder from the US and wash your hands after using it.

author: IanB
author_rank: Super Contributor
timestamp: March 04, 2022, 10:28:24 pm
content: I didn't see any mention in this thread, but when talking about hand soldering results, is that with or without extra flux?It may well be that relying on the flux in the solder core alone is limiting, and that application of extra flux is important?Even with leaded solder, I have been in the habit of using additional flux when I want really nice results. I have also found it critical to clean/polish solder pads with a suitable abrasive to remove any oxide layer before soldering.

author: peter-h
author_rank: Super Contributor
timestamp: March 11, 2022, 11:08:10 am
content: QuoteYou can buy it easily here in the UK - "for industrial use only"The key to unleaded solder working well is the flux. We have tested different SAC305 hand soldering wire and some is useless and some (Almit) is almost as good as leaded but at a silly price.The above Solder King stuff is poor, on initial tests, but we need to try different bit temperatures.

author: jc101
author_rank: Frequent Contributor
timestamp: March 11, 2022, 11:18:42 am
content: I've found the SolderKing CXW to be OK, the data sheet gives 350c-360c as the tip temp. Running at 350c so far has been good for me. By all accounts the company is happy to visit potential customers and help with testing and setups etc. to get the best from their products, which I think is free.I don't do huge amounts though, when I do need to do hand soldering it's normally intensive for a few days depending on the project.

author: peter-h
author_rank: Super Contributor
timestamp: April 19, 2022, 01:51:15 pm
content: I can confirm the above Solder King stuff is OK at 340C.

author: tepalia02
author_rank: Regular Contributor
timestamp: April 19, 2022, 01:59:18 pm
content: You can consider this one :https://www.sparkfun.com/products/9325

author: nigelwright7557
author_rank: Frequent Contributor
timestamp: April 19, 2022, 04:18:04 pm
content: They used lead free solder on satellites for a while.Then to their horror found it starts to whisker over time causing shorts.

author: tooki
author_rank: Super Contributor
timestamp: April 20, 2022, 10:36:48 am
content: Quote from: nigelwright7557 on April 19, 2022, 04:18:04 pmI don’t believe that chain of events for a second, since the aerospace industry investigated tin whiskers long, long before the move to lead free. What has been found are tin whiskersfrom pure tin platingon component legs.

author: peter-h
author_rank: Super Contributor
timestamp: April 21, 2022, 10:22:37 am
content: I think the whiskers story is more complicated, but I am not sure how it went.For sure the issue got gradually sidelined by leg pitch not going below 0.55mm (the Japs went down to 0.35mm but it didn't last long) and then the big chips went to BGA which has huge spacing.The worst whiskers were found where the substrate wasstressed after tin platinge.g. extruding the old metal transistor cases from tin plated sheet. Where the plating was done after the substrate forming, the situation was a lot better.That Sparkfun stuff is in the USA.

author: lfldp
author_rank: Regular Contributor
timestamp: June 10, 2023, 06:47:44 pm
content: Quote from: wraper on February 26, 2022, 11:18:21 amhi i agree lead-free solder wires should contain agressive flux to keept valid temperature do you think this one will be ok ?https://www.tme.eu/pl/en/details/hf850sac305-075_05/solder-wires-lead-free/alpha/sac305-telecore-hf-850-122-0-75mm-500g/thanks

author: Monkeh
author_rank: Super Contributor
timestamp: June 10, 2023, 07:13:36 pm
content: I've been using a bit of Weller wire solder in SN99.3/CU0.6/NI0.05 for some work recently and been quite happy with it. It looks like they might have discontinued the alloy, though? CPC still have some stock including little sample packs. Very aggressive flux. It is also nearly £20 for a 100g roll, though.

author: lfldp
author_rank: Regular Contributor
timestamp: June 11, 2023, 07:19:28 am
content: Quote from: Monkeh on June 10, 2023, 07:13:36 pmnot available in my country

author: lfldp
author_rank: Regular Contributor
timestamp: June 11, 2023, 07:25:15 am
content: funny thing i did some tests last night and i dont see completly any difference in soldering quality for beetwen cheap and expensiff solder wires:1. stannol SN100C - with nicel and german SnCu0,7NiGe - expensiff price few times higher than cynel brand !2. cynel professional sn99,3Cu0,7 - cheap oneboth of them loose flux very quickly on under the fume hood and im getting thin whiskers also flow of this tin seems is sameso ?

