Recommend lead-free solder!

[Fleet]

Hello SoR,

In all the (often very true, but not be discussed here) fuss about lead-free solder being lousy compared to Pb-solder, it's hard to find some help to choose lead-free solder that's well suited for soldering the 50$-bot controller? What can you recommend, and why? (links and/or parts numbers, please)

Best regards, Fleet

PS: If you really want to help me out, then check if there's some good lead-free solder here: http://elektronik-lavpris.dk/index.php?cPath=6057_6050_6053

[garrettg84]

I use off the shelf radio shack lead free solder. I don't have any 'production' needs and it suits most of what I do just fine. YMMV.

The reason Pb-solder is so nice is that it melts at lower temperatures. I have a pretty good iron (http://www.all-spec.com/products/Soldering_and_Rework|Soldering.Rework_Equipment|SOL-10/WD1002T.html) and I solder at about 760 degrees with my lead free solder. All melts quickly and I'm on and off the joint in a second or two.

[Soeren]

Hi,

In all the (often very true, but not be discussed here) fuss about lead-free solder being lousy compared to Pb-solder, it's hard to find some help to choose lead-free solder that's well suited for soldering the 50$-bot controller?

Only if you don't care to read the treads about it!

What can you recommend, and why? (links and/or parts numbers, please)

Fact is, I cannot recommend any of it really.
And since I have this idea that you're afraid of lead like you're afraid of PVC (sure you're in the right hobby?), you should be aware that the lead free fuss is not for your sake (as a user), since the lead doesn't do anything to you - most of the lead free variants however, contains highly poisonous substances and fluxes, which will have a bad influence on your health.
That said, have it your way, but steer clear of those with Halide and those containing poisonous metals, or your grand children may look funny in a very non-funny way.

PS: If you really want to help me out, then check if there's some good lead-free solder here: http://elektronik-lavpris.dk/index.php?cPath=6057_6050_6053

The least bad of them and the one that should be best for hand soldering seems to be this.
The 0.75 mm is by far the best alround dimension for hand work and the amount of silver makes it close to eutectic (it really should have a bit more, like closer to 4% silver for that, but it's close).
Do read the MDS (especially toxicology and allergy risks) and decide if you really want to use this made-in-Hell poor substitute for good old leaded harmless-to-you solder.

Yes, silver is expensive... Another good reason to stick with lead (even though I prefer both in my solder).

[blackbeard]

it's an unfortunate thing but there are TONS of toxic things in the world of electronics. unless you buy all pb-free components then they may very well have lead tinning! then there's all the acid cores, fluxes and toxic fluids just itching to contribute to your chances of getting cancer. if it's for your own sake then using lead free solder is just a small part of the overall solution. if your doing it because you have children or something then you are best locking the room where you work.

[Soeren]

Hi,

The reason Pb-solder is so nice is that it melts at lower temperatures.

Oh, if a higher temperature was the only difference, nobody would worry at all!

Lead free solder doesn't flow as well, although there are large differences in how well they float.
The metallurgy of the lead free has, in varying degree with the different composites, a large tendency to crack the joints, mostly due to the metals solidifying at slightly different temperatures a characteristic where the different metals sort of separates itself into small "islands".

In a number of years, I expect the industry to have solved these issues, at least to some extent, but the hobbyist shouldn't be part of that experiment, as it takes large amounts of solder to test each, expensive instruments and recorded ways of testing and that's just out of reach of Joe Random.
As an added "bonus", consumer electronics made recently and in the coming years will have a shorter life span (good news for us in this is, that we can just open up and retouch the soldering to get most of them back in order).