Opinion on Solder Wire

[tooki]

Hi OK about Lead free and i stand corrected if all on this topic are using lead free but a suspect not

I use both, depends on the job.

The line ( Honestly, for most soldering, it makes not an iota of difference whether one uses leaded or lead-free. )  i wonder if other agree with you considering mixing is not recommended

What’s unclear to you?
For most soldering jobs, one won’t notice any substantial difference (the entire opposition to lead-free being that it’s “hard” to use). I.E. the difficulty level is the same.

As for not mixing: yeah, so don’t mix them. Certainly not in a joint, but better not in an entire device. Rework should be done using the same kind originally used. If a leaded joint has to be switched to lead-free (if somehow you absolutely, positively cannot get any leaded solder), then it should ideally be “flushed” with fresh solder several times to remove any traces of lead.

“It makes not an iota of difference” was referring to the process, not the product.

ok the person that clams to be his job and quotes (If, at this point, you can't manage hand-soldering with lead-free solder, then maybe it's time to consider another hobby.)
I think this is harsh and not in the spirit of helping

A lot of us are growing tired of the constant, largely unfounded whining about lead-free.

From the whining you’d think it was a million times worse, and it’s just not. Is it AS nice to work with as leaded? No, all else held equal. But other factors play a bigger role, like the iron, tip, the joint itself, and the flux. An easy joint is still going to be easy with lead-free, and a difficult joint would still be difficult with leaded.

my only response is my repair and rework is often to deal with dry or cracked solder joints that were made using lead solder also a do not deal with the domestic market
manly test and measurement and the Defence market but I am open to advise on the best lead free solder that is available so more open minded to lead free after reading this topic

For repair you really need to have both anyway, so…

There are plenty of discussions here on solder recommendations, including earlier in this thread.

[Paul B]

Hi  tooki
as i explained i am open to being taught how to use lead free solder

you talk about Flux  could someone come back with recommendation on Flux to use with lead free solder

PS  during my apprenticeship copper became difficult to get and i did learn to solder aluminium wire  that was a pain and hopefully all will be removed soon as the last bit i had problems with was 5 years ago in Brighton south coast England
Paul B

[eugene]

The only lead free solder that I've used is Kester (don't remember the part number) and I found it significantly more difficult than Kester leaded to get a clean looking joint. And here I'm mainly talking about appearance; I don't have too much trouble getting a mechanically and electrically good joint. I am willing to believe that there are other lead free solders that are easier to work with, and I will look for them. But, as long as I can continue to buy good leaded solder for prototypes, I will likely continue to use it, even if it only looks better.

As for flux, I vastly prefer water wash when I can use it. Yes, washing is an extra step (and must be done thoroughly) but I like a flux free board. Again, it's mostly a matter of appearance, not performance. Having said that, it MUST be washed away, so one must be careful with some ICs like QFN where the flux can get trapped and be difficult to remove. I'm still looking for a no-clean flux that is water soluble and easy to clean but doesn't need to be cleaned.

[Paul B]

eugene thank you for your input
do you have any documentation ,  history of degradation of solder joints , tracks , components through not washing the flux off
Paul b

[eugene]

Sorry, I can not provide documentation or references, only personal anecdote. I have seen I have seen metal components, leads, copper, even tools become corroded when in contact with water wash flux for too long. This is with Kester 2331 which is known to be both corrosive and conductive. I have only a little experience with Kester 977, which is also water soluble, but is not corrosive or conductive. The 2331 just works so well! Solder wetting is instant and easy. If I have bridging on fine pitched parts I can often dispense some 2331, run the iron over the area remelting the solder, et viola! The bridging is gone leaving perfect, beautiful solder joints on every pin.

In the end, no lead, no clean solder can be used to get good results. I have techs that will use it all day without complaint. But, they smile and say "thank you" if I tell them they can use Kester 6337 leaded solder and Kester 2331 water wash flux.

[wizard69]

I've always have used Kester for hand soldering.   That is when I've had control over the solder.

That being said it would have too be an extremely poor solder not to work, given components in decent condition.   60/40 is pretty forgiving.   If you are in a situation where poor components or wire is an issue then you will likely benefit from additional flux.   That is true of any Rosin core solder though.