author: tooki
author_rank: Super Contributor
timestamp: June 11, 2023, 03:19:55 pm
content: Quote from: lfldp on June 11, 2023, 07:25:15 amNo you’re not. Tin whiskers take years to grow, in the rare cases they do. (Normally from pure tin plating, not from solder.)Anyhow, Stannol isn’t cheap, but honestly I don’t particularly like it. I like Kester for leaded, and Felder “SN100Ni+” (SnCuNiGe).It’s all about the flux, and IMHO Stannol just isn’t that great in that regard.

author: Neomys Sapiens
author_rank: Super Contributor
timestamp: June 12, 2023, 04:36:41 am
content: I recommend Balver Zinn Brilliant B2012. It is the best lead-free solder that I have encountered. When they demonstrate it, you are even encouraged to try it on stranded wires and connectors. IME this is where most others fail.

author: lfldp
author_rank: Regular Contributor
timestamp: June 12, 2023, 06:44:27 am
content: Quote from: Neomys Sapiens on June 12, 2023, 04:36:41 amok thx will try it soon

author: tooki
author_rank: Super Contributor
timestamp: June 12, 2023, 09:52:24 am
content: Quote from: Neomys Sapiens on June 12, 2023, 04:36:41 amWhich one? B2012 comes in five different lead-free alloys. The alloy I would expect to perform best is the SN100C (SnCuNiGe).

author: Neomys Sapiens
author_rank: Super Contributor
timestamp: June 13, 2023, 07:37:19 am
content: Quote from: tooki on June 12, 2023, 09:52:24 amConcur - I forgot to mention this. The one I have actually used is the SN100CV. I have a sample of the SN100C also, but have not compared them yet.

author: tooki
author_rank: Super Contributor
timestamp: June 13, 2023, 11:03:43 pm
content: Quote from: Neomys Sapiens on June 13, 2023, 07:37:19 amThe SN100CV is a strange alloy (SnBi1.5Cu0.7).I've used SN100C from Felder, and it's the best lead-free alloy I've tried so far. Despite not having the lowest temperature (that'd be SAC305, if we ignore SnBi low-temp alloys), it wets the best, practically as well as leaded solder.

author: lfldp
author_rank: Regular Contributor
timestamp: June 14, 2023, 09:56:13 am
content: Quote from: tooki on June 11, 2023, 03:19:55 pmagain i mean mustache by saying tin whiskersIt’s all about the flux - you mean ammount of flux or flux type ?

author: tooki
author_rank: Super Contributor
timestamp: June 15, 2023, 07:33:42 pm
content: Quote from: lfldp on June 14, 2023, 09:56:13 amI have no idea what you are trying to say.Quote from: lfldp on June 14, 2023, 09:56:13 amFlux formulation. (I suppose the amount matters, too, in that the amount needs to be appropriate for the type of flux.) I haven’t been impressed by Stannol’s fluxes, neither in activity nor in other aspects (I find it spits more than other brands I’ve used, and their rosin fluxes burn sooner than I’m used to compared to other brands I use).

author: IanB
author_rank: Super Contributor
timestamp: June 16, 2023, 02:51:05 pm
content: Quote from: tooki on June 15, 2023, 07:33:42 pmWhen you draw the iron away from the joint it pulls whiskers of solder (like spikes) away from the joint. This happens when the flux is no longer active and functioning.IMHO, this situation can be improved by using extra flux on the joint. It is not always sufficient to rely solely on the flux in the solder core.

author: tooki
author_rank: Super Contributor
timestamp: June 17, 2023, 07:31:51 am
content: If he means spikes, then he should say spikes. “Whiskers” in the context of solder has an existing, very specific meaning.

author: lfldp
author_rank: Regular Contributor
timestamp: June 17, 2023, 10:31:59 am
content: Quote from: tooki on June 15, 2023, 07:33:42 pmi agree with you1. stannol flux is totally crap2. from my own past experiments with lead-free bga reballing results about only few models of flux could manage lead-free (keept temperature for so long) for example amtech syntech-lf-tf is my favorite flux this flux is designed only for lead-free soldering , the other fluxes which i tryin like aim nc254 also other amtech's they dont exactly effective for lead-free like syntech-lf series

author: lfldp
author_rank: Regular Contributor
timestamp: June 17, 2023, 10:35:52 am
content: Quote from: IanB on June 16, 2023, 02:51:05 pmhehe exactly this was what i mean before , anyways in my case even extra flux manually added by me to solder wire could not help me to fix this problem because i soldering under fume hood and before i can put tip with extra flux to solder joint it evaporating faster ! so for me there should be extra flux added directly to solder wire , do anyone tryin solder wires made by amtech with syntech flux incliuded ? does these soldering wires are worst its price ?

