60/40 vs. 63/37 Solder
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From: David Eather on 16 Jul 2010 22:02 On 16/07/2010 7:35 AM, Jim Yanik wrote: > "William Sommerwerck"<grizzledgeezer(a)comcast.net> wrote in > news:i1nqh7$7qt$1(a)news.eternal-september.org: > >>> Because it is a eutectic mixture, 63/37 does not have "much >>> of a plastic state". This means it is more [sic] sensitive to >>> movement in the joint while the solder is cooling -- if the >>> connections are unstable it forms more [sic] dry joints. >> >> I don't what you meant to say, but what you did say is backwards. >> Eutectic solder is less likely to produce a dry or crystallized joint. >> >> >> > > I agree; > the eutectic joint solidifies faster and thus less likely to move while the > solder is still "plastic". > > When the joint moves while in the plastic stage it is still electrically connected - when the joint moves with a eutectic mixture it cracks - the joint is very weak when still close to the liquid stage. With the non eutectic mixture the crystals of tin provide strength while the solid is cooling. I might not have explained it very well, but I assure you, with total honesty, that the reason 60/40 was popular was the better reliability for point to point soldering and the reason 63/37 is now taking its place is that point to point has all but disappeared and the eutectic mixture gives slightly lower thermal stress. Either that, or you believe or antecedents were morons, who while they knew about the eutectic mixture, were too stupid to use i,t or too clumsy to mix it, or they thought a few dollars extra per ton of solder was too much to pay for the good stuff.
From: Jeff Liebermann on 17 Jul 2010 01:18 On Fri, 16 Jul 2010 20:14:45 -0400, "Michael A. Terrell" <mike.terrell(a)earthlink.net> wrote: >Jeff Liebermann wrote: >> I have some rolls of solder around the shop that are not well labeled >> or identified. Rather than risk leaving corrosive flux on a board, I >> prefer to clean most everything. > I just tossed solder like that into my solder pot. Right. Great idea. I did that once and regretted it. I tossed most of a 1 lb roll of Ersin 362 (62/38) rosin core solder into the wire lead tinning solder pot. The roll had gotten splattered with acid and was leaking flux. The result was a large cloud of noxious smog, as all the rosin simultaneously went up in smoke. You've seen the smoke produced during soldering. Now multiply that by a few thousand times. If it had set off the smoke alarm, I would have really been in trouble. I don't know the correct way to recycle and remelt old solder. Whatever it is, should probably be done outdoors. -- # Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060 # 831-336-2558 # http://802.11junk.com jeffl(a)cruzio.com # http://www.LearnByDestroying.com AE6KS
From: Jasen Betts on 17 Jul 2010 09:00 On 2010-07-16, Jeff Liebermann <jeffl(a)cruzio.com> wrote: > On Thu, 15 Jul 2010 13:06:03 -0700, dplatt(a)radagast.org (Dave Platt) > wrote: > >> ><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. sounds like bullshit, alpha particles aren't energetic enough to get even 1/10 of the way through the encapsulation on a RAM chip. fraction of the --- news://freenews.netfront.net/ - complaints: news(a)netfront.net ---
From: William Sommerwerck on 17 Jul 2010 09:28 >> <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. > sounds like bullshit, alpha particles aren't energetic enough to get > even 1/10 of the way through the encapsulation on a RAM chip. Correct. The original writer was probably confused by the fact that the materials ceramic ICs are made of can contain radioactive materials that can cause errors.
From: krw on 17 Jul 2010 11:04
On Sat, 17 Jul 2010 06:28:08 -0700, "William Sommerwerck" <grizzledgeezer(a)comcast.net> wrote: >>> <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. > >> sounds like bullshit, alpha particles aren't energetic enough to get >> even 1/10 of the way through the encapsulation on a RAM chip. > >Correct. The original writer was probably confused by the fact that the >materials ceramic ICs are made of can contain radioactive materials that can >cause errors. Happened in plastic too. Intel once helped the problem along by using Kr instead of Ar, IIRC, in a hermaticity test. Battleship steel has a lot of uses, too, since it was forged before the first atmospheric tests. |