Which Kester solder to buy? - Page 1
Forum section: electronics / beginners

author: Curious2know
author_rank: Contributor
timestamp: September 28, 2018, 07:12:51 pm
content: Hi,so I need some new solder and I can get good prices on Kester solder. I'm just wondering what type should I buy? So in order of acitivity there would be 44 - 285 - 245. One interesting thing I saw in the datasheets is that 44 has the lowest wetting capability by the spread test. Also it scored "moderate" on the corrosion test. How does that make sense? Why would anyone buy 44 anymore if 245 does all of that but better?Regards

author: helius
author_rank: Super Contributor
timestamp: September 28, 2018, 07:40:51 pm
content: Kester 44 is the industry standard for activated rosin flux, and contains more activators than an RMA flux such as 285. This means that residues can be more corrosive under some circumstances, but it is not a problem if the board is cleaned.Kester 245 is a low-solids no clean flux, which is typically used by spraying for wave soldering (or selective soldering) machines. This type of flux can be a problem for manual soldering since it has less activators and is more liable to running out of the solder wire before being used (due to the low solid content). I wouldn't recommend it at all for this purpose.

author: Curious2know
author_rank: Contributor
timestamp: September 28, 2018, 07:45:15 pm
content: So it's basically 44 vs 285 depending on if I work on new or older stuff mostly?

author: FotatoPotato
author_rank: Regular Contributor
timestamp: September 29, 2018, 12:29:44 am
content: I think I'm one the only people on earth who have ever had a bad experience with kester solder; My $60 reel came all tangled and ruined and I had to cut off nearly half of the solder to get to anything usable that could be unspooled properly. After that I tried some Multi-core sutff and it was/ is fantastic! I would highly recommend it. But if you are going to get some kester solder, I would get some 0.025in 63/37 solder. The usable part of my spool seems to work quite well for smd soldering.

author: David Hess
author_rank: Super Contributor
timestamp: September 29, 2018, 03:14:34 am
content: Quote from: Curious2know on September 28, 2018, 07:45:15 pmThat basically is it. Use 44 for rework and if the boards and parts are not new. Use 285 with new parts and boards.

author: Curious2know
author_rank: Contributor
timestamp: September 29, 2018, 08:44:08 am
content: Thanks everyone!

author: tooki
author_rank: Super Contributor
timestamp: September 29, 2018, 12:50:08 pm
content: Quote from: FotatoPotato on September 29, 2018, 12:29:44 amSo you had a bad experience with solder getting tangled, and it happened to be with Kester. I don’t think solder quality affects the tangle-resistance in any way!As for having to cut it: you do realize that using cut lengths of solder is actuallypreferableto using it straight off the spool, right? The cut ends allow flux to flow sooner than with melted-off ends, which are a gamble as to whether the flux core remains exposed, or sealed inside a droplet of solder.

author: guymo
author_rank: Regular Contributor
timestamp: September 29, 2018, 06:16:44 pm
content: Over on the synth-builders forums I frequent the recommendations are always 331 for washable parts and 245 for the remainder. I’m very interested to hear that 245 is not ideal for hand soldering. Hmmm...(I’ve always used multicore to date, no issues, but was wondering about trying out some Kester)

author: 6PTsocket
author_rank: Regular Contributor
timestamp: September 30, 2018, 02:03:09 am
content: Another vote for Multicore.If I ever use it up I will try 63/37. Having no "mushy" state and going directly from liquid to a solid is an improvement over 60/40. I know if no down side.Sent from my SM-G900V using Tapatalk

author: james_s
author_rank: Super Contributor
timestamp: September 30, 2018, 06:38:49 pm
content: Quote from: FotatoPotato on September 29, 2018, 12:29:44 amI'm not going to argue which brand of solder is superior because I suspect both are good products, but this sounds like a problem with the vendor rather than the manufacture. Sounds to me like the product was damaged in storage or transit rather than being manufactured defective.

author: David Hess
author_rank: Super Contributor
timestamp: September 30, 2018, 07:33:37 pm
content: Quote from: 6PTsocket on September 30, 2018, 02:03:09 amI have never noticed any difference in usability or performance between 63/37 and 60/40 but I assume it is there. I prefer 63/37 though.

author: james_s
author_rank: Super Contributor
timestamp: October 01, 2018, 01:44:39 am
content: I recently got some 63/37 when I finally used up the roll of 60/40 I had. It does seem to firm up just a tad faster but that could be in my imagination. The flux is certainly nicer in this stuff though, my last roll was some kind of no-clean rosin flux that when I did want to clean it off, made a big sticky mess. The flux in this new solder washes right off with flux remover providing a much nicer experience.