author: tooki
author_rank: Super Contributor
timestamp: June 17, 2023, 01:58:18 pm
content: There are several things that promote spikes: oxidation, contamination with dissolved metal (like copper from the component leads, gold plating, etc.), temperature, and time.Oxidation and contamination change how the solder behaves, causing it to get spiky, so you want to prevent these things.Too low a temperature can cause spikes because the solder is barely melted and surface tension can’t pull it back.Too high a temperature increases oxidation and increases contamination.—> You need a temperature that is as low as possible, but as high as necessary. A larger soldering iron tip (and/or board preheating) let you use a lower tip temperature.Flux prevents oxidation (and to an extent reverses it). So you need good flux in sufficient amounts. It doesn’t remain active forever, so if you’re taking a while on a joint, your flux may “wear out” and you will need to add some fresh flux.And finally, experience lets you work faster, reducing the time it takes to make the joint — time when flux is wearing out, and oxidation and contamination are occurring.If you have spikes forming, and even adding fresh flux doesn’t help, stop. Get rid of oxidized, contaminated solder from the tip (and maybe even the joint, too): Melt lots of fresh solder onto your tip and wipe it off. Do this a few times to rinse off all the oxidized, contaminated solder. Then go back and try to rework the joint with fresh solder and fresh flux.It takes practice to figure out what temperature is right for each solder, tip, and even the joint itself.

author: tooki
author_rank: Super Contributor
timestamp: June 17, 2023, 01:59:17 pm
content: Quote from: lfldp on June 17, 2023, 10:35:52 amThe fume hood isn’t likely to make any difference whatsoever, in that the flux isn’t so much evaporating as it is burning off.

author: lfldp
author_rank: Regular Contributor
timestamp: June 18, 2023, 06:46:00 pm
content: Quote from: tooki on June 17, 2023, 01:59:17 pmok but in short i have problem like that - i can only correctly solder by lead-free wire if i smear pcb with externall flux so maybe the problem is with valid lead-free solder wire model ? soon ill try this SN100Ni+ maybe it will be ok to fix my problem

author: lfldp
author_rank: Regular Contributor
timestamp: June 18, 2023, 06:46:59 pm
content: Quote from: tooki on June 17, 2023, 01:58:18 pmYou need a temperature that is as low as possible, but as high as necessary. A larger soldering iron tip (and/or board preheating) let you use a lower tip temperature. > ok will try this solution too

author: tooki
author_rank: Super Contributor
timestamp: June 20, 2023, 06:32:50 pm
content: Quote from: lfldp on June 18, 2023, 06:46:00 pmWhat temperature are you using? What kind of tip? What kind of joint? What technique? How old are the components? While external flux can make it easier to make nice joints, it really shouldn’t be necessary for THT soldering (and some SMD soldering).

author: IanB
author_rank: Super Contributor
timestamp: June 21, 2023, 03:05:43 pm
content: Quote from: lfldp on June 17, 2023, 10:35:52 amBut you don't add extra flux to the solder wire, you add the flux to the joint (to the PCB and component being soldered).Quote from: lfldp on June 18, 2023, 06:46:00 pmIt is quite normal to add flux to the PCB before soldering, especially if working with SMD parts. If you watch videos, you will see the usual practice is to flood the PCB with liquid flux.

author: lfldp
author_rank: Regular Contributor
timestamp: June 22, 2023, 08:31:33 pm
content: Quote from: tooki on June 20, 2023, 06:32:50 pmi usually use 360c

author: lfldp
author_rank: Regular Contributor
timestamp: June 22, 2023, 08:33:24 pm
content: Quote from: IanB on June 21, 2023, 03:05:43 pmok and you know good liquid flux for lead-free ? i remember in past i tryin something like thathttps://termopasty.pl/produkty/topnik-rf800/and this flux was no good for lead-free rather for leadded soldering

author: tooki
author_rank: Super Contributor
timestamp: June 23, 2023, 08:49:20 am
content: Quote from: lfldp on June 22, 2023, 08:31:33 pmOK. And what about the 4 further questions I asked?

