Kester 331 faulty? - Page 1
Forum section: electronics / beginners

author: Harrysteed
author_rank: Newbie
timestamp: October 26, 2023, 08:12:59 am
content: Hello everyone, I'm new!I did some DIY and ended up enjoying electronic assembly on new PCB's.I heard a lot about Kester 331 solder so I got myself a new old stock Kester part number 24-6337-6416.Usually I work with the Weller WSW SN40PB L1.Kester 331, I have a really hard time melting it without the temperature leaving a gaseous brown color on the soldering iron.(heat). It dates from March 23, 2001. Is it possible that he lost his properties?

author: RayRay
author_rank: Frequent Contributor
timestamp: October 26, 2023, 09:30:59 am
content: It's fake:https://www.kester.com/products/product/331-flux-cored-wireAs you can see on their site, 24-6337-6416 is not listed, only other number that is somewhat similar is 9263376416, but 92 isn't 24 clearly.My advice, get one of these solders, I can vouch for em being high quality:Mechanic HX-T100 63/37https://www.aliexpress.com/item/1005004692039059.htmlBest 60/40https://www.aliexpress.com/item/1005005490425084.html0.5 & 1.0MM are good for general soldering work, 0.3 for SMD stuff.

author: Harrysteed
author_rank: Newbie
timestamp: October 26, 2023, 01:15:08 pm
content: Hello, I bought this one to be able to clean my PCBs, it comes from an old stock! Before ordering anything, I need to know if there is a problem

author: RayRay
author_rank: Frequent Contributor
timestamp: October 26, 2023, 05:13:15 pm
content: Quote from: Harrysteed on October 26, 2023, 01:15:08 pmThere has to be something lost in translation here! Solder is not made for cleaning PCBs...Regardless, I've already given you a solid answer. It's more than likely fake (as the specific part number isn't listed on Kester's website) as I've already showed you before. If you choose to believe otherwise, that's on you. Now, regardless, the PDF (datasheet) lists the shelf life of this solder as 3 years:https://www.kester.com/DesktopModules/Bring2mind/DMX/API/Entries/Download?Command=Core_Download&EntryId=1051&language=en-US&PortalId=0&TabId=96And it also states the following: "The 331 flux residue is conductive and will cause corrosion of metal parts over time. Residueremoval should be completed within 48 hours" Meaning the flux used on it is conductive (which makes it a very poor choice for electronics work, as you could easily cause a short/fry components if you don't do a proper cleanup afterward!) anyhow, solder is the last thing you should buy as "new old stock" and it is what it is, whether it's fake or not (and again, I believe that is) it's unusable, so you're gonna have to get rid of it and get something else.

author: Harrysteed
author_rank: Newbie
timestamp: October 26, 2023, 05:40:53 pm
content: Indeed, I expressed myself badly! I plan to clean it in less than 48 hours after welding. Either way, there must be something wrong with this product at the time of the merger.I will settle for the Weller which is comparable to the Mechanic or even better, however, I will have to go behind each solder to clean the excess flux with the IPA

author: tooki
author_rank: Super Contributor
timestamp: October 26, 2023, 09:32:43 pm
content: Quote from: RayRay on October 26, 2023, 09:30:59 amIt’s not fake. It’s just a discontinued package size. (Or a size custom-made for some large customer.) The first two numbers of a Kester SKU is the size of the roll. 24- is a 1lb (454g) roll, 92- is a 500g roll. They’re probably just transitioning everything to metric little by little.Quote from: RayRay on October 26, 2023, 05:13:15 pmNOS solder is fine if it’s rosin or resin flux. With organic, I’d be leery since it’s hygroscopic and could theoretically degrade in humidity.This solder isn’t categorically a “very poor choice for electronics work” — it’s soldermade for electronics. With that said, being organic acid, it MUST be cleaned flawlessly, lest corrosion occurs. This means you absolutely cannot use it, for example, to tin stranded wire, since flux will wick into the wire, and cleaning with water will only wick it in deeper.I’d be wary of using water soluble solder even for its intended purpose of washable PCBs unless I had a proper heated ultrasonic cleaner or board washer. (Since I don’t, I stick with rosin/resin and no-clean flux.)

