Solder - 1.1lb Spool (0.020") Special Blend

Replacement:TOL-10242. We know you can't get enough of the special blend, but we just don't sell the big spools anymore. You can still get the 1/4 pound spool though, which should last you a while. This page is for reference only.

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.

The spool is 1.1lb (500g) and has a 0.020" (0.5mm) diameter.

**Note: **We found these in inventory but we're no longer stocking them. We'll be selling them at a discount for a limited time but when they're gone, they're gone!

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

  • [MSDS]( Indalloy with Fluxcake-301 (CW-301).pdf)


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.

  • Jassper / about 14 years ago / 5

    I agree, sell it in a trial quanity, or better yet, include 8 inches of it with every order. If it is truly the best it will sell itself.

    • Exonerd / about 14 years ago / 2

      Yet another endorsement of smaller quantities. SFE did a wonderful service with the small bobbins of conductive thread for Lilypad stuff, and a similar "sample size" would be awesome. I know we'd all even pay for it :P

    • MattTheGeek / about 14 years ago / 2

      I like that idea. (Or at-least the idea of getting free stuff ;) )
      I trust you guys that this is the best solder out there, but a pound of solder (Who knows how many feet) is overkill for me. a 25 to 75 foot spool would be nice.

  • I'm amazed at the casual disregard some posters have for their own health (and the health and IQ of others).
    I hear that asbestos is a great fire-retardant -- you can make a tablecloth out of it, and then just throw it in the fireplace when you're done, no washing! A nice asbestos tablecloth, and asbestos-insulated wires, should go nicely with leaded solder alloys.

    • Demolishun / about 13 years ago / 1

      Ask yourself this question:
      Why is there an exemption to ROHS for lead in solder used for medical and safety devices?
      Toxic substances need to be used in a responsible manner. With solder it is really a matter of how the product will be used and how well entrapped are the toxic substances. In an alloy such as solder welded to copper traces it is pretty much fixed in place. Even if tossed in a landfill it would be hard to prove the lead is going to go anywhere. I agree recycling of electronic parts is preferable and designs with a throw away life cycle should not use lead.
      Also, note that asbestos does not burn. You can throw it in the fire if you want, but it may cough up particles as it smothers the fire. However, you are free to do whatever you want with your retro textiles. :)

    • Hey man, noone lives forever.
      But seriously, I dont see the big fuss with using leaded solder, at least for the home hobbyist. If I was making 100k units that were all disposable or something, thatd be alot of lead. Id want to keep it out of the landfills.
      But me, tinkering around in my (well venitlated) garage? Washing my hands? Not licking my PCBs? Im willing to take my chances, thanks. If you cant follow those guidelines, then by all means, try this. But please dont insinuate im insensitive or anything like that.
      Also, unleaded solder is TERRIBLE for vehicle applications. It took a 400W soldering gun about a minute to solder some 10ga wires, with leaded solder. Unleaded...well I might still be there. The more common smaller gauges are still a major PITA sometimes.
      I would give this stuff a shot, but not for $50.

  • BB / about 14 years ago / 2

    Ugh, I'm not going to risk my DIY electronics to unleaded solder. I pity those Europeans who have no access to leaded solder, who are forced to use designed-for-obsolescence solder.
    I'm sure this solder is decent, but all lead-free solders require higher heat, are often non-eutectic, and quite frankly have inferior qualities compared to good ol' leaded solder. For my own needs a big roll of Kester Flux "88" has never let me down, and it'll be decades before I ever need to buy more, unless the States fall to the same lead-free solder heresy that the Europeans have fallen for.

  • JerryG / about 14 years ago / 2

    In my experience, all lead-free solders suck compared to 63/37 lead-based solder. Higher melting point, doesn't flow as well, and tends to ball up on a joint.
    With Kester 63/37 going for around $25 for a 1 lb. spool in my area, I think I'll pass on this stuff.

