Organic-core solder? (Kester "331") - Page 1
Forum section: electronics / general

author: FenderBender
author_rank: Super Contributor
timestamp: November 29, 2012, 12:34:17 am
content: I'm doing a bit of a revamp in the soldering department in my lab.Right now I use a Weller WLC100, a cheap helping hands, and Kester "44" solder. It works okay. Bit of a nuisance.I've been searching around for solder. I came across Kester "331" which is basically an acid-core solder that is soluble in water, unlike rosin-core.Sounds good, but it seems a bit scary. Forget to clean off some residue and you're screwed (because it's conductive)!Has anyone used this type of solder before? What do you think?

author: IanB
author_rank: Super Contributor
timestamp: November 29, 2012, 01:15:39 am
content: What's wrong with Kester 44? It looks like an ideal solder for hand soldering.

author: FenderBender
author_rank: Super Contributor
timestamp: November 29, 2012, 01:25:59 am
content: Quote from: IanB on November 29, 2012, 01:15:39 amIt is very good solder. I will continue to use it. However, when I build a board from scratch or want to make the end result pretty, it's almost impossible to clean the residue off from the "44" stuff. The residue is pretty much non-corrosive but I want my final boards to be nice and clean. And easy to clean.

author: IanB
author_rank: Super Contributor
timestamp: November 29, 2012, 02:29:34 am
content: OK. Flux residue doesn't just rinse off. You need to use a soft bristle brush (a toothbrush?) and a suitable solvent such as alcohol or IPA.

author: FenderBender
author_rank: Super Contributor
timestamp: November 29, 2012, 02:46:30 am
content: Quote from: IanB on November 29, 2012, 02:29:34 amI'm well aware. I have tried using isopropyl alcohol and a tooth brush on the residue caused by the 44. And I always get a white film after it dries. (The cleaning spreads the residue more than cleaning it off and then it dries and hardens in places I don't want it...like the other side of the board which is tightly populated. Thus the other side is now "contaminated" and I can't really scrub it off because the parts are so close to each other.) Maybe I just don't know the right technique? I've been able to sucessfully remove the 44's residue when working on mainly SMD boards because I can just scrub right over all the SMT parts regardless of what side they are on. But through hole is another story.The "331" solderaccording to the datasheet, says that it comes off with water and some scrubbing.Just wondering if anyone has any used this stuff and if they can recommend it or not, before I go dump $25 on a 1lb spool.

author: RCMR
author_rank: Frequent Contributor
timestamp: November 29, 2012, 03:42:33 am
content: Acid core?Use it for your plumbing fixtures!Interestingly enough, I'm using some Chinese-made solder right now and it does a wonderful job with very little flux residue at all.I think I was just lucky

author: FenderBender
author_rank: Super Contributor
timestamp: November 29, 2012, 03:52:46 am
content: Yeah acid-core. I know that's a big no-no with electronics, but this is specifically made for electronics...just you have to wash it off...Hmm, well I guess when I buy my FX-888 I'll buy a spool and tell you guys what I think.

author: JuKu
author_rank: Frequent Contributor
timestamp: November 29, 2012, 06:27:04 am
content: In a previous job, we used organic flux. It was made out of orange peels (smelled like that, too). Basically, it was super strong citrus acid. Worked very well, rinsed off easily but being acid, a must-clean.

author: Psi
author_rank: Super Contributor
timestamp: November 29, 2012, 07:25:07 am
content: Quote from: FenderBender on November 29, 2012, 02:46:30 amI have exactly the same issue, one of my projects is on gloss black PCB and you can still see the white residue left behind even after cleaning with a stiff brush and Isopropanol . (the residue covers up the black gloss making it quite obvious)If you rub it with a cloth you can remove it and get the gloss back but the cloth always catches on the throughhole components so cleaning it all off is almost impossible.I'm still looking for a solution.

author: poptones
author_rank: Frequent Contributor
timestamp: November 29, 2012, 07:46:14 am
content: We used 331 way back when because we wanted to cut down our Zep bill. What we did was put the boards in a dishwasher, then put them in an oven to bake for 24 hours before doing QC. I don't remember any problem with films. The thing I hated about the organic stuff is the way it sputtered and the joints always looked a bit cold.I prefer regular rosin core 2% silver bearing. And I can't see how anyone can solder with that chinese stuff, at least what I had would instantly corrode the tip and so refuse then to melt. It was, literally, useless as solder.

author: jeroen74
author_rank: Frequent Contributor
timestamp: November 29, 2012, 07:57:46 am
content: QuoteMaybe use a specially formulated PCB cleaner? I always use Electrolube Fluxclean, but found Chemtronics works well too. Both contain some pretty strong solvents, like paint thinner I guess.I used to submerse the PCB in a bath of this stuff, but that didn't work too well, you only end up redistributing the flux residue as a smeary film all over the PCB and wasting loads of this expensive stuff. I found that simply using the little attached brush and dotting with tissue paper works much better. The paper sucks up the residue.

author: Psi
author_rank: Super Contributor
timestamp: November 29, 2012, 12:47:38 pm
content: i did try some proper PCB flux remover but it really doesnt agree with my skin. Caused some sort of contact dermatitis for a few weeks.Obviously the best solution is to wear gloves but its still something id rather avoid.One thing id like to try is a ultrasonic bath in some sort of solvent but im not sure if the components would like the vibration.

