Please recommend a good quality flux and solder - Page 1
Forum section: electronics / beginners

author: castingflame
author_rank: Regular Contributor
timestamp: July 24, 2020, 07:53:58 am
content: 1) While I have several cheap tin/lead leaded solder and lead free solder I am looking for some good quality replacements.2) More importantly, I am looking for a better flux that the ones I currently use.My current flux optionsThe bottled FluxThe flux in the bottle is very good but it leaves a very stick mess behind it. Obviously this can be cleaned with alcohol but it makes the process longer an messy and not very practical when doing a lot of joints. I would prefer a flux that I could use that is easier and leaves not residue.The Pen fluxThe pen flux is the other end of the scale as it leaves little residue but does not do such a good job.I guess I am looking for something in between of great quality!So please feel free to recommend some decent leaded solder, Lead free solder, Flux.Cheers

author: wraper
author_rank: Unknown
timestamp: July 24, 2020, 08:05:36 am
content: You could use LP-1 from the same manufacturer if you want a flux which does not leave much residues. TK-83 has very high rosin content and any such flux will leave a lot of residues.

author: Ian.M
author_rank: Super Contributor
timestamp: July 24, 2020, 11:00:57 am
content: You are probably over-applying the TK83 flux. Used sparingly, most liquid RMA fluxes can be treated as no-clean. Try diluting a small quantity with four parts of dry IPA*, to reduce its solids concentration to about 5%, then apply it sparingly with a lightly wetted Q-tip. If it not active enough at 5%, dilute it less (or mix in a bit more TK83). Once you've figured out a workable dilution, you can get a cheap refillable paint pen suitable for solvent paints & inks, and fill it with your diluted TK83 to make your own flux pen.Worst case: you may need to heat the board with a hot air gun to about 120 deg C to drive off the solvent in the flux so the rosin residue sets hard and non-sticky.* i.e. >99% pure Isopropyl alcohol. Don't use drugstore 70% IPA solution or similar as its water content is likely to separate out after mixing forming an aqueous layer that may strip activators from the flux.

author: exe
author_rank: Unknown
timestamp: July 24, 2020, 11:33:22 am
content: Quote from: wraper on July 24, 2020, 08:05:36 amI'm not sure it is no-clean.I used to use tk83, and I liked it. Afaik, it's only sticky until it dries out. I think it's just a mix of rosin and alcohol, once alcohol is evaporated it becomes solid and inert.PS I now use Russian fluxes like FN-255 which claimed to be non-conductive and suitable for sensitive equipment (I don't have an electrometer to test the claim). It even provide a sort of test protocol how they verify flux performance, I haven't seen such claims from any other manufacturers. If interested in details and "datasheets", seehttps://www.eevblog.com/forum/buysellwanted/fs(nlams)-cyberflux-group-buy-(russian-fluxes-non-corrosive-non-conductive)/. I believe you can buy them from ebay, although they are now produced by multiple companies, and I'm not sure how good they are now. They are also sticky (unless they solidify after extended heating, which makes it painful to remove it), so, probably, not suitable for you.

author: wraper
author_rank: Unknown
timestamp: July 24, 2020, 01:47:50 pm
content: Quote from: exe on July 24, 2020, 11:33:22 amhttps://termopasty.pl/wp-content/uploads/2019/07/Topnik-LP1_EN.pdf

author: exe
author_rank: Unknown
timestamp: July 24, 2020, 05:30:32 pm
content: Ah, missed that part. I was scared away by "Solubility in water", and not sure how to interpret it. Can it absorb moisture?

author: tooki
author_rank: Super Contributor
timestamp: July 24, 2020, 07:33:24 pm
content: Quote from: castingflame on July 24, 2020, 07:53:58 amThis question gets asked every few months on average (sometimes just days apart) and the answers are always the same. If you spend a little time looking for those discussions, you’ll find all the info you ever dreamed of. (Try googling “site:eevblog.com solder recommendation” and the like, since the forum’s own search kinda sucks.)

author: exe
author_rank: Unknown
timestamp: July 24, 2020, 08:46:05 pm
content: I'd also say that fluxes are over-rated. I spent years finding the best non-conductive flux, but, frankly, it's not that important unless parts and wires are severely corroded. And if it's corroded, then it can be cleaned and tinned before soldering.

