Solder - 1/4lb Spool (0.020") Special Blend

We don't want to hype this solder TOO much, but this could possibly be the best solder in the world. There, we've said it. This is a special blend made specifically for us and we love it. It all started as a quest to find the best solder to use in our production process and ended up being the best we've tried. The best part is that it's lead free and has a water-soluble flux core.

This package contains 1/4lb of solder and has a diameter of 0.020" (0.5mm).

**Mix: **96.35% Sn (Tin), 3.0% Ag (Silver), 0.5% Cu (Copper), 0.15% Sb (Antimony).

Solder - 1/4lb Spool (0.020") Special Blend Product Help and Resources

Core Skill: Soldering

This skill defines how difficult the soldering is on a particular product. It might be a couple simple solder joints, or require special reflow tools.

1 Soldering

Skill Level: Noob - Some basic soldering is required, but it is limited to a just a few pins, basic through-hole soldering, and couple (if any) polarized components. A basic soldering iron is all you should need.
See all skill levels


Looking for answers to technical questions?

We welcome your comments and suggestions below. However, if you are looking for solutions to technical questions please see our Technical Assistance page.

  • Member #861789 / about 5 years ago / 1

    Got 0.020" and 0.032" spools today from a local supplier. Are they expected to splatter ? They make a sizzling noise and splatter very fine solder when I try soldering with the tip at 250c. I use SN100C in general and it doesn't splatter at all.

    Doesn't leave a shiny finish like leaded solder but that's expected - not super impressed with the splatter though.

    • santaimpersonator / about 5 years ago / 1

      That is probably from the flux core. That usually happens if your soldering iron is too hot. Obviously, performance varies with soldering irons and techniques, but I usually set my iron to 650 - 750 F depending on the tip. I do get a little bubbling/splatter, but it is mostly just the flux and not really any solder.

  • Circuitsoft / about 6 years ago / 1

    I love this solder, but the flux gives my wife an asthma attack. Could another version be made with MG Chemicals 8341 or something similar?

  • adamj537 / about 7 years ago / 1

    What do you guys recommend we set our soldering iron's temperature to when using this? I've been setting mine to 600°F (316°C), but the flux splatters a lot, which is unpleasant. Any useful tips?

  • pstemari / about 13 years ago / 6

    The Sn/Ag/Cu content seems pretty typical, what's up with the antimony? I've seen that once or twice. Are there any toxicity concerns with it in the solder? CDC indicates that it's dangerous even in low levels.

    • lexxmac / about 13 years ago * / 1

      Yeah, I read through these. Scary stuff. I've got some of this solder and I'm probably not going to use it now.
      I sent them an email asking for the MSDS sheets (post them?), however, I bet this, like many things on their site, is sourced from some shady place in asia that is not required to provide safety information.

      Edit: They emailed me and posted it. Props.

  • Member #403026 / about 11 years ago / 4

    "according to the ATSDR and EPA, antimony is ranked below zinc, bismuth, copper, and silver (all of which are constituents of lead-free alloys), as well as lead, in terms of its potential threat to human health."

    "Antimony trioxide, used as a fire retardant, is toxic at .5 mg per cubic meter of air. However, antimony trioxide is not formed during soldering or reclamation processes."

    Quoted from A Study of Antimony in Solder

  • bfesser / about 10 years ago / 2

    Just noticed something on the label; this is RoHS compliant as it contains no peanut butter. (Lead is Pb, not PB!) One tip: brush on some flux before reworking this solder. Great stuff.

  • Member #39159 / about 10 years ago / 2

    This is the best lead-free solder that I have ever used, at any price. (You can pay less and struggle more if you wish.) It is also 0.02", which is much easier to use than the more common 0.03" diameters as it is easier to apply small amounts when necessary. I use a 15 Watt fixed wattage iron and it melts just fine (Hakko Dash 15W). Lower silver content solders require higher wattages and can produce more damage and scorch. The washable flux comes off easily, but does tend to blacken on the iron. It wipes off cleanly. The very low antimony content does not concern me - I don't eat the stuff.

