Soldering iron, leave the solder on or not?

Flyback said:

you cleaned it, but may i ask did you wipe it totally & thoroughly clean, so it had no tin whatsoever when placed back hot-in-the-holder?...i beleive you left some tin coverage.?

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Have you never used a soldering iron in your life? It is literally impossible to "wipe" all solder off of the tip of a hot soldering iron. No matter how many times or how hard you wipe it on a sponge or paper towel or whatever, it is physically impossible to completely wipe the tip clean. So of course leave a thin coating of tin on the tip. You don't have a choice.

the linked doc tells you to keep the tip tinned at all times, it wouldnt say this if you never had to bother...many would like to be sure its defintely tinned by just not wiping it thoroughly

To prevent oxidation, keep the tip tinned with a thin coat of solder at all times -- not only during soldering but also when the iron is sitting idle in the holder.

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JimB said:

I am one of those (former) highly senior engineers who always cleaned his tip before putting it away.
In maintenance situations working on older equipment, the tip could get coated with all kinds of unknown gunge and clag. And we don't want that stuff baking away for who knows long before we use the iron again.

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I think it depends on usage..... If unused for long periods of time, then I would tin before putting away... However, my iron is always on.... I buy a packet of tips ( 3 ) and I'm good for years... At £4 a pop... Who cares...

I use mine iron often, and when I do, I always start by wiping it off that brass-thingy (haven't used that wet-sponge for long time now)..

surely the most definitive way to ensure it doesnt oxidise when left hot-in-the-holder is to leavve it blobbed up with solder and dont waste time wiping it at all......and in fact, DO wipe it when you take it out to use it....surely thats the time to wipe it.....i know lots of physics peple will say that the surface stiction of the iron keeps it tinned even when you wipe solder off it, but i am not sure this always applies..so to be sure, i leave it blobbed up to heck.
Though i'm well used to seeing juniors getting "launched" for doing the same thing. -They are accused of disrespecting the tools, etc etc,

Flyback said:

surely the most definitive way to ensure it doesnt oxidise when left hot-in-the-holder is to leavve it blobbed up with solder and dont waste time wiping it at all......and in fact, DO wipe it when you take it out to use it....surely thats the time to wipe it.....i know lots of physics peple will say that the surface stiction of the iron keeps it tinned even when you wipe solder off it, but i am not sure this always applies..so to be sure, i leave it blobbed up to heck.
Though i'm well used to seeing juniors getting "launched" for doing the same thing. -They are accused of disrespecting the tools, etc etc,

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Honestly, I don't think that it makes much of a difference whether you blob it up or just leave a thin coating of tin on the tip of the iron. It might take a little longer to heat up with a larger blob of solder due to the excess thermal mass, but it'll hardly be noticeable. I wipe mine before putting it away after soldering just because it looks better. Functionally I don't think it makes a difference.

i find a lot of tips, when new, go black straight away if you turn the iron on with a new tip and dont tin the tip as its heating up. (im sure you would second this)
This is evidence of oxidation, and encourages me to "take shelter" from this situation by leaving it very visibly blobbed up after use.

I actually worked in a place where they went through a few weeks of constantly buying new tips, turning then on for the first time without tinning them...then they'd go black, then they'd throw them away , and moan at RS that they were sending us duff tips, and order some more, only for the same thing to happen again, and again, and again......if the UK could just for once post a positive Balance of Trades figure then i wouldnt sob so uncontrollably when i see this happening so much, in so many places.

I once saw an intern getting "rocketed", for tinning a new tip when he first switched it on.....the guy was telling him not to be so daft, and that new tips "obviously" never need tinning, because they are "new".

Every new tip I have ever bought from RS comes pre-tinned... The only way they go black is if they are over temperature... If you have a station, then as long as the tip is @ 300~350 degrees it'll stay good for months... The standalone irons that have no temperature settings go black and need sorting... If you are using an iron everyday buy a good one....

Every new tip I have ever bought from RS comes pre-tinned

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You mean the coating, i assume you dont mean somebody has literally tinned it with solder at the factory.

The coating is tin... All new tips must be dipped, well all the ones I buy!! I also have my own tin plating paste to spruce it up if I use my iron too long at high temperature.... ( Or I stupidly plastic weld with it )

The doc kindly attached by canada elk also says how a blackened tip can be brought back to life by kind of sanding it down, presumably with emery cloth.... i am not used to seeing people do this, and i thought that it ran the danger of sanding away the special thin coating that is required on these tips

Flyback said:

The doc kindly attached by canada elk also says how a blackened tip can be brought back to life by kind of sanding it down, presumably with emery cloth.... i am not used to seeing people do this, and i thought that it ran the danger of sanding away the special thin coating that is required on these tips

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I have heard this as a recommendation before as well, and I completely disagree. One should never use an abrasive material on the tip of their iron. I don't think it has as much to do about removing the "special coating" as it does with leaving microscopic pits and fissures like I mentioned before.