author: Ian.M
author_rank: Super Contributor
timestamp: July 24, 2020, 09:10:33 pm
content: Its not that fluxes are over-rated (though some seem to think they are capable of magic), its that most wire solder and all solder paste contains enough flux to do a good job in all but the most challenging circumstances, provided you don't 'cook' it off before making the joint.There's no need to flood the area round the joint with flux 'Louis Rossman' style. He does that because he is often working with badly corroded pads and leads, and, as he has an ultrasonic cleaning tank, and the boards must be fully cleaned anyway, excess flux is cheaper than the extra time it takes to use just enough flux at New York labour and overheads costs.

author: exe
author_rank: Unknown
timestamp: July 24, 2020, 09:26:39 pm
content: He also uses a conductive flux (amtech 559 or something) which I don't recommend.PS by "over-rated" I meant there is no need to look for the "best" flux. In my opinion there is no big difference between them unless the board and/or parts is a mess.

author: bdunham7
author_rank: Super Contributor
timestamp: July 24, 2020, 09:52:53 pm
content: Leaded solder: Kester 44 core 63/37 in 0.8mm, 0.5mm and 1.0mm, in that order.Flux: I likehttps://www.allelectronics.com/item/sp-802/rosin-soldering-flux/1.htmlfor those occasion I need extra flux. It's a paste, you can use a toothpick to put a tiny bit on and it stays until you melt it.ROHS solder: I have AIM 2.5 Glowcore 1.0mm that I can use for lead-free new work if needed. If you are reworking lead free and can't use leaded, then life is tough.And then maybe you want some silver solder fora hundred buckssixty bucks a roll or so:https://www.rshughes.com/p/Kester-44-Lead-Solder-Wire-1-Lb-0-031-In-Wire-Diameter-Sn-Pb-Ag-Compound-36-Lead-Content-24-7150-0027/24_7150_0027/

author: tooki
author_rank: Super Contributor
timestamp: July 24, 2020, 11:24:09 pm
content: Silver bearing solder doesn’t have to cost $100 a roll. Also, you posted the same link twice.

author: exe
author_rank: Unknown
timestamp: July 25, 2020, 10:46:15 am
content: My favorite solder wire is stannol HS10. It has rosin core. Not the best flux, but does the job. I also tried some non-rosin flux because I don't like rosin residue, but it got me severe headaches even after short exposure to fumes.

author: Unixon
author_rank: Frequent Contributor
timestamp: July 25, 2020, 11:15:02 am
content: Leaded solder: ASAHI with CF10/FC5005 flux 0.5/0.6/0.8mm for through-hole stuff + 0.25mm for small SMDs.Lead-free solder: FELDER Sn97/Cu3 or Sn95.5/Ag3.8/Cu0.7 (maybe not the best choice but not much worse than leaded ASAHI counterpart)Flux: difficult question, flux choice heavily depends on particular soldering process (leaded/lead-free solder, soldering iron/hot air/IR, wire/pin/pad material).Some fluxes may leave residue that's difficult to remove if soldered with hot air/IR, but perfectly safe for use with soldering iron,other fluxes may colorize the solder mask on PCB at certain temperatures and can't be used with lead-free solder, but may be OK for leaded solder,some fluxes are active enough may damage gold pad finish and this depends on the temperature.

author: wraper
author_rank: Unknown
timestamp: July 25, 2020, 07:54:35 pm
content: Quote from: Unixon on July 25, 2020, 11:15:02 amReally? It's a high temperature solder, not something you should normally use for electronics.

author: Unixon
author_rank: Frequent Contributor
timestamp: July 25, 2020, 09:14:32 pm
content: Quote from: wraper on July 25, 2020, 07:54:35 pmAlmost all lead-free solder is high temperature, and as I said, these two I've listed may be not the best choice.I've seen leaded solder that is much worse at typical lead-free solder temperatures than these two alloys.Can't say it's really good for soldering semiconductors, but it works well for passives and mechanical components, at least it is not bad - flows well, has enough flux, makes clean joints, doesn't drag after iron. I don't use lead-free as much as leaded solder, so maybe I'm wrong on some account.p.s. Once I had a very funny Chinese leaded solder which loved to be stuck to soldering iron so much that it barely left any footprint on components except for a tiny film, at any temperature. The only thing it was good at is desoldering, because putting it on board and components was nearly impossible - all of it remained on the soldering iron tip.