  • Paul R. Potts / about 10 years ago * / 2

    I have done soldering since childhood but have only recently started to experiment with lead-free. It has been frustrating. I've been using a Sn/Cu mix from Radio Shack, and had some issues with the higher melting point, and a tendency to carbonize my tips. I got this in the hopes that it would be easier to use. I am not sure what I'm doing wrong, but it is much worse. The flux in this stuff is extremely acrid (much nastier to breathe at the same temperature) as the Radio Shack mix. It flows poorly and wets poorly, forming very high, peaked "beads" on my PCB solder pads. The frozen joints look much worse than the Radio Shack lead-free: they look like cold joints. Worst of all, the flux carbonizes on my iron tip instantly -- just one bit, and it has crusty black stains on it and its heat conductivity quickly plummets until after just a few joints it is unusable. That's starting after a thorough cleaning, and the black gunk is extremely difficult to get off -- wet sponge won't do it, dry sponge won't do it. I'm really disappointed. I'm experimenting with a temperature-controlled iron at temperatures in the range of about 700-800 F. The Radio Shack lead-free seems to work really well at about 740, allowing me to complete a connection in under ten seconds. This... doesn't. I'm cranking it up, and lifting pads, with the same iron. Am I supposed to need to douse everything with more flux? I haven't had to, working on these kits with other lead-free solders.

    I am planning to get myself a new Hakko soldering station after Christmas, and I'll see if those tips work better, but so far -- really disappointed and can't recommend. What is supposedly "better" about this solder?

    • brandonaaskov / about 10 years ago / 1

      I decided to stick it out and play with some different temps until finding something that didn't scorch so easily. Seems like the 600°F is pretty close to the sweet spot for this, where you can get some decent flow and not burn the stuff.

    • brandonaaskov / about 10 years ago / 1

      I have the same problems with this stuff that you're describing. I have a Hakko soldering iron, and at the default 750°F it just scorches the flux. This makes for some crappy joints, some bad fumes (I'm sure), and some nice black marks on my iron's tip that don't appear to come off.

      And, just like this member above, I'm sticking with the Radio Shack version. Perhaps I'll try playing with some different temperature settings, but in my opinion that should be part of the product description. I am personally very unsatisfied with this solder, or any solder that will burn and ruin my iron tips.

  • markmoran / about 11 years ago / 2

    Does the antimony make it much easier to work with? I'd never heard of it, but the links pstemari posted two years ago make it look like pretty unpleasant stuff. If I wanted dangerous solder, wouldn't it be better just to stay with regular 60/40 leaded solder or the stuff you guys include in all the beginner kits? I've been using that well for nine months and find it very easy to work with, and I don't care about being RoHS compliant since I'm only making things for me, but I do have a one year old daughter, so I'd like to use something safer. Am I better off getting the ChipQuik solder that has the same Tin/SIlver/Copper ratio as this stuff but without the antimony?

    • PointyOintment / about 9 years ago / 1

      According to this comment, the silver and copper are more toxic than the antimony.

    • Member #39159 / about 10 years ago / 1

      Antimony is added, in part, to avoid "tin pest" in high tin content alloys. To see tin pest at work, watch:

  • Yeah this solder works great, with flux. Definitely clean your pcb "thoroughly" after. Using hot water scrub with short/stiff acid brush (to clean solder residue) then same with Isopropyl == 99% using a different acid brush (to clean flux). Wash hands before eating any food as solder and or flux can transfer into mouth causing irritable nausea syndrome convincing your wife that her cooking is as good as her aunts left foot. Take out the trash when your finished. (Timmy face) Ventilation should be required, as simple as soldering next to a window fan blowing out.

  • Stonewall / about 13 years ago / 2

    A word of caution about water soluble flux. If not cleaned off with water (preferably hot) it will leave residue on your PCB that can eat away at the copper and cause trace and component faults. It is even more noticeable on fine pitch SMT components. When I used it in the past we always ran boards through a dishwasher but you can't have non sealed parts on the boards like pots etc.

