60/40 vs. 63/37 Solder
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From: David on 16 Jul 2010 10:53 "Jim Yanik" <jyanik(a)abuse.gov> wrote in message news:Xns9DB76443FE679jyaniklocalnetcom(a)216.168.3.44... > "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 The Meijer store here in Illinois has 99% isopropyl. It is normally about $1.25 for a 16 oz. bottle but occasionally they run sales of 2 for 1 at that same price. I stocked up with about a dozen bottles the last time they ran that sale. I avoid the lower % stuff because it is not always diluted with just water but sometimes oils and skin lotions. These are to be avoided for electronics work. David
From: William Sommerwerck on 16 Jul 2010 10:55 > I avoid the lower % stuff because it is not always diluted > with just water but sometimes oils and skin lotions. > These are to be avoided for electronics work. This is usually labelled "rubbing alcohol".
From: GregS on 16 Jul 2010 11:53 In article <i1ovm1$ccb$1(a)news.eternal-september.org>, "William Sommerwerck" <grizzledgeezer(a)comcast.net> wrote: >>>>> 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. I like 63/37 because some stuff I do I like it as low a temp as possible. Deja vu. I worked for BFEC at NASA site, and went to NASA ssoldering school. I would guess 60/40 would be the norm. greg
From: Jeff Liebermann on 16 Jul 2010 11:56 On Thu, 15 Jul 2010 13:06:03 -0700, dplatt(a)radagast.org (Dave Platt) wrote: > >>Why are there these two very similar solders? Is there any situation >>where one is better than the other? >> >>I understand the eutectic nature of 63/37, and I wonder if/when 60/40 >>might ever be better to use. > >My understanding is that 60/40 has somewhat better wetting properties >than 63/37, at least with some contact materials. Some people prefer >it for that reason. > >63/37 makes a sharp transition between liquid state and solid state at >a single, well-defined temperature. 60/40 goes through a transition >between these two states over a significant range of temperature - in >between the fully-solid and fully-liquid states it can have a somewhat >mushy texture. Some people feel that 60/40 brings with it a somewhat >higher risk of creating a "cold" solder joint (inadequate fusion with >the contact surfaces) if the joint is moved or stress while the solder >is dropping through its mushy-state temperature region. True. 60/40 goes through a semi-molten, plastic-like state, while 63/37 goes instantly from liquid to solid. The joint is not mechanically solid in this plastic state. It's not an issue with tiny components, that cool down rather rapidly. However, large components, that retain more heat, can product "cold" solder joints if moved while in the is plastic state. In some cases, this plastic state is desireable. For example, pre-RoHS plumbers solder was 50/50 for both low cost and the ability to remain workable over a wider range of temperatures. <http://www.chemguide.co.uk/physical/phaseeqia/snpb.html> <http://en.wikipedia.org/wiki/Solder> This got my attention: Some alloys, namely of lead and to some degree tin, contain small but significant amounts of radioisotope impurities. The radioisotopes undergoing alpha decay are a concern due to their tendency to cause soft errors. Polonium-210 is especially problematic; lead-210 beta decays to bismuth-210 which then beta decays to polonium-210, an intense emitter of alpha particles. Uranium-238 and thorium-232 are other significant contaminants of lead containing alloys. Oh swell.... something else to worry about. -- Jeff Liebermann jeffl(a)cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558
From: William Sommerwerck on 16 Jul 2010 12:47
> I like 63/37 because some stuff I do I like it as low a temp > as possible. Allmost all my soldering is repairs; cold joints seem more likely when you're fixing something. > Deja vu. I worked for BFEC at NASA site, and went to NASA > soldering school. I would guess 60/40 would be the norm. Probably. I never had to solder, so I never went to school. Which site? When? I worked from 1974 through 1978. |