author: forrestc
author_rank: Unknown
timestamp: June 27, 2023, 11:42:28 pm
content: Quote from: lfldp on June 22, 2023, 08:33:24 pmI'm a fan of Indium TACflux 020B or 089HF. 089HF works well but you have to either clean it or make sure it's 100% activated before leaving it on the board. 020B is a little less active, but residues are safe even if they have not been activated. Note activated means brought to soldering temperatures. Generally I'll use 089HF when I'm 100% sure I'm going to be able to get all of the flux activated - tiny applications to a joint is a good example. I use 020B when I'm not 100% sure, such as when debridging a joint where some of the flux may end up under the component and may never get removed.Avoid any flux which says "water clean". Water clean = must clean, and residues (even if heated) typically are active and will eat components over time. There are a few out there which claim that residues are safe to leave, but they are few and far between, and haven't tried any I like. Basically a "no clean" flux hardens to a plastic-like substance which is safe to leave on the board except in some critical applications.

author: lfldp
author_rank: Regular Contributor
timestamp: June 28, 2023, 07:06:05 pm
content: Quote from: tooki on June 23, 2023, 08:49:20 amtoday i received felder sni100+ and i can confirm this is exactly what i need! its flux works enough long and i didnt getting anymore joints with so called moustaches , the stannol sn100lc solder wire is totall crap in this case or i have expired one but anyways as i remember this solder wire works very poor from begining (one year ago) problem with this solder wire is like i said it lost very fast its own flux and i getting moustaches by it , also its flow is not even comparable with felder sni100+ ! thanks for previous recommendations , last question - does solder wire or its own flux have some kind of expiry date ? or it can be used even after few years ?

author: lfldp
author_rank: Regular Contributor
timestamp: June 28, 2023, 07:10:21 pm
content: Quote from: forrestc on June 27, 2023, 11:42:28 pmwell ok thanks also for yours recommendations ill try also this flux and btw. the water washable flux so called water soluble they are no good for me and long time i stopped use them , offcourse they give much more less contaminated fumes than usuall flux but have one problem - they are very high active and could for example warp pcb especially if you soldering bga with them could also damage solder mask with wires easy for example the one ive using in past was amtech lf-4300 original one

author: forrestc
author_rank: Unknown
timestamp: June 28, 2023, 08:33:13 pm
content: Quote from: lfldp on June 28, 2023, 07:10:21 pmI'm not aware of ANY solder pastes which are from reputable solder manufacturers (Kester, Indium, Amtech, etc.) which will warp the PCB or damage solder mask. Eat away copper and cause corrosion and/or surface resistance failures, but not PCB warpage or solder mask.Generally warping and/or solder mask damage has to do with improper (too hot or uneven) application of heat, or in the case of solder mask damage, mechanical "scuffing" of the mask when hot. Now, with that in mind - using incorrect paste will often result in the operator having to apply too much heat to get a BGA off or similar, causing the damage you describe. But it's not the paste, it's the heat.Note that if you need to rework a BGA, you need to make sure you have a flux which will flow under the bga and still be active when it reaches the balls you need to melt. The tacflux that I mentioned will do this, but you'll probably want to be careful to use the hot air to "push" the flux under the bga.

author: tooki
author_rank: Super Contributor
timestamp: July 02, 2023, 06:58:24 pm
content: Quote from: lfldp on June 28, 2023, 07:06:05 pmGlad you're happy with it!Which flux? They sell the Sn100+ alloy with at least two kinds of flux.Quote from: lfldp on June 28, 2023, 07:06:05 pmMost manufacturers list an expiration date or manufacturing date on the package. They guarantee performance only until the expiration date or for a certain number of years after the date of manufacture. Super-critical customers like aerospace and military will discard the solder after that. But for normal use, it lasts forever. I have top-brand (Kester) solder I bought in the early 1990s and it still works like new. I don't have any solder wire younger than 2015.The only thing that could be an exception (this is purely speculation on my part) is water-soluble fluxes. I can imagine that some of those are hygroscopic and could degrade in high humidity. Maybe someone else has experience with this?Separate liquid or paste fluxes also last forever, well beyond their expiration dates.What doesn't last forever is solder paste: since it's solder powder suspended in paste flux, the huge surface area of all those microscopic solder powder balls reacts with the flux and corrodes. Additionally, the flux itself can degrade (including by evaporation). All of this means that old paste won't stencil as cleanly, and even if it does, it won't perform as well as fresh paste. So while it's OK to buy solder wire in large packages that will last you for years, only buy as much paste as you can use in a year or two. And keep it in the fridge.

author: lfldp
author_rank: Regular Contributor
timestamp: July 03, 2023, 07:21:10 pm
content: Quote from: tooki on July 02, 2023, 06:58:24 pmQuotethe one with 3,5% flux iso core "clear"Quotethats good information