author: wraper
author_rank: Unknown
timestamp: July 26, 2020, 12:30:24 am
content: Quote from: Unixon on July 25, 2020, 09:14:32 pmThen this is a very high temperature stuff if you call regular lead free high temperature. If talking about SnCu alloys, for electronics SN99.3Cu07 and Sn99Cu1 are used. Sn97Cu3 is more suitable for soldering pipes rather than electronics.EDIT:https://www.felder.de/products/copper-pipes-sanitary-installations/soft-solders-drinking-water-heating/fittingslot-cu-rotin-3-149727201.htmlQuote

author: Peabody
author_rank: Super Contributor
timestamp: July 26, 2020, 01:38:47 am
content: Can I ask about Radio Shack solder? I used it for decades, and am about to run out. Specifically this one in the 0.032":https://www.radioshack.com/collections/solder/products/snpb-60-40-rosin-core-solder?variant=31204770021446I never really paid any attention to the specifics before, but notice that it has an RA flux, which I understand is more aggressive than something like Kester 44, which is RMA, and in theory needs to be cleaned off afterwards whereas 44 doesn't. I've never really bothered with doing that, and don't recall having any problems.Anyway, this is even the right amount to last me for several years, so I thought I would order it. Is this not a good choice because of the RA flux? Does anyone else like this solder?

author: james_s
author_rank: Super Contributor
timestamp: July 26, 2020, 02:19:17 am
content: Any name brand 60/40 solder ought to be fine, some prefer 63/37 but after using some for a while I'm not real fond of it. The biggest difference is the flux, I have two different types of Amtech paste fluxes, RMA-223-TPF and 4300/LF. One is a rosin flux and the other is water soluable which I use with some solder that contains a similar flux. I like the water soluble stuff because it cleans up so easy however you HAVE to clean it up so I only use it when I can wash the thing I'm soldering. I don't use extra flux all the time but it really does make hand soldering SMD stuff easier as I can just use the solder that's carried on the tip of the iron. It's also helpful for soldering things that are a bit corroded.

author: Unixon
author_rank: Frequent Contributor
timestamp: July 26, 2020, 05:58:09 am
content: Quote from: wraper on July 26, 2020, 12:30:24 amWell, maybe...According to FELDER catalog, Sn97/Cu3 melts at 230-250C (top of the range) and Sn95.5/Ag3.8/Cu0.7 melts at 217C (bottom of the range), other alloys are between these two.To melt this 230-250С stuff one would need 300C+ on the tip so ... yes, only for passives and connectors.

author: exe
author_rank: Unknown
timestamp: July 26, 2020, 08:31:50 am
content: Quote from: Unixon on July 26, 2020, 05:58:09 amUhm, isn't 300C+ a normal temperature for the tip, is it? I solder at 320-330C, I've seen other people use as high as 360C (motivation: get the job quicker to reduce exposure to heat).PS Sometimes I go over 400C when reworking heavy connectors on ground planes...

author: m3vuv
author_rank: Super Contributor
timestamp: July 26, 2020, 08:47:49 am
content: ive brought a few reels of supposed 60/40 leaded solder from uk ebay sellers,when it is delivered,says made in china on the reel,turns out its lead free rubbish,just sommat to look out for,had one guy wanted me to send him pics of the crappy looking joints,my reply was dont you know what a dry joint looks like?,in the end i got %50 of my money back,not the ideal solution tho!!.

author: Unixon
author_rank: Frequent Contributor
timestamp: July 26, 2020, 09:10:51 am
content: Quote from: exe on July 26, 2020, 08:31:50 amThat depends on what you're soldering. For refreshing thermal pads on ICs and preparing DFN/QFN packages I go down to 200-240C, for soldering semiconductors 260-270C, for soldering passives 280-320C depending on heatsinking properties of a board, for mechanical components 320-340C and if I want to go fast on them 360-400C.Once I had a bunch of BSS138 that would be dead on the spot if you touch them with a hot tip, I had to go with tip as cool as it can barely melt solder or switch to low temperature solder for them, otherwise they started to conduct through the closed channel and through the gate too.

