60/40 vs. 63/37 Solder
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From: Jim Yanik on 16 Jul 2010 09:48 "William Sommerwerck" <grizzledgeezer(a)comcast.net> wrote in news:i1ovm1$ccb$1(a)news.eternal-september.org: >>>>> The only reason 60/40 was ever manufactured in the first place is >>>>> that tin is more expensive than lead, so 63/37 solder costs more. > >>>> Cite, please? (and I don't mean a link to commodity prices) > >>> I can only cite "common sense". 63/37 has always been >>> more-expensive than 60/40. > >> Then you can't substantiate your contention that 60/40 was THE >> worldwide standard for tens of years just because it was a few >> pennies cheaper per pound? That is the statement of yours with which >> I take issue. > > I have no objection to your objection. > > However, 60/40 was never, ever, "a few pennies per pound" cheaper than > 63/37. For the last 30 years, the price of eutectic solder has been > sufficiently higher to make one think twice before buying it. The last > time I purchased solder, I decided that a one-pound roll of Kester 44 > would last the rest of my life, and I splurged. (At this point in my > life, my prediction is coming true. I rarely solder any more. If I > drop dead, someone digging through the junk will find a pleasant > surprise. Assuming they know what 63/37 is.) > > I just checked Parts Express, and a 1# roll of Kester 44 60/40 is > $22.23. 63/37 is $26.85. That's a $4.62 difference, almost 21% more -- > hardly "pennies per pound". When I bought the same product some years > back, my memory is that the price was around $7.50 for the 60/40, $9 > for the 63/37. Even that wasn't "pennies per pound". > > I looked at the MCM site for Ersin products. Get this... MCM describes > its house brand of 60/40 solder as "provid[ing] the lowest possible > melting point". > > Businesses almost always try to cut every corner they can. If you > think your solderers -- or soldering machines -- are doing a good job, > you might prefer to buy the less-expensive 60/40. > > When I worked at Bendix Field Engineering, I often walked through the > section where a bunch of women (never men) soldered assemblies, > following NASA standards. I never thought to ask whether they used > 60/40 or 63/37. > > > maybe the price difference is due to "new and improved" rather than any other reason. BTW,63/37 has the lowest melt point of all the tin/lead alloys. 361 deg F -- Jim Yanik jyanik at localnet dot com
From: Jim Yanik on 16 Jul 2010 09:50 "William Sommerwerck" <grizzledgeezer(a)comcast.net> wrote in news:i1p4j1$t6b$1(a)news.eternal-september.org: >> Rosin flux can be removed with 99% isopropyl alcohol >> ($1 a bottle at your corner drug store). > > You won't find 99% for $1. (91%, maybe.) > > > 91% is what CVS sells,I don't recall the price,though. -- Jim Yanik jyanik at localnet dot com
From: William Sommerwerck on 16 Jul 2010 10:11 > Maybe the price difference is due to "new and improved" > rather than any other reason. No, eutectic solder has always been more expensive, and the reason has always been that tin is more-expensive than lead. > 63/37 has the lowest melt point of all tin/lead alloys, 361 F Exactly. That was my point, and MCM's error. I remember the little phase diagram in the Popular Electronics article.
From: William Sommerwerck on 16 Jul 2010 10:13 > 91% is what CVS sells. I don't recall the price, though. Drug stores periodically have sales. You should be able to get a pint bottle of 91% for less than a dollar. No point in the 75% stuff.
From: George Herold on 16 Jul 2010 10:49
On Jul 15, 3:40 pm, zekfr...(a)zekfrivolous.com (GregS) wrote: > In article <7a307a68-f754-413e-8113-4b9d0ce7a...(a)c10g2000yqi.googlegroups..com>, George Herold <ggher...(a)gmail.com> wrote: > > > > > > >On Jul 15, 11:42=A0am, John Larkin > ><jjlar...(a)highNOTlandTHIStechnologyPART.com> wrote: > >> On 15 Jul 2010 08:04:55 GMT, John Doe <j...(a)usenetlove.invalid> wrote: > > >> >none given.now (Joe) wrote: > > >> >> Why are there these two very similar solders? =A0Is there any > >> >> situation where one is better than the other? =A0 > > >> >Dunno, but... If you do detail work, try water-soluble flux > >> >solder. You just wipe off the residue for a sparkling clean > >> >circuit. > > >> And one that makes a great humidity sensor. > > >> John > > >Yeah, My prototype of a board with several high meg resistors (up to 1 > >gig.) was put together by myself with old Kester "44" (rosin flux.) > >Worked great. Production did a few with their favorite water based > >flux... No good! Now I have to convince them to go back to the old > >standard. The new ROHS fluxes seem to be even worse. I measured a > >few meg ohms between pads that had been 'cleaned'.... NOT. > > I had a lot of problems with high Z circuitry. Got under the pads. > Some boards I had to clean/dry 10 times. In the interim, some of the cleaner > I used got into some caps and started their own circuit mess. > > greg- Hide quoted text - > > - Show quoted text - What kind of flux were you using? I want to try some tests, just laying down solder and flux gobs on 0805 SMD pads and measure the resistance. Then cleaning and remeasuring. (I've got a bunch of other 'fires' that I'm putting out so this may be a few days.) George H. |