Terrible solder from Hell

[Sigmoid]

Today I had a go at adapting some cheap Chinese panel meter movements to my goals - which mainly meant getting rid of the crappy resistors factory-installed into them...
Now the real weirdness was that the solder used to make these was some kind of ungodly horror that smeared the tip and cut off heat conductance, had a hard time melting, jumped all over the place (I burned my hand with flying solder several times when wiping the tip), refused to go even near the desolder wick (in fact it seemed to actively avoid it), and after I was done, I had to use a good length of solder to wet the tip multiple times in order to clean it of this demonic goo.

I wonder if anyone has an idea what the hell that was. Silver-based solder? Lead free? It was just SO terrible, omfg.

[c4757p]

Lead free. More heat, more flux, better iron. I agree, it's shit.

[benemorius]

Yup, lead free is the devil's own creation.

[Sigmoid]

Thanks for the info... Any tips on working with the stuff if I need to rework something that was built using this crap? How can you desolder it? Is a desolder pump the only solution?
Also, I heard it can kill the tip. How aggressive is it in that regard? Is it something you only need to worry about if you have a roll of leadfree and intend to use it up with your traditional tip, or can a few modifications on lead-free devices hurt the coating?

[SeanB]

Your soldering iron tip will have to be about 50C hotter, you will need some extra flux to get a good joint and these will reduce tip life a little. Preferable to keep a separate tip for leaded and lead free, as mixing them in equal proportions makes a non eutectic solder, which can be weaker than either. Mixing a little of one into the other will do little to either. This solder is a good reason to use a brass wool tip cleaner instead of a wetted sponge. If you want to use solder wick on it just add extra liquid flux to the braid and it will work.

[Rerouter]

When you have old oxidised lead free solder, the only real option is crank up the heat on the iron, 400 odd is what i have used for salt corroded lead free in the past, tin the tip of the iron and rub a little to get heat into the joint, then add some clean fresh solder, the solder in the joint wont actually melt more the oxidized skin will come loose, allowing you to much more easily clean and rework the joint,

[KJDS]

Flux, and a soldering iron capable of delivering heat. There's a reason that Metcal, JBC, Pace and Ersa irons are what is found in factories doing a lot of soldering.

[Sigmoid]

When you have old oxidised lead free solder, the only real option is crank up the heat on the iron, 400 odd is what i have used for salt corroded lead free in the past, tin the tip of the iron and rub a little to get heat into the joint, then add some clean fresh solder, the solder in the joint wont actually melt more the oxidized skin will come loose, allowing you to much more easily clean and rework the joint,

Thanks, that sounds exactly like what I had trouble with. My soldering station is an analog adjustable-temperature Weller, I never had trouble with heat conductance with it.

[eKretz]

I have had pretty good luck with this crap by adding some leaded solder to the mix right off the bat. I take a tip dedicated to desoldering and add a good blob of 60/40 to the lead-free joint right away to dilute it a bit, this seems to bring down the melting point immediately and also makes it easy to remove the whole lot with either a sucker or braid. I never have to run my iron over 350°C using this method.

[sub]

I have had pretty good luck with this crap by adding some leaded solder to the mix right off the bat. I take a tip dedicated to desoldering and add a good blob of 60/40 to the lead-free joint right away to dilute it a bit, this seems to bring down the melting point immediately and also makes it easy to remove the whole lot with either a sucker or braid. I need have to run my iron over 350°C using this method.

I have done this as well.  I find it helps to put a little bit of (leaded) solder onto the tip first to aid heat conduction.  Once the joint has melted, put as much leaded solder onto the joint as it can take, and its melting point will drop enough to allow you to rework it reasonably easily.

[Spunky]

Maybe it's something other than lead free solder causing the problem, bearing in mind every peice of mass market electronics that's ROHS compliant has had lead free solder for years I can't believe anyone here is encountering it for the first time.

There are some waterproof laquers that have funny effects and tend to spit back when heated.

[c4757p]

Many hobbyists simply do not touch mass-market electronics with their soldering iron. Leaded solder is still very common in some places. I find it quite believable.

[Sigmoid]

...especially that I'm getting back into having anything to do with hardware after 15 years. No really, the last time I actually assembled a PCB was in the high school HAM club.