author: exe
author_rank: Unknown
timestamp: July 26, 2020, 09:19:05 am
content: Quote from: Unixon on July 26, 2020, 09:10:51 amSounds like an esd-issue or a reliability problem. The datasheet says it can be soldered with 300C for 10s. I believe these ratings are conservative.I have a level shifter made of, afaik, bss138 (the boards was bought on aliexpress). I'll resolder it with 400C tonight to see if I can damage it...

author: Unixon
author_rank: Frequent Contributor
timestamp: July 26, 2020, 09:36:46 am
content: Quote from: exe on July 26, 2020, 09:19:05 amAt first, I also thought that it is an ESD problem. But if this was an ESD, those MOSFETs would be damaged at the same rate at low temperature too, and other similar MOSFETs would have same problems, but they were not and the same fault mode later confirmed with a different batch of parts in different setting.Later we dropped BSS138 completely for 2N7002K.

author: Ian.M
author_rank: Super Contributor
timestamp: July 26, 2020, 09:49:39 am
content: When the Weller TCP 'Magnastat' irons were king in the service and hand assembly trades, they were supplied as standard with the PTAA-7 bit which set the temperature to 700 deg F, (370 deg C). Although you could get bits with Curie point slugs in the range 600 deg F (315 deg C) to 900 deg F (480 deg C), with the exception of a chunky 5mm PTDD-8 800 deg F bit which was always handy to have for heavy terminals, the other temperature rating bits were pretty much special purpose only - 800 deg F and hotter bits were too much of a PITA to keep tinned for general purpose work unless you religiously switched the station off for even small pauses in your workflow, and 600 deg F bits didn't deliver enough heat for anything except the lightest of work with the normal SnPb alloys that were in common use in that era.Quote from: m3vuv on July 26, 2020, 08:47:49 amI personally find its nearly as easy to work with good quality SnAgCu solders as with traditional SnPb solder. Pb-free <> rubbish.Due to the relative market prices of Tin and Lead, its unlikely your crap solder was actually Pb-free. See my comments here:https://www.eevblog.com/forum/reviews/soldering-question-tinning-16-awg-wire/msg3143318/#msg3143318.If you can also measure the melting point, you can identify the alloy supplied with a fair degree of certainty.Quote from: Unixon on July 26, 2020, 09:36:46 amIt may have been a moisture problem - its *rare* to get popcorning when hand soldering (excluding refow), but with a high enough soldering temperature it can happen.

author: exe
author_rank: Unknown
timestamp: July 26, 2020, 09:51:33 am
content: Quote from: Unixon on July 26, 2020, 09:36:46 amHmm, the 2N7002K has esd protection on the gate, while bss138 doesn't... Anyway, I'm glad you resolved the issue.Now here is my attempt to kill bss138 (presumably, smd marking is J1 H) with soldering it at 400C:.I will not put spoilers, you have to watch it to see the result. And, of course, I don't want to say that soldering at 400C is good for your parts.

author: wraper
author_rank: Unknown
timestamp: July 26, 2020, 10:14:45 am
content: BTW Sn97Cu3 solder wire is almost guaranteed to come with some nasty corrosive and electrically conductive flux inside it. So your issue might be exactly that, not temperature.Quote from: Unixon on July 26, 2020, 09:10:51 am

author: Unixon
author_rank: Frequent Contributor
timestamp: July 26, 2020, 10:53:48 am
content: Quote from: Ian.M on July 26, 2020, 09:49:39 amWith tip temperature around 250-260C one could watch a gradual degradation of a MOSFET.You measure it first - Rgs is out of range (>40MOhm), you touch it once (very shortly) - Rgs drops to MOhms, you touch it twice - Rgs drops to tens of KOhms, you touch it again - Rgs drops to about 1K.