author: FotatoPotato
author_rank: Regular Contributor
timestamp: October 01, 2018, 05:17:06 pm
content: Quote from: james_s on September 30, 2018, 06:38:49 pmI agree, It was probably thrown around during shipping, The part that I could use has worked very well but i personally just prefer the Multi-core brand not that its any better or worse than the Kester stuff. They are both excellent.

author: David Hess
author_rank: Super Contributor
timestamp: October 03, 2018, 02:47:51 pm
content: If your solder is old, then wiping off the tarnish on the outside will result in cleaner joints.

author: GreyWoolfe
author_rank: Unknown
timestamp: October 04, 2018, 12:21:10 am
content: I use Kester 44 63/37 for all my soldering needs, new or old. No issues. YMMV.

author: aabbcc
author_rank: Regular Contributor
timestamp: October 05, 2018, 12:34:37 pm
content: Quote from: guymo on September 29, 2018, 06:16:44 pmI recently switched over to kester 331 63/37 and I love it, the boards gets super clean with simply some tap and di water. My ocd can't handle flux residue and spatter all over the place so this stuff is a life saver, no more trying to scrub of no-clean flux with heaps of ipa.Use multicore 60/40 crystal 502 since I have a huge roll for mechanical and non-washable parts.

author: macboy
author_rank: Super Contributor
timestamp: October 05, 2018, 01:18:56 pm
content: Quote from: aabbcc on October 05, 2018, 12:34:37 pmThere's your problem... "no clean" flux is not meant to be cleaned, and certainly not with IPA. If it really needs to be cleaned you need a Kester-specified saponifier or cleaning agent, and you need to clean extremely well or you just spread the residue all over board. IPA will not do the job and will leave all sorts of nasty residue.Most any Rosin-based flux will clean quite nicely with IPA. It's a little trickier if it burns/chars but it is still quite easy. If the IPA istoopure (there is such a thing) then you might need to add just a little water to the initial scrub to help dissolve stuff that IPA itself can't do. Final rinse with the purest IPA you have will help remove almost all traces of water.You will find that Kester 44 (RA) or 285 (RMA) clean up easily and solder well. And they smell not too bad as well, certainly better than most no-clean or water soluble fluxes.I have some Alpha Cleanline 7000, which has some kind of mystical unicorn "no clean water soluble" flux. Apparently perfectly safe to leave on the board, but also easily cleaned with water. I don't use it because it smells nasty, which is probably due to all the active parts of the flux being designed to vaporize during soldering, which is how they achieve the no-clean part.My recommendation is Kester 44in either 63/37 or if you can afford it 62/36/2 (2% silver). The silver bearing solder is worth it, it melts at a lower temperature and the joints will be smoother and shinier than any you've ever made. It's also stronger, and it won't leach silver away from silver-plated parts. The 44 flux is the best I've ever used, making solder flow like melted butter, and it tackles tough oxidized stuff where lesser fluxes fail. It cleans easily with IPA but can be left behind if you don't care about looks.

author: jeffreyjames44
author_rank: Contributor
timestamp: October 05, 2018, 04:22:13 pm
content: Kester 44 is the go to

author: David Hess
author_rank: Super Contributor
timestamp: October 07, 2018, 03:55:53 am
content: Quote from: macboy on October 05, 2018, 01:18:56 pmSn62Pb36Ag2 is the strongest of the low temperature SnPb solders and I do like it however I have always had trouble getting joints which look as good as Sn63Pb37 or Sn60Pb40.Interestingly enough, I can smell the difference between Sn62Pb36Ag2 and Sn63Pb37 or Sn60Pb40 when soldering. Maybe they use a different flux?I think Tektronix used a solder with a higher silver content then 2% on their early oscilloscopes which used fired silver on ceramic terminals.Update: apparently Tektronix used a 3% silver solder but I do not know any more details about it.

author: exe
author_rank: Unknown
timestamp: October 07, 2018, 11:16:06 am
content: Quote from: macboy on October 05, 2018, 01:18:56 pmI think the name is very misleading. It's "no-clean" only under certain conditions. A partially activated flux is not "no-clean", it will conduct and it will cause corrosion. That's definitely the case when doing hand-soldering when there is any sort of "thermal profile".So, I suggest clean the flux unless flux was tested to be non-conductive non-corrosive in both cold state and after heating.I have like 10-15 fluxes, most of them "no-clean", and I can definitely state only few of them are really unconditionally safe to use.

author: aabbcc
author_rank: Regular Contributor
timestamp: October 08, 2018, 09:39:32 am
content: Quote from: macboy on October 05, 2018, 01:18:56 pmYes I'm aware of that, all though the IPA cleansing worked perfectly fine since I always used IPA+kimwipes to get rid of all the residue.However it takes alot longer then simply rinsing it with water hence the change to Kester 331, I'd rather use a solder which I can clean up the flux with water/di-water without having to buy an additional chemical just for cleaning.