Started with an old Weller "gun" type in the late '50s (I think it was 100/140 watts ...!).
The bent up tip is exactly how mine always looked (kept having to straighten it with a pair of needle nose). Used Kester .125 rosin core solder.

The tips (solid copper) came un-tinned and I always tinned them up first thing. Never worried much about cleaning the tip: just shook off excess since I was doing tube type, boat anchor circuits (Allied Radio Knight kit sort of stuff).

But the excess rosin (slightly acidic) would collect (where I stuck the arrow above) and, without fail, that's where the copper would corrode and break. Went through beaucoup tips before I made that connection (no pun intended...). I'd just tension the two halves against each other and keep on solderin'.

15 watt pencil solderer for many years now. ALWAYS wipe off excess solder AND flux on a wet sponge (nothing more abrasive!) after every single use. Same tip in place for over fifteen years.

Thanks, now, weve already confirmed that its not actually possible to totally wipe off all solder on an iron after use......so why bother wiping it off at all?..........why not just wipe it just before you are about to use it, ie just after you remove the iron from its holder....you always have to wipe it then anyway.
I still believe that the more blobbed over the tip is, the more protected it is from oxidation........i mean, as long as you use the right fluxed solder..........though all solder does slightly degrade the iron with its flux, as we've said, you cant totally clean off the solder from an iron anyway...theres always that bit of a film of solder left.

Flyback said:

Thanks, now, weve already confirmed that its not actually possible to totally wipe off all solder on an iron after use......so why bother wiping it off at all?

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Once again, I just prefer the way it looks. Functionally I don't think it makes a difference.

Why do we wash the flux off a circuit board? I have this irrational fear that the gunk on the tip is not good for it. It takes but a second when putting your tip cleaner away to wipe the tip (I like a scrap of old t-shirt dampened.)

And like DerStrom8 , I also like the way it looks.

Flyback said:

You mean the coating, i assume you dont mean somebody has literally tinned it with solder at the factory.

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Yes...

Look at this picture:


Two Oryx tips left and centre and a Weller tip on the right.

The Oryx tips have certainly never been used, and I don't think that I have ever used this Weller tip.
The tips are made from copper and have an iron coating, the Oryx tips are slightly magnetic. I did not bother to test the Weller tip as it has a magnet in it anyway, that is how the temperature control works.

The iron coating is a dull grey colour on the Oryx tips and there is a bright coating at the end of the tip where it was dipped in solder at the factory when it was made.
When using a tip for the first time, I would always melt plenty of solder on to the tip as soon as it got hot enough.
When wiping a tip on a sponge, there is no way that the solder layer is going to be removed completely, it will just stay there a few microns thick.

Some of the very "high end" soldering procedures from organisations such as NASA, say to put a small amount of solder on the tip before putting the iron into its stand. This may offer some advantage with regard to a cleaner tip before the next joint is made, but I suspect that the effect is marginal.

Note that copper is soluble in solder, which is why tips are iron plated.
A bare copper tip will be dissolved away by the solder which it melts. There is a type of solder known as "SaveBit" which contains a small percentage of copper in the nominal 60/40 tin/lead mixture.
It must be nearly 40 years since I last used SaveBit, but it was effective and reduced the wear on the old plain copper soldering tips.

JimB

If you're using a crappy iron with an unplated copper tip, this thread might make some sense. If that's the case, throw it out and get a decent iron that uses plated tips.

Why do we wash the flux off a circuit board? I have this irrational fear that the gunk on the tip is not good for it.

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Yes, some types of solder contain a flux which will degrade the tip....but as we've said throughout this thread.,,,,its not possible to totally remove the solder film from the tip, even by wiping it......so it looks like we're screwed either way, and so are just as well to not bother wiping the tip at all.....

Or is it the case that if we wipe the tip then that will tend to remove the flux, but not the solder, and so in that case, since its the flux thats the bad guy with respect to tip degradation ,then it certainly is worth wiping the tip before putting it in the stand.The weller doc does not elaborate, but just says that the tip should be left tinned at all times.

You should never use acid flux with an electronics soldering iron. This type of flux is intended for plumbing and other applications where the material is thick and can handle some material being removed. Rosin flux is safe for electronics soldering and will not eat away at your tip. Most of it will burn off during use anyway (which is why you may find you need to frequently re-flux the tip). If you apply solder to the tip of your iron with the flux, wipe it, and put it away, then the flux will probably have time to burn off before the iron cools.