Cored Solder - not behaving - Page 1
Forum section: electronics / beginners

author: BenKenobi
author_rank: Regular Contributor
timestamp: February 08, 2019, 12:33:38 pm
content: Posting this here to see if anyone can shed light - I'm no beginner but the responses may be useful to others.So - I have some 60/40 Multicore branded X32C solder that just won't flow, it isn't that old, it's 3 Core 1.5%, 22awg and it simply will not flow out - even if I use a flux pen in addition. It just beads regardless of temperature, whether I use the flux pen or not it doesn't matter (I tried this because I thought that 1.5% may be too little on a repair I'm doing)I've another roll of similar solder and it works a treat - must be 10 years old but it is absolutely no issue, 325 Deg.Yes the area has been cleaned, yes the pads have been tinned, yes I'm using a temperature controlled iron (CSI Premier 75W), I've tried temperatures between 275 and 350, I've tried with and without flux pen - this particular roll won't work no matter what I try. I don't think in 30+ years I've encountered anything like it, tempted just to throw it out but I'm too tight fisted to do so (I have 1kg of the stuff ...)Any suggestions ?

author: jmelson
author_rank: Super Contributor
timestamp: February 08, 2019, 08:02:18 pm
content: Quote from: BenKenobi on February 08, 2019, 12:33:38 pmWhere did you get it from? Are you SURE it is genuine, or could it be a fake product? Cut it with an X-acto knife and verify it rally has the flux core(s) in it. If you can't identify the flux core, then it is almost certainly a fake. Have you tried soldering a bare copper wire joint? Maybe some weird incompatibility with the plating on the PC board is causing it.Just a few random thoughts.Jon

author: BenKenobi
author_rank: Regular Contributor
timestamp: February 08, 2019, 09:55:59 pm
content: Actually came from one of our workshops when it got closed down, I've only recently found it amongst all kinds of other stuff. Historically the companies supplier was RS components, I can see what appears to be a core - too small to see clearly.It tins wires OK, but still doesn't flow how I'd expect, seems to prefer 300°C or slightly less, on vero board it doesn't work so well - it's almost 'sticky' if that makes any sense - once it is on the tip it is hard to get off (plated copper tips). To get a decent joint I need to dwell too long even with a tip far too large for what I'm doing - it almost behaves like lead free, adding extra flux from a pen doesn't seem to help.So I did a little more research - the flux it contains is a low fume halide free, and in the document below it is rated as a '2' for working with - "2 - very difficult to work with, time consuming, solder not flowing properly"So this is a characteristic of the solder and attempts to reduce the fumes - time to buy some good ol 5 core ...https://www.sserc.org.uk/wp-content/uploads/2014/02/Solder_Fume_Control.pdf

author: jmelson
author_rank: Super Contributor
timestamp: February 08, 2019, 10:22:28 pm
content: Quote from: BenKenobi on February 08, 2019, 09:55:59 pmOK, if it has some low-performing flux that has THEN degraded to even worse performance, I can imagine this might be what you are experiencing. And, some badly degraded flux might interfere with any flux you add to it. I HAVE, a long time ago, seen some very old solders that just didn't "work" anymore.Jon

author: stj
author_rank: Super Contributor
timestamp: February 08, 2019, 11:25:06 pm
content: http://www.bluethundertechnologies.com/wp-content/uploads/2012/12/henk_multicore_x32-10m_tds.pdfShelf Life: 725 Days

author: BenKenobi
author_rank: Regular Contributor
timestamp: February 08, 2019, 11:28:41 pm
content: That explains it. If it had a limited shelf life you would think that they would put it on the product label together with a manufacture date ...

author: sambonator
author_rank: Regular Contributor
timestamp: February 11, 2019, 09:01:34 am
content: Crap, I should probably stop using my 20 yr old Radio Shack 60/40 Rosin Core solder huh...?

author: Psi
author_rank: Super Contributor
timestamp: February 11, 2019, 09:13:51 am
content: Quote from: sambonator on February 11, 2019, 09:01:34 amIf it's still working well keep using it.The problems happen when people forget how well 'good' solder works or have never used good solder.They start to think their crap solder is normal.