author: exe
author_rank: Unknown
timestamp: July 26, 2020, 11:11:20 am
content: Quote from: Unixon on July 26, 2020, 10:53:48 amDid you short the gate to source? If it is floating, it accumulates charge and measurements are completely screwed. I know that from experience

author: Unixon
author_rank: Frequent Contributor
timestamp: July 26, 2020, 11:18:28 am
content: Quote from: exe on July 26, 2020, 11:11:20 amYes, before measurement. You touch it with a soldering iron, after every touch both Rds(Vgs=0) and Rgs drop down, this thing is starting to conduct while being closed!Other MOSFETs similar to that BSS138 could be also damaged with high temperature but this degradation speed was outstanding.

author: tooki
author_rank: Super Contributor
timestamp: July 26, 2020, 11:23:10 am
content: Quote from: Unixon on July 25, 2020, 11:15:02 amAre you absolutely sure you mean Sn97Cu3? It’s much more likely you actually have the Sn99.3Cu0.7.Quote from: wraper on July 26, 2020, 12:30:24 am(That’s Sn97Ag3, btw, not the Sn97Cu3 being discussed.)Quote from: wraper on July 26, 2020, 10:14:45 amThe Felder catalog actually does list Sn97Cu3 in its rosin electronics solders (ROM1 and ROL1), see pp. 6-7 onhttps://www.felder.de/products.html?file=files/felder/content/Kataloge/Gesamtlieferprogramm_2012_EN-kl.pdfNot that it sounds like something I’dwantto use on a PCB, with that very high melting point!

author: tooki
author_rank: Super Contributor
timestamp: July 26, 2020, 11:32:43 am
content: Quote from: Peabody on July 26, 2020, 01:38:47 amThe old RA/RMA system of flux categorization doesn’t tell you as much as the newer IPC system. In that one, Kester 44 and the radio shack RA solder are both type “ROM1”.I still have a bit of that 60/40 Radio Shack solder left over from my childhood. Has to be 25-30 years old now. But I only use it for tinning, as I prefer using 63/37. (My daily driver solder at home is the Kester 44 63/37 in .031. But I may try the 245 no-clean next time, as I see on its datasheet that it has much better solder spread than the 44!)

author: wraper
author_rank: Unknown
timestamp: July 26, 2020, 11:51:14 am
content: Quote from: tooki on July 26, 2020, 11:23:10 amYeah, wrong link, was posting late at night. Nonetheless Sn97Cu3 usually is referred as "plumbing solder" or for soldering aluminium and steel. Here is a link for Sn97Cu3 which says exactly the same:https://www.felder.de/products/copper-pipes-sanitary-installations/soft-solders-drinking-water-heating/fittingslot-cu-rotin-3-149727201.html

author: tooki
author_rank: Super Contributor
timestamp: July 26, 2020, 12:19:23 pm
content: Quote from: wraper on July 26, 2020, 11:51:14 amThat’s the page for an Sn97Cu3 plumbing solder, so obviously it’s going to describe its use for plumbing. But I already gave you a link to the Felder catalog which lists several Sn97Cu3 electronics solders. It’s weird and I don’t know why anyone would choose it, but they have it. Here’s the product page for one of them:https://www.felder.de/products/electronic-applications/manual-soldering-mechanical-soldering/solder-wire/loetdraht-iso-core-el-20971040.html

author: Unixon
author_rank: Frequent Contributor
timestamp: July 26, 2020, 12:36:40 pm
content: Lead-free solder in question: (updated image)

author: tooki
author_rank: Super Contributor
timestamp: July 26, 2020, 12:45:50 pm
content: Quote from: Unixon on July 26, 2020, 12:36:40 pmNot that I would trust website pictures (as they often reuse images for similar products), but that clearly says Sn99.3CuNiGe, meaning it’s 99.3% tin, and the remaining 0.7% is a mix of copper, nickel, and germanium. (Of which copper is likely the vast majority.) So... not Sn97Cu3, just as I suspected.

author: Unixon
author_rank: Frequent Contributor
timestamp: July 26, 2020, 01:34:25 pm
content: Quote from: tooki on July 26, 2020, 12:45:50 pmSorry, these lazy suckers always put wrong pictures on products and I missed it. Replaced with real photo.

author: Unixon
author_rank: Frequent Contributor
timestamp: July 26, 2020, 01:52:10 pm
content: And for completeness of imagery, leaded solder in question: These are really good, maybe even best out there.

