Recommendation for an electrical cored solder

[Dog Star]

The time has come... I have used the last of my Ersin Multicore solder and I need to purchase some solder which is suitable for baseboard wiring where there is no opportunity to rinse the joint to neutralise the effect of the flux.

What product / supplier does WTers recommend please?

thank you, Graham

 

[ZiderHead]

The very best is Multicore™ Sn62, its 62/37 with a trace of silver, 179deg IIRC. It is eyewateringly expensive though, but if you use the 0.5mm and only use whats necessary so theres no waste its not so bad. I use it for brass too as its what Ive always soldered with so I'm used to it

Any of the Multicore™ leaded solders are fine, if you use a hot enough iron and just enough solder to make a clean joint the flux burns off nicely. Cheaper solders use cheaper flux, which means they don't flow or tin as well and leave more, nastier residue. Available from Farnell/RS as usual.

 

[Steve Cook]

I've always used Carrs Speedy solder Graham because the last time I checked it mentioned its suitability for electrical connections where one couldn't clean the joint afterwards. Looking at the Carrs site now, that is no longer mentioned, however I plan to carry on with it as I've found it easy to use and have had no suspect after effects. I've no idea what spec it is other than resin cored.
Steve

 

[Dog Star]

Any of the Multicore™ leaded solders are fine, if you use a hot enough iron and just enough solder to make a clean joint the flux burns off nicely. ... Available from Farnell/RS as usual.

Thank you Bill, I ought to have thought to check availability other than to be persuaded, by what is avaialable from our local "D-i-M" stores, that Ersin products were no longer available.

I've always used Carrs Speedy solder Graham because the last time I checked it mentioned its suitability for electrical connections where one couldn't clean the joint afterwards. Looking at the Carrs site now, that is no longer mentioned, however I plan to carry on with it as I've found it easy to use and have had no suspect after effects. I've no idea what spec it is other than resin cored.

Thank you Steve, I can call C&L to check.

As a stop gap measure I tried a cored solder wire (code N29AR) from Maplins... marked as lead free (99%Sn and 1%Cu). Whilst the solder does what is needed the result is not pretty. I am soldering brass strip (1.0mm x 0.2mm section) on to a 3cm square pad of copper-clad paxolin (as described in the Hartley Hills topic) and the soldering iron needs to be at maximum (425 degrees) to get the solder to flow... not too smoothly at that... too many blobs for my liking and deserving of an admonishment from Mr. Locomodels.

regards, Graham

 

[ZiderHead]

Yup solder-free solder is horrible stuff to work with, stick with decent rosin-cored leaded. Maplins didn't stock any last time I checked, however auto parts stores generally have the real deal. Both my local auto places have Ersin/Multicore 60/40, I think Halfords does too. It will be the thicker stuff but thats fine for power wiring like cars and baseboards, the 0.5mm is much easier to use for circuits and small components.

Edit: Lead free is not only harder to work with and less pretty, its more brittle too even when soldered perfectly. Never seems to flow properly, it feels and looks a bit sludgy and doesn't seem to bind to the metal properly so its easy to get a dry joint. At least with 60/40 you know that shiny = good, dull = do it again. Sn62 is even better because its eutectic (sp?) so it sets instantly rather than over a small temp range.

 

[S7BcSR]

Graham

I have 3 unused tubes of Ersin Multicore Solder, you are welcome to one of them as I will never use all that I have got.

Regards
Rob

 

[daifly]

Yup solder-free solder is horrible stuff to work with

I think I've spotted why!

 

[Dog Star]

I have 3 unused tubes of Ersin Multicore Solder, you are welcome to one of them as I will never use all that I have got.

Yes please.

 

[S7BcSR]

Just picked this up via the alerts, so my apologies for not responding sooner. Will you be at Reading on Saturday, if so I will bring it with me.

Rob

 

[Steph Dale]

I've just seen this thread, one thing that doesn't appear to have been picked up so far is that you can't allow lead contamination of lead-free solder; that's where the brittleness and lack of durability comes from: lead embrittlement.
Used correctly lead-free is much more reliable than leaded solder, even eutectic. The trick is to work it with dedicated tools (so not the same iron or bit you use for assembling etched brass kits! ).
The 'rules' are set by JEITA (Japanese Electrical and Information Technology industry Association) and are basically that rework of cleaned substrates should be performed with the known solder where possible. Where there is doubt as to the solder used then leaded should be used as lead-free contamination of leaded solder is benign; whereas, as mentioned above, lead contamination of lead-free solder is problematic.
I hope that adds something useful to the thread and at the very least the clarification should be useful.
Steph

 

[Dog Star]

... one thing that doesn't appear to have been picked up so far is that you can't allow lead contamination of lead-free solder; that's where the brittleness and lack of durability comes from: lead embrittlement.

