Wire Question - Page 1
Forum section: electronics / projects

author: bostonman
author_rank: Super Contributor
timestamp: August 17, 2023, 01:32:45 am
content: I have a roll of this wire:https://www.digikey.com/en/products/detail/belden-inc./9977%2520002100/7389132?utm_adgroup=General&utm_source=google&utm_medium=cpc&utm_campaign=PMax%20Shopping_Product_Zombie%20SKUs&utm_term=&utm_content=General&gclid=EAIaIQobChMI_vCcoMXigAMVoPHjBx2HrwCTEAQYASABEgLmnfD_BwEFor whatever reason, I couldn't get solder to stick to the wire. I heated it, applied 63/37, and the solder just kept running off. Eventually I got a blob of solder to encase the wire, however, once cooled, I could wiggle the wire meaning solder didn't adhere to the wire.Is the wire made of some odd material? The description states it's copper tinned.

author: Jackster
author_rank: Frequent Contributor
timestamp: August 17, 2023, 02:05:42 am
content: Flux?

author: IanB
author_rank: Super Contributor
timestamp: August 17, 2023, 02:14:28 am
content: Quote from: bostonman on August 17, 2023, 01:32:45 amI think we have no clue what the reason is.QuoteIt's plain, ordinary, tinned copper wire. I assume it is silver in color when you strip back the insulation?Nothing explains what you describe.That said, when I wish to tin wire, I always poke the wire into some paste flux before applying solder to it. Solder should bond perfectly fine using only the flux in the solder wire, but in my opinion you cannot have too much flux when soldering.

author: bdunham7
author_rank: Super Contributor
timestamp: August 17, 2023, 02:21:48 am
content: Try more heat, even if you think your iron is already plenty hot.

author: Kim Christensen
author_rank: Super Contributor
timestamp: August 17, 2023, 02:48:28 am
content: You have to strip the red insulation off first.All kidding aside, sounds like you need some flux on the wire before applying solder. Does the solder you are using have a flux core or is it solid?Belden is good quality wire. It's not like it's some cheap copper coated aluminum stuff from AliExpress. So if it has been freshly stripped and is untarnished, it should take solder well.

author: IanB
author_rank: Super Contributor
timestamp: August 17, 2023, 03:16:10 am
content: However, if you heat the solder on the iron and let the molten solder drip onto the cold wire, then the solder will blob up and will not flow onto the wire. This is one way to reproduce the observation made by the OP.Failing to remove the red insulation is indeed another way.

author: srb1954
author_rank: Super Contributor
timestamp: August 17, 2023, 08:36:23 am
content: Quote from: Kim Christensen on August 17, 2023, 02:48:28 amIf it a really old reel of wire the tin coating may have become tarnished and will require either a really aggressive flux or even abrasive cleaning to remove the tarnish so that the solder can wet the metal surface.

author: bostonman
author_rank: Super Contributor
timestamp: August 17, 2023, 03:20:35 pm
content: It must be the solder.I tried soldering the same wire at work and the solder at work took to it. The solder I used at home was an old roll from a previous job that was being thrown away because it had "expired" (the date was 2009); although I've never heard of solder going bad.

author: TimFox
author_rank: Super Contributor
timestamp: August 17, 2023, 04:12:49 pm
content: The "old roll" of solder was labeled 63-37, which is the normal 63% Sn, 37% Pb eutectic alloy.However, it is possible to buy solder wire that does not have a flux core: was this true of your old solder?Flux, when heated, is used to reduce (in the chemical sense) any oxides on the surface to be soldered so that the molten solder "wets" the surface properly.

author: bdunham7
author_rank: Super Contributor
timestamp: August 17, 2023, 05:22:00 pm
content: Quote from: bostonman on August 17, 2023, 03:20:35 pmWas that with the same iron or a different iron? Soldering tinned parts is different than soldering to bare copper, I would expect it to work perhaps even with no flux and certainly with 'expired' rosin-core flux. Is your 'bad' solder labeled and does it say what sort of flux it has?

author: bostonman
author_rank: Super Contributor
timestamp: August 17, 2023, 06:02:13 pm
content: I'll check the solder later.It was a different iron and different solder, wire was the same. Maybe my soldering iron tip isn't any good.

author: donlisms
author_rank: Frequent Contributor
timestamp: August 17, 2023, 11:53:11 pm
content: Maybe it's not. Can you solder other things? Do some tests by swapping out one element at a time?When things get weird... make no assumptions.

author: bostonman
author_rank: Super Contributor
timestamp: August 18, 2023, 01:05:43 am
content: I’ll try soldering something, but believe this roll has been used plenty of times as I only have two rolls handy while my others are stored away.See attached picture for the solder I used.

author: TimFox
author_rank: Super Contributor
timestamp: August 18, 2023, 02:49:18 am
content: My Spanish is non-existent: does any of that label mention flux?