author: exe
author_rank: Unknown
timestamp: July 26, 2020, 06:15:30 pm
content: Quote from: Unixon on July 26, 2020, 11:18:28 amYeah, if it's that sensitive, I'd throw it awayDo you remember that poor mosfet from the last video? Look what I've done to it:https://youtu.be/g_-7pVNsHrU?t=60(500C is maximum temperature on my hotair station).

author: Unixon
author_rank: Frequent Contributor
timestamp: July 26, 2020, 07:07:27 pm
content: Quote from: exe on July 26, 2020, 06:15:30 pmI've used up all of that batch with special care during assemblyThey were very cheap and worked fine if not overheated.Maybe I still have few of them somewhere... but now these would be 8-10 yrs old not including prior shelf life.

author: wizard69
author_rank: Super Contributor
timestamp: July 28, 2020, 04:00:17 pm
content: This thread has been beaten to death but one thing that has not been addressed is that poor soldering isn't always a materials issue. That is the operator is an element in the process and there practice really does make perfect. Frankly it is a lot like being a weldor, give two people the same welder and materials, one will produce crap and the other art work. So practice and working with various supplies, to learn what they can do for you, can help build up the skill level.Here is the thing there is no one right solder and flux combo for every soldering need in electronics. I may like 60/40 rosin cored solder while somebody else might go to a different alloy. The problem is I know that this solder will not work in every soldering task I might run into. For example liquid fluxes in a flooded manner are at times the right solution. Sometimes turning up the temperature on the iron is the right solution.The point I'm trying to get at is that asking questions is good but sometime you best develop skills by experimenting in different situations. In the end even though soldering a 14 ga wire to a switch is the same thing in concept as soldering a SMT lead to a PCB, the techniques used are a bit different. As a tech it really pays to develop your soldering skills to support a variety of situations.

author: bdunham7
author_rank: Super Contributor
timestamp: July 28, 2020, 04:28:01 pm
content: Quote from: wizard69 on July 28, 2020, 04:00:17 pmPerhaps. But early on I always wondered why I could solder radiators and copper pipes so well but I just absolutely sucked at electrical soldering. Then, faced with the need to actually do a good job, I splurged and bought a pro-quality Antex temp-controlled iron and some $$$ silver-bearing rosin core solder from Radio Shack and all of the sudden I was a soldering pro. There's a certain level of quality for both equipment and solder that if you go below it there's nobody that can do a decent job. And there's plenty of that crap readily available in the market.

author: tooki
author_rank: Super Contributor
timestamp: July 28, 2020, 07:24:28 pm
content: FWIW, silver-bearing leaded solder is generally a bitharderto work with than 63/37, which is in many ways the optimal alloy for electronics, RoHS notwithstanding.

author: bdunham7
author_rank: Super Contributor
timestamp: July 28, 2020, 08:35:27 pm
content: Quote from: tooki on July 28, 2020, 07:24:28 pmThat's sorta part of the point. My skills weren't the problem, it was the crap I was trying to use because I didn't know how much better non-crap stuff was. The Radio Shack silver solder made magnificent solder connections and I still have some left 30 years later. I suspect the iron made more difference than anything else.

author: Unixon
author_rank: Frequent Contributor
timestamp: July 28, 2020, 10:15:09 pm
content: Quote from: wizard69 on July 28, 2020, 04:00:17 pmI'm afraid that if we start comparing our soldering skills in this thread this would turn out in a weird kind of dick measuring contest instead of initial request for good flux and solder.Despite of this I must say that I agree with your points and that skills do matter even with good materials.I know everyone have some tricks in their sleeves and I would encourage to open up another appropriately named thread and share that knowledge there.

author: Unixon
author_rank: Frequent Contributor
timestamp: July 28, 2020, 10:42:55 pm
content: Quote from: castingflame on July 24, 2020, 07:53:58 amWhere do you buy electronic stuff?