  • Member #79910 / about 14 years ago / 2

    Is it eutectic? If not, I don't want it. Eutectic solders like 63/37 tin/lead make for some of the best joints. Eutectic blends have little or no plastic stage between liquid and solid... they solidify very quickly, making it harder to make cold solder joints by moving the piece as it cools.
    I personally use some Kester 63/37 with a "no clean" flux. I have a big bottle of inorganic, water soluble flux that I usually use along with it. Despite being water soluble it's AMAZING, although it WILL corrode your piece if you don't quickly clean it off.

  • Kevin Vermeer / about 14 years ago / 2

    Does anyone have any comments on using this stuff? I trust you guys, but I'm hesitant to drop $45 on a totally new solder based on your estimation that it's the best in the world. Any other believers out there? I could draw courage from a datasheet, or even just posting melting point/wetting/strength/thermal fatigue/flux characteristics in a comment would be great.
    In my experience, lead free solder melts hotter, and water-soluble flux doesn't work as well. I understand that they're better for the environment, but I'm not making large quantities and don't really care. However, I'm glad to know that you use them.
    A patented Sn96.2/Ag2.5/Cu.8/Sb.5 ratio (wikipedia) gives a 217C melting point, 'Excellent' wetting and thermal fatigue, and a 6000PSI joint strength versus 187C, 'Excellent' wetting and 'Poor' thermal fatigue, and 5600PSI for 63Sn/37Pb.
    Any comments on the effectiveness of your flux as opposed to the RMA on most guys' work benches?

    • Kevin Vermeer / about 13 years ago / 1

      OK, I broke down and got this just before it was discontinued.
      It works great! Easily soldered a 0.5mm pitch QFN. And $45 really isn't bad for 1lb of solder.

  • Larsie / about 13 years ago / 1

    I bought this solder. Seems ok, but I'm getting a grey matte finish on the soldering joints. Not shiny. Am I doing it wrong, or doesn't that matter. I might be using too high temperature (250-300 Celcius). Otherwise it seems fine.

    • DavideV / about 13 years ago / 1

      This page: seems to indicate that a dull finish is normal for lead free solders. If it gets grainy it may be getting too hot.
      I haven't tried this solder, but I find that if I spend too much time on a joint, and the flux "cooks out" of the solder, then it does look a bit grey and "off" looking compared to a really nice one. Maybe if your iron was on the hot side, you would need to work a bit quicker, but 300 C shouldn't be too hot. And remember, heat the work, not the solder. If you are heating both at the same time, you are much more likely to burn up your flux. I'm not a professional, but I when doing PCB's, I heat the pin and the contact around it first, and when it gets hot enough, I just give it a light tap with my (rosin-core, lead containing) solder, and a small amount instantly flows around the hole and pin.
      For the record, I use the old solder for personal projects, especially radio repair. It's a bit taboo to mix solder types in a radio, especially when the old radios contain much more toxic things than lead, and you want to heat these components as little as possible.

  • stuff dude guy / about 14 years ago / 1

    What is the best size to get this in, .5mm, or .79mm?

  • scharkalvin / about 14 years ago / 1

    As far as the use of lead solder goes ...
    AFAIK, it is almost impossible to absorb lead through (unbroken) skin. However not washing your hands after handling lead and then eating is another story. Fumes from soldering mostly contain flux residue, not lead (not that the chemicals in flux can't be harmful). The greatest danger from lead solder is that of disgarded electronics ending up in the landfill and leaching into the ground water. That is the major reason for baning lead solder (and other things made of lead such as fishing weights).

  • Kenta / about 14 years ago / 1

    Any idea when we can see sample sizes of this stuff?

  • chrismurf / about 14 years ago / 1

    Does your $40 analog "SparkFun-branded" solder station have enough oomph to work with this stuff? I'm upgrading my woodburner, and was thinking of getting that iron with this solder and not looking back. Will I regret having a too-weak iron or lead-free solder if I go for that (sparkfun-approved) combo?

    • Pearce / about 14 years ago / 1

      We've tested this and it definitely works, that iron is great for someone looking to solder a decent amount.

  • please!! put together a $.50 sample kit, most people wont take the plunge until they try this stuff

    • We have smaller sizes coming. We won't have $0.50 samples, but we will have a smaller and cheaper quantity which would allow you to test it out. But seriously, it's good stuff.