author: jeroen74
author_rank: Frequent Contributor
timestamp: November 29, 2012, 12:52:30 pm
content: I think most components don't bother ultrasonic cleaning, but I've seen datasheets of LEDs (IIRC Osram Golden Dragon) that explicitly state no ultrasonic cleaning is allowed.These flux removers are indeed quite aggressive to the skin.

author: Conrad Hoffman
author_rank: Super Contributor
timestamp: November 29, 2012, 01:52:58 pm
content: I've used 331 for years and it's wonderful. I only use it on new boards built from scratch. Warm water and a toothbrush, a little detergent, and it comes out clean as a whistle. Clean both sides and rinse thoroughly. Fail to clean it off within a day or two and you get what you deserve.

author: StubbornGreek
author_rank: Frequent Contributor
timestamp: November 29, 2012, 03:13:21 pm
content: Just an FYI, I use Kester 44 and the 'secret' to removing flux residue is to: 1) clean as you go, not at the end and 2) after the acid (or tooth) brush and IPA, drop a piece of your lint-free cloth of choice over top and use the brush with a bit of fresh IPA over top - works great.As far as flux remover, I hate that stuff... Its very aggressive on your skin and you have to use a ton of it.For the 331, I'd imagine hand washing or even dishwasher will work but I'd hate to see results of the 'glob' that got away.

author: IanB
author_rank: Super Contributor
timestamp: November 29, 2012, 03:29:53 pm
content: Quote from: Psi on November 29, 2012, 07:25:07 amAre you both rinsing off the residues after loosening the flux with the brush? Brushing alone will simply move the flux around over the surface to be deposited back when the solvent evaporates.What you need to do after brushing is hold the board over a tray and rinse it off with a stream of clean IPA from a squirty bottle.It's just like washing your car. If you don't rinse it off with clean water after the soap and brush you will get soap residues all over the paintwork when it dries.

author: G7PSK
author_rank: Super Contributor
timestamp: November 29, 2012, 03:36:49 pm
content: Quote from: jeroen74 on November 29, 2012, 12:52:30 pmUltra sonic cleaning is very aggressive in itself, I once left some clock parts in an ultra sonic cleaner with toluene as the cleaning fluid I came back after about 30 or 40 minuets and some of the cogs looked like they were made of lace. So it would only take a very short time to cut through copper traces on a board.

author: IanB
author_rank: Super Contributor
timestamp: November 29, 2012, 05:02:57 pm
content: Quote from: G7PSK on November 29, 2012, 03:36:49 pmBut the clock parts were made of plastic? Toluene will not affect metal parts.

author: SeanB
author_rank: Super Contributor
timestamp: November 29, 2012, 06:09:40 pm
content: I had an ultrasonic cleaner that used 1,1,1 Tricholetethylene. It would destroy metal by scrubbing it if you left it in too long.

author: FenderBender
author_rank: Super Contributor
timestamp: November 29, 2012, 10:08:57 pm
content: Quote from: IanB on November 29, 2012, 03:29:53 pmYes this is even after going under the sink rinsing and continuing to brush! I guess I must be doing something wrong, but I've just had a terrible time with it.

author: IanB
author_rank: Super Contributor
timestamp: November 29, 2012, 10:41:03 pm
content: Quote from: FenderBender on November 29, 2012, 10:08:57 pmI'll have to check what solder I use. I can't remember, but I do remember it has rosin flux.Note that if you try to rinse off with water it will knock the flux out of solution and cause it to be deposited out on the board. It's probably best to rinse off with solvent rather than water as rosin flux is not soluble in water.

author: jeroen74
author_rank: Frequent Contributor
timestamp: November 29, 2012, 10:45:32 pm
content: I wonder if there is any surfactant? you could add that keeps the flux in solution and prevents it from deposition back onto the PCB, ideally as some kind of crust that floats on top of the bath fluid.

author: Psi
author_rank: Super Contributor
timestamp: November 29, 2012, 11:08:41 pm
content: Quote from: IanB on November 29, 2012, 03:29:53 pmYeah, i think i need to buy a large bottle of IPA, my current bottle is quite small so i've not tried rinsing the whole pcb in it.The problem is there are restrictions on buying the stuff. People drink it and its used for some drug manufacture.So it's hard to get a large quantity.

author: nukie
author_rank: Frequent Contributor
timestamp: November 29, 2012, 11:52:04 pm
content: I use a paint brush with semi hard bristle. I use lighter fluid first. Then finish off with IPA. I flick the brush bristles as I scrub the flux so the liquid will fly off with the flux as I scrub. I do this over a bucket to collect the waste. This will remove the flux and prevent white deposits. And dont dip the brush in to the IPA bottle it will contaminate the liquid.I don't know why even if they claim its rosin flux, different solder requires different solvent. Sometimes methyl spirit, some clean well with lighter fluid, some IPA. I am looking into white spirits next. Just try and experiment.For larger boards or low volume production I use our locally made Chemtools bio degradable water based flux remover followed by a demineralised rinse. This works very well for me last few years.tapatalk