  • bfesser / about 11 years ago / 1

    I started out soldering with cheap RadioCrack Pb-free solder, which I hated, then switched to 60/40 rosin-core, and from there to Ag-bearing, which I loved. I was skeptical about trying Pb-free again, but this solder is pretty damn good! I cranked the temp up to 800 °F on my Hakko, and it was relatively easy to work with. It doesn't seem to suck through holes as much as the leaded stuff (capillary action), and sometimes doesn't immediately wet the iron tip. With a little practice, however, your joints will turn out fine. The flux-residue cleans off nicely with distilled water and cotton swabs (no propan-2-ol, as others suggest, is necessary), for a beautifully shiny finished project. I would recommend this solder to others. For anyone who is unsure, try it out in the smaller quantity:

  • Nandox7 / about 11 years ago / 1

    Got way more expensive than the last time I got it.. :(

  • R0B0T1CS / about 12 years ago / 1

    How about a solder which is easy to clean but also uses a high resistance flux, so that thorough cleaning is not absolutely critical. It's just not feasible at times. Add to those specs "no clean" and you're making miracles happen :)

  • Member #245108 / about 13 years ago / 1

    yep, great stuff. I have been getting excellent results and I'm no pro

  • boztalay / about 13 years ago / 1

    Just wanted to check in and say that I can definitely vouch for this solder. I use it with the water-wash flux pen, which is a must if you're going to use this solder. I solder it at about 350 Celsius and plenty of the flux. Just gotta clean off your soldering iron frequently, or the flux burns up and leaves some black carbony stuff on the iron. It's easy to clean off, though, so no worries.

  • SPCO / about 13 years ago / 1

    Coming from someone who's worked both with electronics and stained glass, I can honestly say that a eutectic leaded solder is the best to work with. While I haven't tried this specific solder, I have tried about every other lead-free solder and I always go back to leaded - it flows better, wets better and melts more uniformly. So despite a small environmental concern, I will continue to use and appreciate good leaded solder. Plus, I have no plans on throwing out my projects anytime soon and I always vacuum reclaim used solder.

    • aaron357 / about 13 years ago * / 1

      I use a fluxless 96% tin / 4% silver solder and it wets the same as 60/40 Tin/Lead. I prefer not to use flux as it can leave a mess (and clean parts usually solder just fine without it).

      • ZeroVirus / about 11 years ago / 1

        From my training in the Navy as a 2M (Miniature/Microminiature) Tech I can tell you that 60/40 is not what he is talking about. He is talking about 63/37. With Eutetic Solder when it drops 1 degree it goes from liquid to solid. With 60/40 it has what we call a "plastic" stage where it is malleable and can turn into a problem.

  • Paul Jones / about 13 years ago / 1

    I've used this type of solder before from a local supplier and I can confirm that it is indeed the best solder in the world!! Can't wait to get some, the local guys stopped selling it about 4 years ago.

  • Kenta / about 13 years ago / 1

    It's nice to finally see a smaller size of this stuff, more affordable for us starving students. Thanks for the great offering guys! Also, the cool SparkFun logo adds to the street-cred, making it that much more desirable.

Customer Reviews

4 out of 5

Based on 15 ratings:

Currently viewing all customer reviews.

2 of 2 found this helpful:

Not the best solder in the world

I don't know what is up with this solder, but this amazingly expensive solder just doesn't work at all with the equally amazingly expensive Weller WE1010 Soldering Station. It doesn't tin up the tip at all, even at 800ºF it just won't work. It mystifies me how bad this solder is compared to the other bits and pieces of old solder I have laying around.

I guess I can't hold it against this product that it is so thin that it is almost impossible to hold onto (and I have good dexterity), but I wish I had known before I ordered such an expensive roll of solder. It bends too easily, buckles under the slightest pressure and won't melt reliably. $30 of solder down the drain. If SparkFun were a store that I could take it back for a return, I would, but sending it through the mail, shipping costs and all, it just isn't worth the effort.


