Which solder for electronics?

[Fred]

Hi,

I bough a reel of solder many years ago and I still have plenty left but I keep forgetting where I have put it and can never find it when I need it, so I was thinking of buying a spare. I am bewildered by all the choices out there. What should I choose? It is just for occasional DIY repairs and dabbling. I won't be doing any surface mount work or anything that small.

Which width do I need 0.7mm or 1.2mm or doesn't it make much of a difference?

From what I can tell, leaded solder cannot be used if you are selling your products but since I will not be selling anything, would you advise me to buy leaded solder rather than a lead-free alternative? I have googled and there seem to be many sites that don't like lead-free but just as many that do, so I don't know what to think about it.

Flux or no flux seems to be just as controversial.

TIA

[The Nomad]

How big are the 'jobs' component parts?

Lead every time. Lead-free is the work of some nasty person. And the ecological benefits are very marginal. The fact that medical and aeronautical/aerospace are 'allowed' leaded must tell you something!

(Except if plumbing you are 'supposed' to use lead free as it will dissolve in the water and dissolve your brain allegedly ...)

Flux cored if electronics stuff (if pipe-work flux free).

HTH

[Tim Watts]

On Friday 22 February 2013 07:40 The Nomad wrote in uk.d-i-y:

Not just. Autmotive is exempt too.

[Andy Wade]

Alloy 60/40, or 'savbit' if you're still using a copper-tipped iron.

Diameter: 1.2 mm is a good choice for all-round electrical/electronic work, larger if it's for metalwork.

Flux: there's a huge choice available nowadays. Unless you're sensitive to the fumes you won't go too far wrong by sticking to the traditional rosin-based '362' grade. More aggressive fluxes (e.g. acid-cored solder) can be useful on metalwork, but must be washed off after soldering - these are quite unsuitable for electronics work, obviously.

[Andrew Gabriel]

You need thin solder if you are doing small work. Otherwise either works, but thicker is slightly cheaper and may be more convenient.

Correct (with some exceptions - specific products which need to be very reliable, such as life support systems).

I use leaded, because most of my component stock is tinned with leaded. This isn't an issue if you're starting from scratch, as new components are not lead-tinned. I'm also often working on circuits which are all lead solder anyway, where you should use leaded.

I do have some lead-free solder, which gets used when appropriate (very occasionally). It's no different providing your soldering iron is hot enough (and I use a hot iron anyway, 800F). You have to make sure you don't have any lead present (should use a different soldering iron tip, or it must be very well cleaned off after having been used for lead, as small traces of lead does nasty things to lead- free solder), and lead-free eats through the plating on soldering iron bits faster - I think the iron plating is slightly soluable in it, or something like that.

Always with flux for electronics work, as it's too small to apply the flex separately. You only use separate flux when the items being soldered are large, e.g. very large high current electrical work, plumbing, etc.

[Dave Plowman (News)]

0.7mm is much better for small connections and you simply use more of it for large.

Stick to leaded.

[whisky-dave]

Yes I'd stick with thicker 1.2mm 18swg.

I use the thinner with silver content as it';s used puerly for electronics.

and education or so I've been leaded to believe :)

yes you also shouldn;t mix them for relibility issues but I think that's more to do with small electronic parts.

That's not really true, it's more of a pain to use (unleaded) and a good joint looks like a bad joint (dry joint) of leaded solder (i.e not shiney). when using unleaded solder you also need differnt bits as the flux/rosin/whatever is far more corrosive and attacks the bits.

I buy the bits for lead free solder, but still use them for leaded solder.

My range is 230C to 400C (450F-750F). Using an antex 690sd iron. with a 0.5mm to 2.3mm tips.

[Man at B&Q]

Thinner stuff disappears quicker :-) Only realy needed for fine jobs where you need to control the application.

I use nothing but lead free these days. Anyone who says it's difficult to use (in a domestic/hobby setting) is an idiot who has never learned to solder properly.

No controversy, always use flux-cored for electronics asembly.

MBQ

[meow2222]

Whatever youre comfortable with. Thin is easier to use on tiny parts, thick is easier to use for everything else, and cheaper.

Maybe you'll never know what to think until you try both. here have been a lot of complaints in the industry about lead free.

For electronic work, solder should always have flux built into it. I've tried fluxless dipped in flux and its poorer, but usable on large joints. I wouldnt consider it for small work.

Surface mount work is often done with a paste of solder powder in flux.

Never use acid flux (killed spirits) on electronics, traces remaining eat through the thin metal. Some folk also use separate rosin flux at times with electronics, but most don't bother.

I use different irons for leaded and unleaded.

NT

[Dave Plowman (News)]

I do quite a bit of electronic soldering, and quite honestly 1.2mm is rather too thick for anything involving a PCB. And I have four sizes here on a dispenser. ;-) The 1.2mm hardly ever gets used - only for soldering large terminals.

If I could only have one size it would definitely be the smallest one. It can do anything the larger ones do by simply using more.

The smaller size appears to have more flux per cent and tins something better with less solder bulk on it.

[whisky-dave]

Yes I agree, my statement of I'd stick to 1.2mm was aimed at the OP, who wasn;t going to do PCB or fine soldering from what he implied. I personally stick with 0.7mm 22swg.

although I've also used the .45mm 26swg for surface mmount.

Agreed, but I have a selection of all sorts that have been brought and found over the years. We'll be embarking on flow soldering too soon, not sure what we'll be using for that.

That's why I wear those steel toe-capped safety shoes in the lab, one can't be too careful ;-)

[The Natural Philosopher]

It can if its 'instrumentation' :-)

but since I will not be selling anything, would you

if you are using a soldering iron, use flux cored solder.

If you are heat gunning down surface mount stuff, I think you use a separate flux. Not something I have ever done.

[Man at B&Q]

Why, why and why?

No, you use solder paste.

MBQ

[The Natural Philosopher]

mostly because it works better.

the leaded solder solidifies better with far less chance of a cold joint if you move it a bit while its cooling.

The solder is also less brittle when its solid. I think that why critical applications where a joint failure could be life threatening are still allowed to use it.

[charles]

yes - for medical & military applications.

[Tim Watts]

On Friday 22 February 2013 16:54 charles wrote in uk.d-i-y:

And automotive...

[alan]

In a domestic hobby setting leaded solder is much easier to use. Why make life more difficult for yourself.

[John Rumm]

The thinner is better if you want to work on a circuit board - and you have the option of using a longer length to make up for the lack of thickness, whereas the reverse does not always work as well.

Generally, yes. (plumbing excepted)

Go for a good quality flux cored solder. The only time that separate flux really becomes necessary is on surface mount work.

[meow2222]

Yes, upto a point, but having to fast feed an excessive length of thin solder doesnt work well either. I prefer too thick to too thin any day - its only really the tightest stuff where that becomes unworkable.

I've always bought random brands, and never had an inferior product. I know there were poor products out there decades ago, but I've not seen one in a long time.

Its big stuff that needs it, big as in get your 125w iron out. Sm wants it, but is so tiny that you can just use the flux in an extra half millimetre of thin solder wire.

NT

[Fred]

When I find time to dabble, it's on strip board, but most of the time I'm reattaching small wires that have come off the PCBs on children's toys.