author: wizard69
author_rank: Super Contributor
timestamp: August 02, 2020, 02:03:08 am
content: Quote from: Unixon on July 28, 2020, 10:15:09 pmThe point of my post wasn't to start a contest it is just that if somebody is new starting out in this field they need to try different materials and techniques to see what works best in a specific situation. For example some will discount the value in separately applied fluxes but I've seen first hand how a good flux added to a difficult solder job makes a huge difference. Asking questions is good but you also have to take answers with a grain of salt and objectively test the suggestions.As to the other question you posted about buying electronic stuff there are lots of options. My answers would be more biased to industrial suppliers as that is what I've worked with over the years. In any event some suggestions:Keysight, we don't buy a lot of test equipment but they are the first choice for mainstream bench hardware.Fluke, for handheld meters.DigiKey, for what I call hard electronic components and materials. They also have a very good web site compared to many othersNewark, for things that might be seen as more industrial. They also have a terrible web site that drives me away.Simcona, Especially for cablingMcMaster-Carr, Actually the world biggest hardware store. One of the best business oriented web sites going but with one bad characteristic, they make it hard for the user to determine brand names / origins. Great place for hardware though.Mouser, honestly have not dealt with them much.Horizon, Industrial electronics and components.MSC, Largely a horribly expensive site for industrial machining tech but they do carry some electronic equipment. Their good point is an uncanny ability to get stuff to you fast.CS Automation, probably not stuff you want unless you are building a fancy home CNC system.techni-tool, Not a big customer anymore mostly due to not having technicians traveling all over the place.Brook Anco, mostly for optics in our case.DXP, mostly oriented to the machining industry.spectraservices, largely optics.Occasionally we have to trace down vendors for components that are not easy to fin in the USA. For example some PCB mounted push buttons for old FANUC controllers. This is the real trick to fixing things, that is tracing down hard to find components, it is a skill all on its own. So there have been a lot of one time vendors, where we buy a transistor or whatever and might not see that supplier ever again.

author: Teledog
author_rank: Regular Contributor
timestamp: August 08, 2020, 07:07:42 pm
content: Whatever you use, just make sure it's big!Was given this chunk of solder many years ago by a retired hydro generator rewinder (he's passed on now).They supposedly used massive wooden sledge hammers to pound in the windings/bars back in the day.Flux?..no idea what they used back then.. perhaps pine saplings? ;-)

author: castingflame
author_rank: Regular Contributor
timestamp: August 09, 2020, 04:31:54 am
content: Thank you all for your answers.The main reason for flux for me is if I want minimal heat build up on a part, to re-flow a joint but Mainly for removing bridged connections on high density SMD parts after being in the oven. I have found solder wick dipped in a flux removes the bridges much much quicker in one go in a very much neater way.I will take your comments on board and make some choices next time I make a decent order.

author: ercapoccia
author_rank: Regular Contributor
timestamp: August 09, 2020, 08:23:50 am
content: For through-hole components i use Topnik Rf800 and amtech 599-v2-tf for smd. Multicore leaded 63/37 for everything, it is excellent and it is not too expensive.

author: Unixon
author_rank: Frequent Contributor
timestamp: August 09, 2020, 12:26:13 pm
content: Quote from: castingflame on August 09, 2020, 04:31:54 amIf you have a real sensitive part or consider swapping it in the short run you can use low melting temperature alloy (e.g.https://en.wikipedia.org/wiki/Fusible_alloy), or mix yourself an allow for a specific temperature. A 50/50 mix by weight of Rose's metal with 60/40 leaded gives you an allow that melts at ~150C, which is pretty nice thing to have. This is very useful if you want to desolder a component without heating everything around it to a high temperature: you either solder it initially with low temperature solder or you put low temperature solder on the component to dissolve high temperature solder that is already there.

author: lfldp
author_rank: Regular Contributor
timestamp: November 27, 2021, 09:00:30 pm
content: Quote from: castingflame on July 24, 2020, 07:53:58 amhithe best flux for lead free which i use from long time is SYNTECH-LF-TF genuine from amtech company , is goog for smd solder also reballing and is almost heavy-odour less because is syntetic , amtech have also lf-4300 for lead-free/leadded solder and NC-560 for lead free , but from my opinion and experiments i can say i cannot solder correctly all lead-free balls on large bga this water washable flux almost evaporate untill every ball flow to pad position , as about NC-560-LF i cannot completly solder lead-free ballsSYNTECH-LF-TF - works very good with lead-free solder and did not evaporate untill bga balls flow to its position , heavy odour-less nice smell because is synteticthis flux is also manufactured by CHIPQUIK company and is only usefull for lead-free solderLF-4300 water washable flux also almost odourless but it is usefull from my opinion only for leadded solder with lead-free it too fast evaporateNC-560-LF - no good for bga maybe for smd ive never place any balls on cpu correctly - it is irritant when inhalle !!!from my opinion for lead free solder you need flux which will keept you temperature more longer than usuall flux for sn60/40 leadded , it should be dedicated for lead-free solder only like syntech-lf-tf