author: tooki
author_rank: Super Contributor
timestamp: October 26, 2023, 09:56:27 pm
content: Quote from: Harrysteed on October 26, 2023, 08:12:59 amTwo potential issues, having never used that solder myself:1. Maybe it always causes residues on the iron. Does it work fine otherwise?2. It could have gone bad. Water washable flux is hygroscopic and so will absorb water from the air, and it’s entirely plausible for it to have reacted with the water in the 22 years it’s been in storage. I would expect that it’d be worse at the ends, so you could try cutting off the first few meters and seeing how some of it from “deeper” in the roll behaves.Note that Kester always says 3 years shelf life on their solder, even the rosin ones that stay good basically forever. This is likely legal “cover your ass” protection.Quote from: Harrysteed on October 26, 2023, 05:40:53 pmI assume you’re using machine translation, but I’ll say anyway: not welding. Soldering. They’re entirely different processes.I have no idea what you mean about the “merger”.Quote from: Harrysteed on October 26, 2023, 05:40:53 pmI would avoid the Mechanic product precisely because thatisa brand that is widely counterfeited (which is not the case with Kester!).Kester is a fantastic brand (it’s my preferred brand), but 331 isn’t what I would recommend, since (as I explain above) it CANNOT be used as an all-purpose solder.Kester 44 is basically the gold standard in rosin flux, and you will have great results with it. Kester 285 (which I’ve never used) is supposedly excellent if you’re using new boards and parts without much oxidation. Both of them are safe to leave on the board without cleaning.

author: RayRay
author_rank: Frequent Contributor
timestamp: October 26, 2023, 10:38:50 pm
content: tooki - you seem to have a habit of always going against what I say.Whether it's fake or not (which if being fair, none of us can say for 100%) I still stand by my conclusion due to the reason I've already stated. Regardless, it seems to be unusable, and even if it was, how can you possibly say that solder that uses flux that is both conductive & corrosive is good for electronics? I'd personally steer clear from such. Anyhow, I'm pretty sure the Mechanic solder I linked to is original, and I've never heard of their leaded solder being faked, only their lead-free (Sn42Bi58 one). And as for Kester solder as a whole, it's not the only manufacturer of high quality solder, and you can only get it at fair pricing in the US, outside of it, you'd get ripped off and it won't be cost-effective.

author: Jwillis
author_rank: Super Contributor
timestamp: October 27, 2023, 03:16:01 am
content: Quote from: Harrysteed on October 26, 2023, 08:12:59 amAs it has been stated before , that particular catalogue number no longer exists. Depending on how long it has been discontinued , as tooki mentions, the flux has probably gone bad. "New old stock" is a pretty good indication of obsolescence. Have you tried adding fresh flux while soldering? If it starts to flow better and the joint looks better with added fresh flux, that would indicate that the solder is just old.