I'm sorry to hear that you're experiencing difficulties with this solder. I use this for many of my own applications and projects as well as the .032" spool. They work well for me. There are a few things that you can try:

  1. Use a brass sponge and tip cleaner (, to clean the tip of your iron. Many irons can develop an oxidized layer from either dry heating or long exposure to the air. Cleaning the tip thoroughly has helped me in many situations.
  2. Rub or apply compatible flux to the soldering surface to allow the solder to better flow.
  3. Independently measure the soldering iron tip temperature to ensure that the iron is getting to the correct temperature.
  4. Use wider tipped irons to allow a larger surface for heat transfer. I'm a big fan of "horse hoof" tips, The tiny pin tips oxidize too quickly for my liking and give me a lot of trouble receiving solder and transferring heat.

2 of 2 found this helpful:

Great solder, but thinner would be great too!

This is excellent lead free solder, but I wish Sparkfun would also sell a smaller diameter version. When working on small pitch parts, I find it's hard to limit the amount of solder deposited. I'd love 0.010" and 0.015" diameter versions of this solder.

1 of 1 found this helpful:

Best lead free solder anywhere

I highly recommend this solder. It is the easiest melting, best flowing lead free solder that I have ever used. I especially like the 0.020" diameter, which makes flow control much easier. I used to introduce my students to soldering with 60/40 lead and felt bad about starting them out on the wrong environmental "foot". We regularly use this solder now with no more beginner's problems than we had with lead. I have also been able to use a cooler iron with this solder. (I have to be honest - any soldering has beginners' issues. Our students regularly burn the tips of their soldering irons. This solder's flux also scorches, but I'm not sure it is any more prone to this than any other.) Buy it!

1 of 1 found this helpful:

Great lead-free choice

This solder melts easily, but holds a firm grip. Even with mediocre soldeing skills, some of my classmates' cold joints made using this solder have held in mechanical connections. Yet, it is still very workable and flows with ease compared to a 60/40 solder I used to use.


Fantastic solder, I think it's the best I've ever used, the thickness(0.5mm) is perfect and it's so easy to use, it melts and flows easily, highly recommend. I've heard some bad things about lead-free solder, but this one is just AMAZING! I got it right the first time I used it, I think it will be a great option for starters, and for any one actually.

Pretty good solder

I like the small diameter for working on tiny parts that require a lot of precision. It’s great solder as advertised and flows really well. Only reason I’m giving it four stars is that I think it’s kinda expensive for how much solder is on there (pretty close in weight to their lead free 200g spool but like three times as expensive), and also the fumes from this are SMELLY. I mean REALLY bad and I had to finally get a solder fume extractor for my desk after using this solder. I’ve used plenty of flux core lead free solder in my life and this puts off by far the worst fumes.

Makes no skill look good

Just switching to this stuff makes every joint look great :)

As a side benefit, it also seems to be way tougher than standard 60/40. I've had to do some small scale structural soldering, and the joint made with this took about 25% more weight before yielding. This was probably due to the superior wetting that this solder can achieve.

Worst solder ever

I have 35 years of soldering experience, and this is the worst solder I have ever seen. melts poorly, does not easily flow or bond to the pads. I have tested this for an hour now in the temperature range between 300 and 400 degree, and I can not get good flow and bonds. compared it to a standard 99.3/0.7 lead free solder, which gives me good results immediately. I normally love sparkfun products, but this is over-hyped crap.

SparkFun brags about this solder. They should!

This solder heats and flows well, and the flux has a burn temperature more appropriate to the solder's flow temperature. It's thin enough for rapidly soldering the headers onto an MCU board, and thick enough for soldering the lugs of a heavy duty switch. In my one-and-only-ever attempt to mount an SMD component, this solder cleaned up after I botched my first attempt so I could get it right.

Notably Better With Antimony

It's noticeably better then the lead free blends without antimony, but not as good as leaded solder. That being said, I'm quite happy to use this.

0 of 2 found this helpful:

better than most lead-free, but...

... it's still cumbersome to solder with it (for beginners, especially) as it doesn't flow with the same ease as tin-lead alloys.

good product, gets the job done

not sure what else there is to say. flows pretty good for a lead-free solder.