Thank you for this comment, most useful and interesting.

Given that "ye olde solda" of ages past included lead, does "lead contamination" of lead-free solders lead to brittle behaviour with all / any lead-free solder? Or is the brittle nature of contanimated lead-free with specific lead-free solders?

thanks, Graham

 

[OzzyO]

I Where there is doubt as to the solder used then lead-free should be used as lead-free contamination of leaded solder is benign; whereas, as mentioned above, lead contamination of lead-free solder is problematic.
I hope that adds something useful to the thread and at the very least the clarification should be useful.
Steph

So if I'm reading this correctly, you can use lead free on top of lead solder with no problems.

But if you use lead solder on top of lead free you will have problems.

Sod it. I'll keep using lead solder for as long as I can get it.

OzzyO.

 

[ZiderHead]

Sod it. I'll keep using lead solder for as long as I can get it.

 

[iploffy]

Whilst lead free solder was made more difficult to buy it was not outlawed. The giant electronic firms moved to lead free because they had to it became law, something to do with recycling I think, but still sold leaded solder if you wanted it (thank god)

 

[Dikitriki]

Hi

One other point that seems to have been generally overlooked - or ignored - is that lead based solders (or even white metal castings) cannot be used in electrical products destined for sale in Europe. Restriction of Hazardous Substances legislation.

Which means, taken to it's logical conclusion, and on the assumption that an engine is an 'electrical product', that any professional modeller is almost certain to be breaking the law.

Daft, innit?

Richard

 

[Steph Dale]

Graham, any lead in any lead-free solder; even Carrs 254 used to come with a label warning about use with lead solders. This also applies to silver-solders so silver-soldering a crank on to a Slaters axle (leaded steel) isn't a great idea either.

Sorry Paul, my typo resulted in you getting it the wrong way round: Thanks for pointing it out, I've now corrected the original post.

Ian, Yep you're referring to the WEEE directive, relating to disposal of electrical equipment containing heavy metals.

 

[OzzyO]

Where there is doubt as to the solder used then leaded should be used as lead-free contamination of leaded solder is benign; whereas, as mentioned above, lead contamination of lead-free solder is problematic.
I hope that adds something useful to the thread and at the very least the clarification should be useful.
Steph[/quote]

So rereading it, leaded should be used for repairs, "as lead-free contamination is benign (Collins dictionary, kindly, favourable).

Lead contamination Etc. is problematic.

This could be read in two ways,

1] that you can use leaded for all repairs as the use of lead solder will be OK.

2] But if you use lead-free on a leaded joint you will have problems!

If that is the case, why will it be OK in one case but not the other?

In case 2, as lead-free melts at a higher Temp. it could break down the leaded solder and cause problems.
In case 1, the lead-free has already tinned the parts and will not remelt. A bit like when we use 180Deg. solder to tin the brass parts before using 70Deg. solder to attach W/M parts.

That's how I'm starting to read this, I maybe wrong.

So don't use lead-free on top of lead solder, full stop.

Better idea. Don't use lead-free at all.

OzzyO.

 

[ZiderHead]

Used correctly lead-free is much more reliable than leaded solder, even eutectic.

Ive got to disagree with this - even used correctly (which is much harder to do than with leaded) lead-free joints are inherently less reliable due to the brittleness of the alloys. Googling "lead-free solder brittle fracture failure" returns pages of research confirming this.

 

[Steph Dale]

Jon,

Fair enough. Reliability engineering is my discipline and I've got conclusive evidence from safety-critical applications that, when processed correctly, lead-free is more reliable.

The issue, as such, isn't the reliability; it's the correct processing.

Steph

 

[ZiderHead]

Thats interesting, in that case I'd guess there are some newer lead-free alloys out there if they can equal or exceed the performance of leaded? The correct processing is a problem for the hobbyist though - we don't flow solder using computer-controlled machines in clean rooms under tightly controlled conditions, we do a bit of bodging using whatever iron we have lying around, and not always with the luxury of sitting at a bench!

The contamination bit is worth considering. Solder pads on boards must now be tinned with lead-free because sometimes when I put a blob on there ready to accept a tinned wire it has that murky lead-free look. If it does the solder sucker comes out and it gets a clean blob. Any wires I haven't tinned myself get the snip, strip and tin treatment. This isn't to avoid contamination causing brittleness, just for ease of work and rework.

Of course its always best to avoid stress on the joints by putting in a decent service loop and using some kind of strain relief, makes reworking possible too. Makes me wince seeing some electronic wiring, where the wires are stretched so tight you could play a tune on em!