Lead free solder

[JackOfDiamonds]

I normally insist on eutectic lead-tin solder for electronics work. It has the lowest melting point, freezes quickly, and is proven reliable. So far, I have successfully ignored the existence of lead-free solders. But with things being as they are, I might have to use them one day. Is there a particular formula of lead free solder that is the best for delicate electronics work? Are there any tricks to working with them (special tips, fluxes, etc)?

 

[no704]

Bismuth has a pretty low melting point and is a good substitute for lead.

 

[htmdude57]

I'm not the expert on this, but I think leaded solder is still best for electronics. I remember hearing of non lead solder growing "whiskers"? That causes shorts or opens. But this might only be a problem in high frequency circuits?

 

[manac]

If you don’t have to be RoSH compliant you use leaded solder.

 

[mark-NJ]

If you don’t have to be RoSH compliant you use leaded solder.

This....100%

If you are required by business / commercial requirements to use this stuff, so be it. But if this is for your personal use, just stick with lead. And, yes, whiskers is a real & serious concern.

Frankly, you (OP) already nailed the reason: eutectic. Non-lead solders aren't (no matter what is claimed), so the dissimilar metals solidify at different temperatures, making a resultant joint will never be as homogeneous as it would if you had used a eutectic.

Lead, for the win.

 

[BukitCase]

"Frankly, you (OP) already nailed the reason: eutectic."

Yup, Sn63 FOREVER (at least for me; I'm 77 and probably have enough to last til I'm 177, or they "pat me in the face with a shovel", whichever comes first) ... Steve

 

[tool_scrounge]

If you need lead free solder, this is the best I have found. Flows almost as well as lead based. I need to try it with an adjustable temperature Soldering iron to see if a little hotter will cause it to flow even better.

 

[jessesandy]

No-clean flux paste is your friend.

 

[PCustoms]

If you don’t have to be RoSH compliant you use leaded solder.

If you can't spell RoHS do you even need to worry about lead/lead free?

Everything I touch at work is lead free

I'd have to check the roll in the shop. I bought it at RadioShack, so it's a little old....

 

[jmarkwolf]

I'm not the expert on this, but I think leaded solder is still best for electronics. I remember hearing of non lead solder growing "whiskers"? That causes shorts or opens. But this might only be a problem in high frequency circuits?

I don't know if lead-free solder behaves that way, but I know that solder with water soluble flux will definately grow such whiskers, unless you wash it immediately after soldering. The good news is that you can wash it with soap and water.

 

[MBfreak]

The whiskers are a real problem in electronics that is tightly built. Like 64 pin CPUs 14x 14 mm footprint.
Was a major problem in power system advanced protection terminals 2005-2010 where I worked. Solved by ultrasonic baths as last step in production prior to testing live.
The whiskers were also a major factor in european made transistors up until appr 1970. They used tinned wires even inside the sealed can. Whiskers grew and destroyed the transistor.

Ola