author: Rerouter
author_rank: Super Contributor
timestamp: February 11, 2019, 09:19:55 am
content: The simple solution is solder so much that no roll lasts a full 2 years

author: Ian.M
author_rank: Super Contributor
timestamp: February 11, 2019, 09:29:33 am
content: If you melt the end with your soldering iron to seal it, rosin core solder does not go bad. If you don't melt the end, a decade or so later you may need to discard several inches to get to good flux core. If very old or improperly stored, it tends to build up oxides on the surface. These can be removed by pulling a length through a folded over green pan scourer then through a wipe wetted with IPA.No-clean flux core solder wont have enough flux to cope with surface oxidisation, and any solder with water washable flux core is likely to have a fairly short shelf life as the core is typically hygroscopic and highly corrosive when damp.

author: tooki
author_rank: Super Contributor
timestamp: February 11, 2019, 10:06:15 am
content: I wonder about that, simply because rosin is, for all intents and purposes, amber-to-be. Wouldn’t it, if anything, be a preservative of sorts?As for solder itself, my oldest solder is still from my childhood, bought at some point before 1992 (when we first moved from USA to Switzerland). All of that still works, even if it’s no longer got a shiny surface. The Radio Shack 60/40 I use for tip tinning and to mobilize old joints — I’ve come to prefer 63/37 for actually making joints. The only old 63/37 I have is a roll of really thin .015” (0.4mm) Kester with 282 flux I got from some (probably surplus) vendor out of the back of Popular Electronics. It was mothballed for probably 20 years before I got back into electronics a few years ago, and underneath the outer layer of tarnished solder, the layers below are still relatively nice and shiny!(Edit: I just did a bit of searching and it seems the Kester 282 solders are still made, and seem to cost about $125/lb for the thin stuff!!)

author: Cnoob
author_rank: Regular Contributor
timestamp: February 11, 2019, 10:15:38 am
content: The solder I favour is LMP type 362 dia 0.7mm which was purchased over 25 years ago and it still gives nice shiny joints using my pace wjs 100 set at 280 C

author: stj
author_rank: Super Contributor
timestamp: February 11, 2019, 02:21:43 pm
content: flux absorbs moisture from the air, try throwing away the first meter of it and testing again.btw, flux is not Rosin, that just happens to be the main ingredient - atleast in the past.

author: tooki
author_rank: Super Contributor
timestamp: February 11, 2019, 06:45:46 pm
content: Quote from: stj on February 11, 2019, 02:21:43 pmNobody said it was. I can’t speak for anyone else, but I mentioned it because it’s the primary ingredient in nearly all non-water-soluble fluxes for flux-core solder, as well as the main active ingredient in many liquid fluxes. (There are many, many kinds of rosin, which is why it can be made into no-clean fluxes and the like.)

author: Ian.M
author_rank: Super Contributor
timestamp: February 11, 2019, 07:25:10 pm
content: I think one needs to make the distinction between natural rosin, synthetic rosin and other mystery resins used as the main component of fluxes.Natural rosin on its own is a mild flux suitable for SnPb and high Sn on clean surfaces of easily solderable metals - either freshly cleaned copper, brasses and bronzes or tin plate, or reasonably new PCBs with immersion tin, ENIG or OSP finishes or clean HASL, and using components with clean unoxidised leads or terminals. Its more convenient dissolved in alcohol or mixed with petroleum jelly to form a gel or paste flux.However its more usual to have a small concentration of one or more activators mixed with the rosin to enable it to handle more oxide contamination of the pads, component leads and solder surface.N.B. Beware of rosin fluxes with ammonium chloride or zinc chloride activators which leave a corrosive residue making them unsuitable for electronics work.

author: tooki
author_rank: Super Contributor
timestamp: February 11, 2019, 07:28:31 pm
content: That’s all true, but frankly, faaaar afield of the scope of this topic, and even outside of most general discussions of electronics solder for a beginner.

author: Ian.M
author_rank: Super Contributor
timestamp: February 11, 2019, 07:59:47 pm
content: However solid rosin flux that doesn't contain hygroscopic acid chloride activators isn't significantly affected by humidity. I've never had to cut back more than a inch or two of rosin core solder to get to good flux core, that did the job of flowing well without significant spitting, even on a few 40 year old reels of solder that hadn't been touched for over 20 years and were stored in an unheated outbuilding.

author: GreyWoolfe
author_rank: Unknown
timestamp: February 11, 2019, 08:02:52 pm
content: Quote from: sambonator on February 11, 2019, 09:01:34 amOr my 22 year old PhillipsECG 60/40 rosen core. Thankfully, I only have a couple of feet left.