  • GreenTechGuy / about 14 years ago / 1

    Until I am proven otherwise I think the Kester K100LD is the best lead-free solder ever ! it is cheaper than silver based solders and has the same shine as lead-solders to boot !!
    I would love to hear about the pros and cons of the SAC, K100LD and other lead-free solders.

    • Pearce / about 14 years ago / 1

      Probably the main reason we enjoy this solder so much is because it flows very cleanly and with very little effort. Had I had this solder at my disposal when I was a tech in production, it would have cut down my excess use of flux dramatically.

      • GreenTechGuy / about 14 years ago / 1

        Have you folks given the K100LD a try? I have used this AIM Castin SnAgCu-Sb solder and I think K100LD wets better at a lower price. I do not know about the copper dissolution rates being touted by Kester for their K100LD. The AIM Castin may be better for production runs but for hand soldering the K100LD is great. I use a Metcal 700F tip for both. By the way, I am no way connected to Kester or AIM. I am just a happy customer :)

  • InfraPulse / about 14 years ago / 1

    So, what temperature do you recommend using with this stuff?

    • Pearce / about 14 years ago / 1

      I usually solder around 360-390 fahrenheit

      • Kevin Vermeer / about 13 years ago / 1

        I think you mean Celsius. My Pace iron doesn't go down that low, but 360-390 oC (~700 oF) is right in the upper-middle of the scale. My 63/37 doesn't melt when my iron is set to the lowest end of the scale, which is about 550 oF.
        Gah, why is the HTML 'sup' tag not allowed in comments? Those are supposed to be degrees.

      • stuff dude guy / about 14 years ago / 1

        Really? The US navy standards say that lead solder is to be soldered at 650F and unleaded at 700F. The sparkfun iron doesn't even go as low as 360-390F.

      • InfraPulse / about 14 years ago / 1

        So using 250C (482F) would kill it?

        • Pearce / about 14 years ago / 1

          Possibly, I've never soldered at that temperature before, but at the temperatures mentioned above the solder will flow no problem.

          • Coyote / about 14 years ago / 1

            Lol I use 800F, I wonder how it works at that temp.. I'd like to try it though...

  • johnfrank / about 14 years ago / 1

    ROHS is a pain in my ***! i'm sure having pb free solder, proper tips, flux, etc makes it easier.... but it won't change the fact that every time i have to rework pb free joint, i suddenly want to punch a hippie! i'd try a baby spool or if you happen to stick some in my next order, i'll see what its all about... but until then, i'll keep soldering things 3 times and screaming obscenities at inanimate objects. thanx hippies!

    • Dude, you punch hippies too? Just kidding.
      We are getting samples in 'soon'. You might want to check it out. It's easier to clean up after than most other types (lead-free or leaded) and it flows pretty well. You might want to convert.

  • We are checking on smaller quantities. I like the idea of giving away a small quantity. We just have the big rolls from our first order for our production department.

    • esklar81 / about 14 years ago / 1

      How about taking the "roll your own" approach? ;o}
      By my calculations:
      0.5 mm diameter => ~0.196 mm^2 = 0.00196 cm^2
      The density of Sn is ~7.3 g/cm^3, so
      the linear density of the solder is, approximately:
      (0.00196 cm^2) * (7.3 g/cm^3) = 0.014 gm/cm.
      So, a 500 g spool should be approximately:
      500 g / (0.014 g/cm) ~= 35,000 cm = 350 m
      If you folks cut a roll into 1 m pieces, rolled them gently around a handy object ~ 4 cm in diameter, and put them in little plastic bags and slapped on labels, you could generate samples for about $0.15 apiece. Getting one of those with one's order would be quite pleasing. (If you really want to thrill us, how about a meter of each of the two diameters, which I estimate would cost you $0.25 apiece.)
      If you want to eliminate folks placing trivial orders (1 LED, for example) to get the solder samples, set a minimum order. For example, a $25 minimum would limit the cost of a 2 diameter sample to 1% of the retail price of the order.
      Alternatively, you could provide samples with orders that, by their content (for example, a kit that is to be soldered or a soldering iron), indicate that the purchaser solders.

