I'm returning a spool of solder. What i should replace it with?

[Basileus]

Hi, i have been looking into buying a spool (say 500/1lb) of general purpose leaded solder just to have it last a good time (considering how ROHS requirements are getting more and more stringent as time passes).

So far i have been soldering with a spool of Fixpoint 51062 (60/38/2% Cu, 0.56mm 2% No clean (maybe? it says nothing on the label)) and love it so much i wanted to get something as close as possible, so i bought a spool of Kester Solder 24-6337-8807 (63/37, 0.5mm, No Clean) from Amazon US and when i tested it was good. Joints are really shiny and look beautiful, theres only a small problem... The amount of flux is way way too low (1.1%) and this makes annoying to work on anything that isnt a spotless brand new pcb, and doesnt keep the tips clean as easily. When adding a small amount of solder to the tip, the fixpoint solder smokes quite a bit for a long length of time, while the kester one emits one single puff of smoke and just stops.

Because of this i have concluded this wasnt the all purpose kind of solder i was looking for. Looking for alternatives, it seems like the only other option on amazon us is kester solder with 3.3% 44 flux, which i would say its the polar opposite of the one i returned: lots and lots of RA not no clean flux which would make lots of brown flux residues and laborious to clean, so i'm not too sure its something i want to get myself into.

Digikey also seems pretty interesting because they stock spools with 3.3% 285 RMA flux, which might be a happy medium between the RA and no clean, as well as 2.2% 245 No Clean. For 3.3% No clean i could only find it in 0.8mm, which might be too thick when doing SMD.

So i'm currently on a standstill deciding what to do. Would 2.2% No clean be enough? Would 3.3% RMA be a better balance? Is 3.3% RA actually not that bad when it comes to residues and cleaning? I'm struggling to make a decision.

Any suggestions?

[Psi]

I use 2.2% for all my stuff and it works great, but it's all lead solder. So i dunno if that helps you.

[Ian.M]

No-Clean flux is cr@p for repairs and development.  No-Clean generally means less flux, and less active, and almost always seems to be harder to clean if you actually need to.   It has its place on a production line but is a snare and a delusion to hobbyists and development techs. 

If your component terminals and PCB pads aren't clean bright metal, use extra flux, applied before soldering.  Don't buy solder with more flux core or more active flux as then you are stuck with it making a mess and possibly causing surface leakage or corrosion if not thoroughly cleaned, even when you are assembling brand new fresh PCBs and parts.

Don't fall into the pitfall of buying any sort of water-washable flux - they are all unsuitable for hand soldering with either an iron or a hot air tool, unless you've got a heated ultrasonic cleaner to wash it, a high pressure hot water jet rinse cabinet to rinse it and a heated drying cabinet, as a single droplet of their residue under a chip will probably kill your board in under a year by corroding pins, tracks or vias.  Even if you have the equipment to wash off water-washable flux properly, never use it on stranded wire as you can never get all the residue out from between the strands under the insulation. 

[Someone]

Also dont get hung up on wire diameter, solder will only flow where its hot enough. As long as your tip is not so big that it will wick solder onto other pins/pads, then you can use thicker wire and apply it against the top of the joint into the iron.

0402 passives or 0.5mm pitch connectors with 0.7mm or 1mm wire is no problem.

[Jeroen3]

I've been using this stuff Weller T0051388599 Sn96,5Ag3Cu0,5 and it works just fine at 380c tip. Yes, leadfree.
Both 0.5 and 0.8mm.

And still some people complain about this stuff not having enough flux. You know, those people setting their iron to 450 because that solders nice and fast....

[HighVoltage]

The best general purpose solder I have ever used is KESTER SN63PB37
Not cheap, but really good.

[janoc]

If your component terminals and PCB pads aren't clean bright metal, use extra flux, applied before soldering.  Don't buy solder with more flux core or more active flux as then you are stuck with it making a mess and possibly causing surface leakage or corrosion if not thoroughly cleaned, even when you are assembling brand new fresh PCBs and parts.

This!

So many people don't add flux and then are surprised it is difficult to solder. I have even been told that I "should re-learn to solder if I need to add flux" by someone on Hackaday. It is mind boggling.

Flux needs to be added even when working on a freshly cleaned metal, 0.5mm solder wire will not have enough of it to not flash away too early  regardless of the stated flux content on the sticker. And it is an absolute must when touching up the joint - there is no flux left there otherwise.

