Soldering Woes

[wcndave]

Back in the old days, early 90's, I was fairly decent at soldering.

More recently, I had an old 40w iron with only one tip, and was struggling to do some finer work, and to even for example tin wires with it, as the solder beaded on the top, and was impossible to tin.

I got a 75w soldering station: http://www.expondo.co.uk/stamos-solderi ... apter-6100

However i have the same troubles. Even with 490 deg c, the iron cannot be tinned. It just beads up all over it. further down the top, it's fine.

Trying to solder a small joint, the solder would not melt against the wire before it became too hot to hold. Trying to solder into a PCB board, even with just a few seconds, it was hot enough for another component fell out, however the solder had not melted. It seems that the non-tinned tip is the problem, however try as I might, I cannot tin the tip of the iron.

Does this more recent non-lead solder require some other technique?

Hoping for help!

Dave

 

[morturn]

Have you tried wiping the tip with a damp sponge?

If not sponge, a few layers of damp newspaper will also work.

 

[graduate_owner]

Two things, both pretty obvious.
Is the tip of the iron clean before you try to tin it?
Are you using a lead free type of solder, because I believe lead free has a higher melting point than the old lead/tin type?

K

 

[AndyT]

I'd try filing the tip (while cold) or sanding it with fairly rough paper (80 or 120).
Also, is your new solder flux cored? If not, you'll need a tin of flux.

 

[Racers]

Its your solder, the lead free/low fume stuff is pathetic.
You need some 60/40 tin/lead solder that has decent flux to tin your soldering iron.
I have has the same problem my self 60/40 cures it.

Pete

 

[Eric The Viking]

Also, if you have access to good plumbing flux, such as LaCo brand, that, in conjunction with a wet sponge (cellulose - accept no substitutes!*) will clean the tip well - you must tin it immediately.

Also start with the lowest heat that will melt solder on the tip of the iron, and only turn it up if you're soldering a big joint. Two reasons: it minimises oxidation on the iron's tip, and it stops you damaging components with excessive temperature (note I mean over-temp, NOT excessive heat - a rookie mistake is a lot of solder and not heating enough).

E.

PS: I really like Portasol gas irons (with a catalytic heater, not a flame), for odd jobs - capable of a lot of power putput if needed, and can still be subtle too. They run on butane. I have two of these, which are still going after about 30 years.

*other types of sponge melt plastic onto the iron's tip, which is counter productive!

 

[AndyT]

I used to use a bit of old carpet nailed to a block of wood to wipe the tip. It does need to be wool carpet, not nylon.

 

[MarkDennehy]

It's most likely the lead-free solder. That stuff is rather sub-par. You can solder with it, don't get me wrong, but it doesn't make the job easier. You usually have to douse everything in flux before you even start melting the solder to stop it from pooling at the tip.

It might also be the iron's tip - if it's one of the cheapo chinese knockoffs of the namebrand soldering stations, the tip might not be coming up to temperature. There are thermocouple testers you can get to check the calibration of the iron (and they're not that expensive on ebay); if you don't have one you could use an infrared thermometer to check (I wouldn't use anything you have to touch to the iron though, thermocouples not designed for this will read funny and you wouldn't want to be touching the thing with your hands if you're not sure of the electrical isolation of your iron's tip. If it does turn out that the tip's not heating right, and you have a clone of the big name stations, you can probably get tips for very little on fleabay.

But it's most likely the solder. Just buy some of the older leaded solder (in a nice thin gauge, the thinner the better) and use that.

 

[NazNomad]

As above, the 'user friendly' solder is {censored expletive}. Get some nice 60/40 flux cored solder.

Also, grab yourself one of these pan scourers. Perfect for tip-cleaning.

 

[Sheffield Tony]

Even a decent Weller iron tip is hard to tin if it has oxidised. One of those little tins with a solid blend of solder powder and flux is good here, as is the bit cleaner made of brass swarf in a tin (or probably the pan scourer as above). Filing carries the danger fo removing the iron plating, exposing the copper which will then slowly dissolve in the solder.

Lead free solder is useable, but is not all created equal. There are a couple of common types, 99C, and a more expensive type 96SC containing some silver sold as having a low melting point - it is still not as low as Sn/Pb solder, but most importantly it is a eutectic alloy, which makes dry joints from movement whilst cooling less common.

The other factor is the flux. The no clean / low fume fluxes don't do a lot, and if the parts you are soldering have been exposed to air for months you'll struggle. More active fluxes suit hand soldering better. I have some solder with flux described as "X39" that requires new, very clean parts and quite some skill to use. The other, labelled "Krystal 505" is far easier, nearly as easy as leaded solder.

 

[wcndave]

Thanks for all the tips so far (pun not intended).

I had thought / hoped, that the Stamos station was a decent product, as it's in the "premium" section, and seemed to have good reviews.
http://www.expondo.co.uk/stamos-soldering-soldering-station-with-integrated-mains-adapter-6100

The lead free solder I have is this one from Mudder, which has rosin core, and some silver in it.

I make things with the kids, and to be honest, I would like to avoid lead if I can, even though it seems universally accepted that the lead stuff is easier to work with.

So it seems first port of call will be some solder flux, and if that doesn't help enough, then some "re-tipping" product like this one from MG chemicals

Thanks again, I'll have to wait until I visit the UK in May to pick this up, and I'll see how I get on.

Take care you helpful people!

Dave

 

[Sheffield Tony]

Who the heck are Mudder ? Ahh, "SOUNDASIA (CHINA) TECHNOLOGY CO., LIMITED"

I love the warning on this picture from the Amazon site. Like really, I have always sought out genuine "Mudder" products and would be shocked to be offered a fake.

I usually prefer Multicore (Loctite).

 

[MarkDennehy]

Um, dave, you can't ingest the lead in the solder just from soldering from it. It doesn't evapourate. So unless you physically eat the wire...

Now the fumes from the flux, that's a whole other cloud of carcinogens, but just have a small fan pointed at the joint and work in a well ventilated area.
Honestly, third degree burns to fingers are the biggest risk with soldering around kids.

 

[wcndave]

Um, dave, you can't ingest the lead in the solder just from soldering from it. It doesn't evapourate. So unless you physically eat the wire...

Now the fumes from the flux, that's a whole other cloud of carcinogens, but just have a small fan pointed at the joint and work in a well ventilated area.
Honestly, third degree burns to fingers are the biggest risk with soldering around kids.

Yes, i wasn't thinking of the fumes, just it gets on fingers, bad generally for environment, you become more aware of these things when you have kids etc...

 

[MarkDennehy]

No, lead's a thing (20-odd years of target shooting teaches you a lot about particulate lead) and I have a five-year-old myself so I get the kids angle, but it's just not a real risk. The burns, on the other hand, are what I'd be 100% focussed on if soldering with him because irons don't look hot...

 

[wcndave]

My youngest picked up a length of 30mm diameter rebar which I had just cut with an angle grinder, so I think that message is fresh ;-)