      • Kevin Vermeer / about 13 years ago / 1

        Instead of $0.15 per meter, they could sell 6m pieces for $5.95...That's a 661% markup. Ouch, guys! These are samples we're asking for, in hopes of buying your $45 spools.
        You should take a cue from this guy's drill/Arduino based solder spooler, and try to reduce that overhead:
        I'd buy 6m for $1.95, more than double your raw material cost.

      • We never plan on doing minimum orders, ever. I like your idea, but we are in the process of ordering smaller quantities and will just stock those. Thanks for the suggestions!

        • esklar81 / about 14 years ago / 1

          Just to clarify:
          I was NOT suggesting that SparkFun set a minimum order size in general; I meant a minimum order size to qualify for the solder samples.

  • GrimFox / about 14 years ago / 1

    Lead absorbance in adults is only 10%. (this is via ingestion not skin contact) This means that you would have to ingest 5.6 grams of lead to pass the threshold of lead poisoning. (100mg/L of blood) In 63/37 tin/lead solder that equates to 15grams of solder, in your mouth. Is lead dangerous? Sure, if you are not careful, washing your hands, avoiding eye/nose/mouth/ear contact, common sense. Be more careful about storage in areas where kids might get their hands on it as their absorbance is much higher 40-60%. But as with all things not meant for kids that's a given. In a landfill lead acid batteries contribute more lead to the environment than do electronics. That's not going to stop the anti-lead groups though and we'll all have to make the switch eventually. Do your own research and make up your own mind.

  • ChuckT2 / about 14 years ago / 1

    I would find other brands more economical from other stores so this is not a bargain for me.

  • GrantE / about 14 years ago / 1

    I would really really love to see this sold in smaller quantities. $47 is a lot for me to spend on solder. Mind you, this would probably be a lifetime supply, but still.
    Sell it in whatever quantity drops the price to $10-20 and I'd definitely buy it.

  • BrianG / about 14 years ago / 1

    Why replace solder with poisonous lead in it with solder with poisonous antimony in it?

    • -MH / about 14 years ago / 2

      Antimony content: 15 hundredths of one percent.
      Lead content: 37 percent.
      Simple numbers.

    • SomeGuy123 / about 13 years ago * / 1

      For the same reason people replace sugar with splenda.
      It's still bad for you, but it's often considered to be, 'not as bad.'

  • This solder rocks! It is very easy to use and hardly need any additional flux. It also seems to clean your tip nicely. I don't know what makes it work so well, cause I'm not here for my brains, I can only speak from experience. I have been working here for a while and I have seen a few too many different kinds of solder. This being the best, in my "professional" opinion. We took rolls of this solder to Makerfair this year because it was so easy to use.

    • ...And its easy to clean. just a little wet brushing and all residue comes off leaving your solder joints clean and shinny.

  • Striker121 / about 14 years ago / 1

    Anyone else find it ironic that on the warning label for a lead-free solder it specifically says that it Contains Lead? Lol xP, and naturally it gives a reference to California.

    • SomeGuy123 / about 13 years ago * / 1

      For anybody who's curious, those labels are a result of California Proposition 65.

    • Applekid / about 14 years ago / 1

      All the metals that compose this solder can contain trace levels of lead, generally at a few ppm (it's really tough to get super-purity grades of these metals).

  • elmer_fud / about 14 years ago / 1

    Any chance you will be be selling it in smaller quantities. I think it would go bad before I could use it all up.

    • NOTgate / about 14 years ago / 1

      Solder goes bad D: what happens when it goes bad, and how long does it take?

      • elmer_fud / about 14 years ago / 1

        I don't know how long it takes to go bad but I find "bad" solder at school on occasion. I have found some with solid flux that doesn't flow or solder that melts really funny. I had some one day that the flux seemed to stay put or something when you touched it to an iron because after it melted it still had a distinct center I wouldn't be surprised if the bad solder I have encountered is 10+ years old.

      • thmjpr / about 14 years ago / 1

        Google tin pest/tin wiskers. Due to the extra additives in this mix, it shouldn't have these problems. But I don't think anyone knows for sure yet.
        The mix is called "Castin" and more info can be found on
        This is their test info, which of course makes it look great:

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