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Sunday, May 13, 2012

Has your solder EXPIRED?

Wow, here's another thing to worry about:  Has your solder expired?  Is it past its "use by" date?

This came up in the discussion of the Heathkit voltmeter being built on the Evil Mad Scientist blog (see our post on this from a few days ago).  One commenter wrote:

If you ever look at a spool of solder-- one made for use in industry --it will have an expiration date. And that date always seems surprisingly soon, to us.
Here in Silicon Valley, we regularly purchase solder (including flux-cored 60/40) that is discounted because it is sold after its stamped expiration date-- sometimes as much as five years past. To us, this is just "a good deal." We've had some spools work better than others, and it would be very hard for us to *prove* that one is "bad" because it's old.

None the less, the solder manufacturers are explicitly clear on the subject.
Kester, one of the most important manufacturers, says "Flux cored solder wire has a limited shelf life determined by the alloy used in the wire. For alloys containing more than 70% lead, the shelf life is two years from date of manufacture. Other alloys have a shelf life of three years from date of manufacture."
Source: http://www.kester.com/Portals/0/Knowledge_Base_Articles/Shelf_Life_Policy.pdf

Alpha, the manufacturer of the solder included with this kit, says of (at least one of their) flux-cored solders, "If >36 months from manufacture, please submit sample to Cookson Electronics Assembly Materials for testing."
Source: http://alphacpmd.com/~/media/Files/CooksonElectronics/TB-RELIACORE15-WRC-USAPE-SM334-9%20%2010-09-28.pdf

 What happens when it expires?  Does the smoke start to smell bad?   Steve Smith -- please help us out here.

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  1. In keeping with Bill's comments about putting some soul into what I build, I regularly use what is left of a roll of solder that I got from a friend (Tony G6HTC) who has been a silent key for the last 26 years, and it still seems to be fine !!

    Nick G8INE

  2. Sad to say I don't solder enough to use it before the expiration date, got to remedy that!!! Dave - KU9L

  3. I didnt know that... Well it seams that I just might have to get some new solder from frys.

  4. I do have one question how can you tell that you have expired solder if the label has been taken off?

  5. A use by date? There might be something in it and perhaps I'm being cynical, but -if nothing else- it certainly sounds like a good way to sell more solder to me.

  6. But you can't just dump all that lead in a landfill where it could enter the water supply. This is hazardous e-Waste!

    Instead send it to Leif's Expired Solder Disposal Service, act now and for a limited introductory period I will accept your expired solder free! You only need to pay the shipping.

  7. Solder Expires? I have old solder where the flux has dried up, but it still seems quite usable - even more so if you add fresh flux first.

  8. I have a pretty old roll (> 20 years). The most noticeable difference is that the surface is heavily oxidized. Instead of being shiny and silver, it appears to be dull and grey or dark grey.

    The old solder still works fine, even with the flux that is in the core. Haven't had a cold joint yet.

  9. I have solder that's 30 years old or more. Still use it, it's fine.


  10. that doesn't make a lot of sense. Does this mean that my solder joints that I've made more than three years ago (with a fresh solder) are now all "expired"?

    73 k3it

  11. Nothing "goes bad" .... but the oxidation on the actual solder may be too excessive for the amount of flux in the core to properly compensate for ... so additional flux may be needed. The expiration is for the product in hand....and rightly so, there may no be enough flux for the oxidation on the solder.

  12. Depends on the solder. I've used 10 year old Kester solder that worked great. I used some expired Radio Shack solder that just smoked and turned black

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