author: tooki
author_rank: Super Contributor
timestamp: October 27, 2023, 09:59:17 am
content: Quote from: RayRay on October 26, 2023, 10:38:50 pmI’ve only ever responded to you in two threads, this one and one other. That doesn’t constitute a “habit”.Quote from: RayRay on October 26, 2023, 10:38:50 pmCorrect, neither of us can be 100% certain. But NOS on eBay from Poland (the only place that seems to have it) is certainly more likely to be genuine than stuff on AliExpress, where nearly any name-brand product is likely to be counterfeit!!Quote from: RayRay on October 26, 2023, 10:38:50 pmBecause, as I have already stated, it is literally made and sold for electronics use. The flyer for it lists typical electronics applications. The datasheet shows theelectronics industrystandards it complies with. The listed compatible liquid flux describes explicitly that it’s designed for printed circuit boards.As I also already have stated, I also do not recommend such fluxes for most users because of the strict requirements for their use: nothing where it can wick, and only where heated ultrasonic or high pressure washing can be performed.Water soluble fluxes are quite common in mass production of circuit boards, where the fluxing and washing processes can be very carefully controlled. They are not suitable for every board, which is why no-clean fluxes and fluxes that require solvent cleaning exist.Quote from: RayRay on October 26, 2023, 10:38:50 pmOn AliExpress, almost everything name-brand is fake. Mechanic brand bought from a proper distributor is certainly fine, but come on, man, AliExpress?!?Quote from: RayRay on October 26, 2023, 10:38:50 pmWhere did you see me say it’s the only manufacturer of high quality solder? Again, nowhere, because I didn’t say that. Stop putting words in my mouth.I (and many others) have found Kester 44 to be the nicest solder to work with, bar none.But there are indeed numerous good brands. MG Chemicals, Almit, AIM, Indium, Felder, and Tamura-Elsold, to name a few. The only popular name brand solder I dislike is Stannol, which I find to spit a bit more than most, and whose lead-free doesn’t flow as well as other brands (like Felder, currently the best lead-free I’ve tried, though I haven’t yet ordered any Kester lead-free.)Kester solder is easily shipped to most of the world by digikey and mouser. But yeah, it’s not the cheapest. (Nor the most expensive.) I always maintain that the cost of solder wire is ultimately trivial: you use so little of it per joint that the cost is simply irrelevant until you’re at large-scale production. Whether a spool costs $30 (like your aliexpress Mechanic solder) or $60 like a spool of Kester makes no difference given that a spool will last me many years. So I choose to go with the “premium” option simply to eliminate the risk of poor solder ruining a project, or even just being slightly more annoying to use. And that’s what I recommend to others, too. (Buying solder paste is a much more complex affair, in that its very limited shelf life means that you need to buy in small containers that you can finish before it goes bad. Unfortunately, many solder pastes, including the GC 10 that many consider to be the very best on the market, are only sold in industrial size containers.)

author: RayRay
author_rank: Frequent Contributor
timestamp: October 27, 2023, 12:18:39 pm
content: Quote from: tooki on October 27, 2023, 09:59:17 amThat's your personal opinion and not factual information, and I've ordered Mechanic branded solder from AE multiple times and never had a problem. Aliexpress is just a platform that allows different sellers to sell their stuff, it works similarly to ebay/amazon, except that it caters exclusively to Chinese sellers.Quote from: tooki on October 27, 2023, 09:59:17 amDude, this is getting embrassing! You really need to work on your reading comprehension skills.At no point did I stated that you've said the above.

author: tooki
author_rank: Super Contributor
timestamp: October 27, 2023, 08:19:33 pm
content: Quote from: RayRay on October 27, 2023, 12:18:39 pmI know how aliexpress works. The fact remains that it’s well-known that it’s chock-full of counterfeit goods. The fact that your fluxworksis no guarantee that it’s genuine. Regardless, my point is that it’s mind boggling that you’d instantly cry “It’s a faaaake!” just because of an obsolete part number, yet give aliexpress, of all things, the benefit of the doubt!Quote from: RayRay on October 27, 2023, 12:18:39 pmWell when you word your statement in a confrontational kind of way, as you did, you’re at the very least implying it.At least I tried veering the discussion back to providing useful information, unlike your insistence on responding only to your imagined slights. (You seem to think I have it out for you. Honestly, had you not said anything, I wouldn’t have even realized I’d ever responded to you in any other thread. You don’t occupy any of my headspace. I responded solely to the content of the posts, nothing more.)

author: Harrysteed
author_rank: Newbie
timestamp: October 30, 2023, 09:17:18 am
content: Quote from: RayRay on October 26, 2023, 05:13:15 pmFake? The photo seems pretty self-explanatory! Anyway, I started working with my usual Weller. Buy from Mouser. I'm moving forward with some IPA on hand and it seems to be working for me,

author: Harrysteed
author_rank: Newbie
timestamp: October 30, 2023, 09:24:03 am
content: Quote from: tooki on October 26, 2023, 09:56:27 pmHi Tooki, I naturally followed your advice regarding the conditions of use of Kester 331, I prefer to back away from the risk of corrosion. Washing requires some maneuvering. Thanks Valuable information.I will definitely get a Kester 44 for the pleasure of making my job easier in the near future because I have heard a lot of good things about it too