For hand soldering I have always had good results with rosin based fluxes, the sticky gel stuff is good for SMD assembly. Both easily cleaned with some IPA.

[Psi]

The best general purpose solder I have ever used is KESTER SN63PB37
Not cheap, but really good.

yeah, that's what i use.   Type 285 (Mildly Activated Rosin Flux  ROL0)
Available in 1.1, 2.2 or 3.3% flux, (I get 2.2)

[Psi]

Flux needs to be added even when working on a freshly cleaned metal, 0.5mm solder wire will not have enough of it to not flash away too early  regardless of the stated flux content on the sticker.

I think that is going a bit far. Clean joints almost never need added flux. Unless maybe if you're using 1.1% flux core.
But I agree that flux is super important and adding some as needed is a must.

[tooki]

So far i have been soldering with a spool of Fixpoint 51062 (60/38/2% Cu, 0.56mm 2% No clean (maybe? it says nothing on the label)) and love it so much i wanted to get something as close as possible, so i bought a spool of Kester Solder 24-6337-8807 (63/37, 0.5mm, No Clean) from Amazon US and when i tested it was good. Joints are really shiny and look beautiful, theres only a small problem... The amount of flux is way way too low (1.1%) and this makes annoying to work on anything that isnt a spotless brand new pcb, and doesnt keep the tips clean as easily. When adding a small amount of solder to the tip, the fixpoint solder smokes quite a bit for a long length of time, while the kester one emits one single puff of smoke and just stops.

…

Any suggestions?

Yes. Try Kester 44 (classic RA). Works beautifully and is easy to clean off if you choose. 24-6337-0010 is the 0.51mm, 24-6337-0018 is 0.64mm, and 24-6337-0027 is the 0.79mm. (The latter is my everyday solder at home.)

But I also wholeheartedly agree with the suggestions to have flux on hand, too. It makes some jobs soooooo much easier and more successful.

[Psi]

Strictly speaking you should always clean 44 off the PCB.
With 285 cleaning is optional. But 285 is really only suitable for fresh clean joints/pcbs

[tooki]

Strictly speaking you should always clean 44 off the PCB.
With 285 cleaning is optional. But 285 is really only suitable for fresh clean joints/pcbs

Actually, no.

From the 44 datasheet: “44 possesses excellent fluxing ability; the flux residues are non-corrosive, non-conductive and
do not require removal for most applications under normal conditions of use.”

The 285 datasheet says: “285 flux residues are non-corrosive, non-conductive and do not require removal in most
applications.”

[Electro Fan]

The best general purpose solder I have ever used is KESTER SN63PB37
Not cheap, but really good.

+1 for Kester

Lots of Kester products to choose from including lead and no lead.

Some of the links in the post below are no longer good (years later) but the Kester product numbers still hold, I think.

https://www.eevblog.com/forum/reviews/who-would-like-to-teach-me-about-lead-free-soldering/msg271330/#msg271330

Edit:  added links below that summarize/describe some of the Kester product categories

https://www.nteinc.com/kester/wire-solder-selector-guide.php

https://www.nteinc.com/kester/wire-solder-leadfree.php

[Psi]

Strictly speaking you should always clean 44 off the PCB.
With 285 cleaning is optional. But 285 is really only suitable for fresh clean joints/pcbs

Actually, no.

From the 44 datasheet: “44 possesses excellent fluxing ability; the flux residues are non-corrosive, non-conductive and
do not require removal for most applications under normal conditions of use.”

The 285 datasheet says: “285 flux residues are non-corrosive, non-conductive and do not require removal in most
applications.”

Depends how long your want the product to last.  44 is RA  vs 285 RMA.

[tooki]

As long as it’s not running hot enough for the flux to melt, 44 is safe indefinitely — it’s not corrosive at all when in solid form.

[taste_tester]

MG Chemicals  cat. no 4865-2276 won my heart over not long after buying a lot of Kester.
I've never found a solder I enjoy using more!! I swear it's made my life easier for desoldering too but could never prove it.
I have Kester 24-6337-8807 as well, but if I was buying very large quantities for any reason, I'd buy some of that MG Chemicals which is 63/37 and 2.2% flux 22 gauge.