Hi, guys. I know this might be a silly question but I was wondering if any of you have any good suggestion about what brand of solder is best for through hole soldering. It needs to be leaded, 60/40 and 0.7mm. The problem is that there are so many brands out there that it got confusing which one to purchase. 

[wizard69]

Towards the end I noticed a bunch of comments about silver bearing "lead Free" solders and mixing of such on a circuit board.    Not to be a pain but if you are working on a board, how do you even know what sort of solder it was assembled with??   I'm serious here, any board work I've done over the years I just use leaded solder and get on with it.

I can't imagine it making a huge difference due to the fact that the minute you heat up the solder and melt it into a joint the composition of the alloy is going to change.   

[tooki]

Many lead-free boards from the transitional period state Pb-free right on them. Any commercial product made from around early 2006 is lead-free (except for the few exempt product categories, which you’d know about if you were dealing with them).

Whether it’s silver-bearing or not isn’t the issue.

[Neomys Sapiens]

@tooki: can't find the reference right now. But I did read it somewhere exactly as stated. Although I can remember the thing about the tips too.

[tooki]

The only situation I’m aware of where silver-bearing solder matters is rework on silver-plated ceramic, where the silver content prevents the plating from dissolving away. Classic example is vintage Tektronix equipment with ceramic terminal strips. But if you find the reference, please share!

[nigelwright7557]

The top reputable brands are usually good. Buy from RS or Farnell.
I fell foul of some cheap ebay solder that barely melted and left big blobs.

[nigelwright7557]

Many lead-free boards from the transitional period state Pb-free right on them. Any commercial product made from around early 2006 is lead-free (except for the few exempt product categories, which you’d know about if you were dealing with them).

Whether it’s silver-bearing or not isn’t the issue.

The space industry used lead free solder many years ago.
Worked fine to start with but after a few years pcb's started failing with solder whiskers developing and causing shorts.

[wraper]

And for hobbyists in Europe, it’s a moot point anyway, since it’s now illegal to sell leaded solder to consumers there. So people are going to have to get used to lead-free anyway, so whining is stupid and pointless.

Any written source on that for following up? I can still buy my favourite Stannol with 0.2% halide containing flux If I should stock up, I should do it sooner than later.

Some retailers (especially small shops) are just ignoring the law*. It’s been in effect for several years now. See https://ila-reach.org/2018/01/new-restrictions-and-labelling-requirements-affect-lead-from-march-1-2018/

*the law restricting the sale of lead solder to consumers is the REACH directive. It’s separate from RoHS, the directive disallowing the use of lead solder in finished electronics.

Two largest hardware retailers in Latvia (Estonia and Lithuania too) happily sell SnPb solder to everyone as if there is no law. Yet stupid TME does not sell it outside of Poland even to commercial customers.

[tooki]

Many lead-free boards from the transitional period state Pb-free right on them. Any commercial product made from around early 2006 is lead-free (except for the few exempt product categories, which you’d know about if you were dealing with them).

Whether it’s silver-bearing or not isn’t the issue.

The space industry used lead free solder many years ago.
Worked fine to start with but after a few years pcb's started failing with solder whiskers developing and causing shorts.

No, they didn’t use lead free solder. NASA’s reports about tin whiskers refer to pure tin plating on component leads.

[taste_tester]

I tried a roll of MG Chemicals  63/37 solder in a friend's workshop last year and every time I use Kester since then is a miserable experience. Even Kester 245 is "just ok" to me now...
I only use the MG Chem any time I can for PCB Repair/Rework because it cuts into & blends with very old solder much easier than any of my Kester [except organic core, of course] so it's often my first choice. I do maintain that it makes desoldering just a bit easier.
The MG Chem makes larger solder joints which may or may not be something you care about compared to the Kester.
If you could get away with it, I'd say just use Kester organic core and wash your boards off after soldering.

[free_electron]

Kester, Multicore , Alpha Metals , Indium Corporation.

Get a eutectic alloy.

[exmadscientist]

Get a eutectic alloy.

Do not buy 60/40. Just don't, unless you are desperate or something. You want 63/37 or 62/36/2. Don't throw 60/40 out or anything, but do not buy more.

Regarding lead-free, I've come to hate the older alloys (SAC305 and friends). The Sn100C family is much, much more pleasant to use. (I've only tried licensed genuine Sn100C, because how often do you buy solder anyway, but I'd expect the patent-avoiding clones aren't very different for hand work.) It's close enough to SnPb that I wouldn't scream too loudly if I was stuck with it for the rest of my career.