author: T3sl4co1l
author_rank: Super Contributor
timestamp: August 18, 2023, 02:57:00 am
content: RMAhttps://www.kester.com/DesktopModules/Bring2mind/DMX/API/Entries/Download?Command=Core_Download&EntryId=1018&language=en-US&PortalId=0&TabId=96I haven't had any new wire that doesn't solder, but I have seen old stuff that, more or less either the tin grew extra oxide just sitting there, or there's some kind of reaction with the PVC, it doesn't work very well in any case and either needs a ton extra flux and heat, or just scrape/sand it like it's enameled. I would say ballpark 10-30 years required to get like that?Tim

author: IanB
author_rank: Super Contributor
timestamp: August 18, 2023, 04:40:44 am
content: I also don't see any mention of flux on that picture. This is easy to check: just cut the wire cleanly and see if a flux core is visible?Also, professional soldering guides instruct you to clean the outside of the solder wire until it is shiny before using it. For example, scrub the outside of the wire with a cleaning wipe soaked in IPA. Otherwise the accumulated oxides can interfere with the soldering process.Furthermore, I always have a container of paste flux to hand, and I always dip the ends of wires in flux before tinning them.

author: konohimawm
author_rank: Newbie
timestamp: August 18, 2023, 10:54:04 am
content: I always strip the insulation of the cable and dip it in cream flux before soldering.No matter how old the solder is, flux will always solve the problem.Flux-containing solders also contain some resin, making it difficult to clean the slag. That's why I recommend using flux-free types.

author: TimFox
author_rank: Super Contributor
timestamp: August 18, 2023, 01:49:24 pm
content: For most (not all) purposes, the residue from rosin-core flux solder is not a problem (although it may look icky).Some (non-rosin) fluxes are water soluble, and can be removed with hot water, but will absorb moisture and may degrade the circuit performance with unwanted conductance on the surface.

author: tooki
author_rank: Super Contributor
timestamp: August 18, 2023, 02:00:50 pm
content: Quote from: IanB on August 18, 2023, 04:40:44 amIt’s not obvious if you’re not familiar with Kester’s nomenclature: the “58/285” means type 285 flux (see datasheet linked by T3sl4co1l), 2.2% flux core size. (50 = 1.1%, 58 = 2.2%, 66 = 3.3%)My understanding of the 285 flux is that it’s a great flux for surfaces that are fairly clean and untarnished, but not aggressive enough for tougher tarnishing. Kester 44 is a better match for that.Adding external flux should take care of the issue.

author: jonpaul
author_rank: Super Contributor
timestamp: August 18, 2023, 09:49:12 pm
content: Plastic or rubber insulated wire can have oxidation on the tinned wire surface especially if the wire is old or exposed to weather, near water (ocean, lake, rivers) etc.We used an X acto knife t scrape the wire strands after stripping, and had no issues afterwards.The best solder is the 63/37 leaded, any RoHS or non eutectic has a plastic stage and needs a higher temperature.The best iron ever is r Metcal SmartHeat high frequency, our desing of the resonant mode power , SP-200.Bon ChanceJon

author: bostonman
author_rank: Super Contributor
timestamp: August 19, 2023, 12:13:26 am
content: Maybe it was not enough heat.Same iron (I didn’t even clean the tip), solder, wire, etc… and I was able to solder the wire to a resistor lead.

author: vk6zgo
author_rank: Super Contributor
timestamp: August 19, 2023, 01:13:10 am
content: Quote from: IanB on August 18, 2023, 04:40:44 amYou beat me to it!Back in the 1970s, I did a course called "High Reliability Hand Soldering", & amongst a host of other things, we were shown just how much crud accumulates on the outside of solder.They were also big advocates of using additional flux.I've followed their advice successfully ever since.Quote

author: tooki
author_rank: Super Contributor
timestamp: August 19, 2023, 07:55:38 pm
content: Quote from: jonpaul on August 18, 2023, 09:49:12 pmThe bolded pars are really not true.Eutectic lead-free solder alloys exist, like Sn95.6Ag3.5Cu0.9, Sn95.5Ag3.9Cu0.6, Sn95.5Ag4Cu0.5, Sn96.5Ag3.5, Sn99.3Cu0.7, and Sn99.3Cu0.7Ni0.05Ge0.009.The extremely common SAC305 is extremely close to eutectic (closer to eutectic than 60/40 is to 63/37, for example). Sn99.3Cu0.7 is very common for hand soldering, and it’s truly eutectic.

author: bdunham7
author_rank: Super Contributor
timestamp: August 19, 2023, 09:36:45 pm
content: Quote from: tooki on August 19, 2023, 07:55:38 pmI believe that is the trademark SN100C formula, which AIM states is eutectic, although the melting point is only 5C below tin so unlike Sn63Pb7 you don't get a significantly lower melt temp. SN100C certainly works well-no cold or dull joints, flows well and no plastic region.

author: jonpaul
author_rank: Super Contributor
timestamp: August 21, 2023, 12:41:36 am
content: SN100C was patented but that has exired.Several vendos now off it or similar, it has rel=llaced SAC305 , less costly and better performance.Still in non-roHS, vintage repairs, DIYers, the best solder is 63/37 An/Pb.Jon