I have read some discussions about the lead-free solders on the forum, but could not see what solder type is easier to use for hand soldering (among lead-free ones)?

As an example, I see only two RoHS compliant solder alloy options (e.g. on Mouser at this link).

  • SAC305
  • Sn96.5/Ag3/Cu0.5

Available types:

  • rosin activated
  • water soluble
  • no clean wire
  • spool solder
  • Glow core no-clean

Which properties would you recommend for the one that would melt at a lower temperature and be convenient to use?

I have this lead-free solder that is not pleasant to use because of melting temperature.

  • 4
    \$\begingroup\$ None of the options are particularly enjoyable. Most people I know who try it go back to lead. Prototypes rarely need to be RoHS compliant, so I use lead until manufacturing starts \$\endgroup\$ Commented Jul 4, 2014 at 14:47
  • \$\begingroup\$ You might find this answer useful: electronics.stackexchange.com/questions/103778/… IIRC, I raised the tip temperature by 100°F (56°C). \$\endgroup\$ Commented Jul 4, 2014 at 19:58
  • 2
    \$\begingroup\$ All the lead free solders I have used gave me splitting headaches due to the flux fumes generated at the higher temperatures. Switched back to leaded. The fumes of lead free are likely much worse for your health than the lead of leaded solder for the average hobbiest. \$\endgroup\$ Commented Jul 4, 2014 at 22:10
  • 2
    \$\begingroup\$ I totally agree with John and Scott - I use leaded solder. I did some research (online, if that counts) and the flux used in unleaded solder is, as far as I can see, appears much more unpleasant than the leaded flux. Both are bad for you so I'd always use a fan regardless. I also found unleaded hard enough to work and rework that I don't see why I should toture myself... \$\endgroup\$
    – carveone
    Commented Jul 9, 2014 at 11:12

3 Answers 3


Lead is a magic element that makes solder melt at a lower temperature and protects the tip of your iron against oxidization. Too bad it is a potent neurotoxin.

Most lead-free solders have high melting points. (Bismuth solder paste is lead free and has a lower melting point than leaded solder, but because it is a paste, using it with an iron is not very convenient.)

Without lead, and at higher temperatures, tip oxidization is your #1 problem. That means shutting off your iron immediately when you aren't using it. Don't let it bake. Some fancy lead-free irons have an auto-setback that reduces the tip temperature when it is placed in the cradle.

And stay away from "CLEAN" solder! Water-soluble flux is very aggressive but corrosive! It will eat vias and traces if it is not immediately cleaned off (should be called "MUST CLEAN"). It is only used by industrial processes that include an ultrasonic bath after soldering.

"NO CLEAN" solder is what you want and means the flux is not corrosive and does not need to be cleaned. Yes, the terminology is confusing.

FWIW I like Kester Sn96.5/Ag3/Cu0.5. The fumes are no worse than lead solder.

  • 2
    \$\begingroup\$ Actually, solder fumes from standard temperatures contain extremely low lead concentrations: the vapor pressure of lead at those temps is extremely low. \$\endgroup\$ Commented Jan 30, 2019 at 16:16

"SAC305" and Sn96.5/Ag3/Cu0.5 are the same thing, SAC is just an acronym for Sn/Ag/Cu or Tin/Silver/Copper. The "305" refers to percentages of Ag and Cu (ie 3% and 0.5%). This is really on the only readily available lead free solder in widespread use. SAC105 is also available but offers no real advantage.

All the lead free solders are higher soldering temperature, SAC305 melts at 217C vs SnPb (37% Pb) lead solder at 183.


For hand soldering I prefer wire solder, but paste is possible too. The paste has a shelf life though, after a year it may be too thick to extrude from the syringe.

For fine pitch SMT parts you will want the finest gauge solder.

The key to a good lead free joint is plenty of flux. The fine gauge solder has so little flux in it I always add flux, either liquid from a dropper or "flux pen", or tacky paste which helps hold the parts in place while soldering.

Flux comes in 3 basic types:

  • No Clean: Requires no cleaning or solvents as the residue is inert. Note that this is invariably the least effective kind of flux in my experience. It is also very difficult to clean should you want to.

  • Water Soluble: Very strong and produces very irritating fumes when soldering. This must be washed with water to remove to avoid corroding the assembly. And then the assembly must be dried with something like a hair dryer. I avoid this type for hand soldering.

  • RMA or "Rosin, Mildly Activated" flux. This is the kind I prefer and gives good solder joints w/o noxious fumes. It should be clean off with Isopropyl Alchohol and a brush after.

I would recommend a fan to create a gentle air flow to push the fumes away in any case. Too much air will make it hard to solder due to cooling.

And lastly you need a soldering iron designed to reach the higher lead free temperatures. I always recommend a Metcal with interchangeable tips. They are expensive new, but are built like tanks and older quite functional units can usually be had for less than USD$200 on ebay.


Bit of an old question but:

It's worth looking into SN100C. It's a eutectic alloy of 99% Sn, 0.7% Cu, 0.05% Ni, and less than 0.01% Ge, with a slightly-higher-than-SAC305 melting point of 227°C (compared to 63/37 at 183°C and SAC305 at 217~220°C (non-eutectic)).

It has some of the same problems as other lead-free solders, but it has no silver content (making it cheaper than silver solders), and I've found it easier to work with than SAC305 or pure tin. It flows better and forms good, shiny joints where silver solder doesn't. It seems reasonably good at preventing tip oxidation too, but it's still good to keep some tip tinner on hand.

The main downside is that it's a little harder to find as of 2020, since the patent on it only expired last year and manufacturers other than Nihon Superior (the patent holder) are only just starting to make it. I was able to find it from Chip Quik, who call it CQ100GE, but you may find other sources.

  • \$\begingroup\$ Equivalent names that I found as of 2021 are SN100C, CQ100Ge, Sn100Ni+, SNC100C, NT100Ge and WR-SnC. Of those the first three seem to have the best availability at distributors. \$\endgroup\$
    – BrtH
    Commented Aug 5, 2021 at 16:00
  • \$\begingroup\$ @BrtH SN100C is the name given to it by Nihon Superior; every other manufacturer will likely have their own name for it as, while the patent has expired, I believe the name SN100C is still a trademark or something of Nihon Superior. \$\endgroup\$
    – Hearth
    Commented Aug 6, 2021 at 0:14

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