[wraper]

Get a eutectic alloy.

Do not buy 60/40. Just don't, unless you are desperate or something. You want 63/37 or 62/36/2. Don't throw 60/40 out or anything, but do not buy more.

Regarding lead-free, I've come to hate the older alloys (SAC305 and friends). The Sn100C family is much, much more pleasant to use. (I've only tried licensed genuine Sn100C, because how often do you buy solder anyway, but I'd expect the patent-avoiding clones aren't very different for hand work.) It's close enough to SnPb that I wouldn't scream too loudly if I was stuck with it for the rest of my career.

SN100C patent has expired but name is still trademarked so anyone is free to make the exact composition and just name it differently.

[tooki]

I tried a roll of MG Chemicals  63/37 solder in a friend's workshop last year and every time I use Kester since then is a miserable experience.

Which one? They have 63/37 in both no-clean and RA.

The MG Chem makes larger solder joints which may or may not be something you care about compared to the Kester.

The size of the joint comes from how much solder you apply, and that in turn has to do with the diameter and with how much you feed in. (Sure, heat and flux type make a difference in how much spread you get, but not the amount of solder as such.)

Edit: typo

[free_electron]

sn99c or sn100c for lead-free. ditch that sac305 stuff. that is first-generation and trouble...

of course, if you need ot do repairs you need it. NEVER mix alloys !

[mariush]

Which one? They have 63/37 in both no-clean and RA.

ra means rosin activated , no-clean means just that, that cleaning the flux is (in majority of the time) not required. Some RA fluxes must be cleaned with isopropyl alcohol or other solvents otherwise they'll continue to corrode the surfaces they're on.

No-clean should be slightly milder, less active than RA. If you work with new/clean parts or relatively new parts, no-clean would be fine.
If you deal often with very oxidized parts, go for RA.


As for diameter I prefer around 0.5mm - i have some multicore 63/37 with 2.2% no clean flux, in 0.56mm diameter (well, whatever that amounts in inch)
I was debating back then if I should go for 0.4mm but that can be too thin for some jobs (and you lose fine control when you're feeding a lot of solder on bigger soldering jobs) and also the thinner wires tend to have less flux inside.
With 0.5mm I can always cut a length of solder and fold it in two to get a thicker diameter solder wire for bigger soldering jobs, and as a single wire it's thin enough for surface mount stuff.

[wraper]

sn99c or sn100c for lead-free. ditch that sac305 stuff. that is first-generation and trouble...

of course, if you need ot do repairs you need it. NEVER mix alloys !

SN100C is a completely different beast compared to any simple SnCu alloys. They simply don't like to flow/wet anywhere close to SAC305 or SN100C. So solder flows like garbage unless come with a quite active flux or PCB surface has perfect solderability (PCBs from cheap Chinese prototyping services usually don't).

[tooki]

Which one? They have 63/37 in both no-clean and RA.

ra means rosin activated , no-clean means just that, that cleaning the flux is (in majority of the time) not required. Some RA fluxes must be cleaned with isopropyl alcohol or other solvents otherwise they'll continue to corrode the surfaces they're on.

No-clean should be slightly milder, less active than RA. If you work with new/clean parts or relatively new parts, no-clean would be fine.
If you deal often with very oxidized parts, go for RA.

I don’t think you understood my question. I know what the flux types mean, I didn’t ask for a definition. I asked taste_tester which flux type is used in the solder he liked, because the flux is what makes it flow the way they like. MG Chemicals makes 63/37 solder wire in two types: RA and NC. But taste_tester didn’t say which one, he only said it’s MG Chemicals.

[tooki]

sn99c or sn100c for lead-free. ditch that sac305 stuff. that is first-generation and trouble...

This agrees with my experience. The SN100C I’ve used (this one, calls it SN100Ni+ but is made under license; datasheet below) flows better than any of the SAC305 I’ve used, and produces nicer looking joints. And it’s not expensive at all: https://www.reichelt.com/ch/de/lead-free-solder-with-copper-0-5-mm-250-g-lz-f4-bf-0-5-250-p258990.html

[Bud]

In my personal experience Kester is nicer than MG Chemicals for a same given type.