"Purchasing loves to "shop" for the best price on solder."
Big mistake. Even if the stuff is 63/37 with acceptable metallic
impurities, cheap stuff will inevitably have a lot of dross in it (I
assume you are talking about bars/ingots for wave soldering). Some
expensive stuff will do as well, but that's another story :-( And, guess
what? The more dross there is, the more nuclei there are for more dross
to form, so you will get to unacceptable dross formation much sooner. A
couple of decades or so ago, I sampled 4 or 5 makes of 63/37 bar sold
specifically for wave soldering. The best, in terms of both minimal
dross and correct metal composition, was Alpha Vaculoy. Multicore
Extrusol had almost twice as much dross and was slightly low in tin, but
less metallic impurities. The rest didn't make the grade in any way.
One, of German origin, had about 4 times as much dross, only about 60%
Sn (despite being stamped 63%) and 3 times the other metallic impurities
but was 40% cheaper than Vaculoy. Guess which one sold the most, where I
was? That's right, the cheapest, which was undoubtedly the most
expensive to run, if you were concerned with quality.
As for variations in analyses, this is normal. Not only do you have to
have a good, constant, sampling method, you have to use the same
analytical method to obtain consistent results. There are four or five
methods used currently and each will definitely give different answers
and each will have different tolerances, even assuming perfect
calibration. Even the sampling requires different methods according to
the analytical method (e.g., X-ray diffraction requires a sample of
defined thickness). Some methods are more accurate for the main metals
and less so for impurities and vice versa.
A veritable can of worms.
Brian
Paul Truit wrote:
> I have an issue I'd like to hear from this forum. I have recently had a
> sales call from "solder company B" wanting to sell me solder. When
> asked which solder company I use "solder company A" I am warned about
> the possibility of not receiving virgin grade metals. Suggests that I
> have an analysis performed to verify. I allowed "company B" to perform
> the analysis but I also sent a sample out to "company A" for the same
> test. The results came back not agreeing. One said my solder is fine in
> regard to tin content (62.78%) the other said it was bad (60.8%) The
> skeptic in me doesn't want to believe either of them right now.
>
> Purchasing loves to "shop" for the best price on solder.
>
> Can someone tell me about this virgin grade versus reclaimed solder? Is
> this a marketing idea? What defects would I see from the "inferior" one?
> How do I know if my solder was from "reclaimed" metal? Isn't tin tin
> and lead lead? Is there an unbiased source to send a solder sample to
> so I can really know what is in my solder pot?
> --
> Paul Truit, Mfg. Eng.
> RBB Systems, Inc.
> 4265C E. Lincolnway
> Wooster, OH 44691
> Ph. (330) 567-2906 ext 514
> Fax (330) 263-5324
> Email: [log in to unmask]
>
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