author: jmelson
author_rank: Super Contributor
timestamp: November 28, 2021, 11:22:36 pm
content: I have used MG Chemicals "Rosin Flux" Catalog # 835-100ml, which works very well, but leaves a sticky mess. If I want it to be cleanable, I use SRA No. 80 Water soluble refill for flux pen, which works quite well, and can be washed off in seconds with running water.Jon

author: lfldp
author_rank: Regular Contributor
timestamp: July 27, 2022, 03:40:09 pm
content: hello i have question maybe someone knows...which from chinese flux is suitable for lead-free alloys ? because as i see there is no rule in china market about leadded alloy or lead free as in case of valid fluxi did tryin several chinese flux like rma-218 amtech nc-559-tpf(uv) rma223 also rma223uv and uv559 and i can say only rma-218 and uv559 hitting lead-free alloys the nc-559-tpf(uv) completly doesnt works on lead-freethe uv559 mechanic flux is more better than rma-218 for lead-free but this is not exactly what i need eg. previously using original amtech flux type syntech-lf and this flux is keeping more longer temperature on lead-free alloys than chinese uv559 do anyone knows lead-free chinese flux comparable to amtech syntech-lf ? been tryin also original amtech nc-560-lf but this flux dont keept so long enough temperature like syntech anyways chinese uv559 in this case is more better than original nc-560-lf

author: lfldp
author_rank: Regular Contributor
timestamp: July 27, 2022, 05:22:05 pm
content: future candidates for my tests and experiments with lead-free are:mechanic flux MECHANIC F913 F933 Mild Rosin also improved version of uv559 flux called CMOV-559TC-HE - this is not nc-559-tpf(uv) coz this version is made from completly different materials and like i wrote before is completly uselless for lead-free

author: wraper
author_rank: Unknown
timestamp: July 27, 2022, 06:41:14 pm
content: When you buy fake Chinese "Amtech" flux, nobody can tell how it will perform because there are many different fake fluxes sold under a single amtech model. So may be from OK-ish to unusable garbage. Even effing Kingbo is almost impossible to buy not couterfeit, even though even real Kingbo is deceitful by pretending to be Japanese.

author: lfldp
author_rank: Regular Contributor
timestamp: July 28, 2022, 11:23:42 am
content: ehh i have allways same flux buying it from same officiall mechanic shop in china but they released two new models thats why im asked which one could be good for lead-free , anyways is much more better choice than buying syntech-lf directly from usa + paying twice time more for its price also for shipping and waiting over 50 days till it arrive to my countryafter covid attack any of original amtech isnt available anymore in my country

author: wraper
author_rank: Unknown
timestamp: July 28, 2022, 12:37:48 pm
content: Quote from: lfldp on July 28, 2022, 11:23:42 amTry this flux from Alphahttps://www.tme.eu/pl/en/details/topnik-gel-bga/fluxes/alpha/om-338/and don't bother with Chinese junk. A very good flux, the only downside is that its fumes are a bit nasty, therefore good ventilation recommended. IMHO Amtech fluxes are not that special or exceptionally good to begin with.

author: lfldp
author_rank: Regular Contributor
timestamp: July 28, 2022, 03:57:04 pm
content: Quote from: wraper on July 28, 2022, 12:37:48 pmok but this flux is good for lead-free ? i mean does it keept temperature long enough on lead-free solder ? btw. about fumes i completly dont care i have chinese fume extractor and it does it job well

author: wraper
author_rank: Unknown
timestamp: July 28, 2022, 05:16:49 pm
content: Quote from: lfldp on July 28, 2022, 03:57:04 pmYes. This flux has especially long working time.