why is 63-37 eutectic solder not universally preferred?
- posted
16 years ago
why is 63-37 eutectic solder not universally preferred?
It costs a bit more.
An old buddy of mine, his next door neighbor brother in law used to own an old crapped out 1966 Alfa Romero convertible car.That was back in the
1970s.One afternoon, he was out there trying to patch up the rusted out floor pan of that car with a bar of straight lead.Of course, that didn't work out at all. cuhulinsnipped-for-privacy@webtv.net wrote in news:16430-476307C0-390@storefull-
3258.bay.webtv.net:
pure lead used to be used for filling body ripples and dents,before Bondo and plastic fillers. Lead's wide "plastic" range was well suited for that task.
-- Jim Yanik jyanik at kua.net
Because you can't sell it in the EU if it's got lead in it.
Uh... 63-37 has lead in it.
The 63 is tin, the 37 lead. Traditionally, tin has been more expensive than lead, so eutectic solder cost more than 60-40.
Not true at all. There are plenty of organisations that are still legally allowed to use 60/40..... Schools colleges/military/telecoms/space etc. Plus many more who don't care about lead free....
Plus lead helps prevent the formation of 'tin whiskers'.
-- If there is a no_junk in my address, please REMOVE it before replying! All junk mail senders will be prosecuted to the fullest extent of the law!! http://home.att.net/~andyross
Because sometimes you want mush.
Eutectic is either solid, or liquid.
Formulations off eutectic have a range of mushiness, which can be of use.
And they have higher melting points, which can be of use in multipart assemblies, where you might use 50-50, 60-40 and 63-37 to assemble and solder a series of parts.
-- Cats, coffee, chocolate...vices to live by
Smitty Two wrote in news: snipped-for-privacy@news.phx.highwinds-media.com:
When I worked as a process engineer for Sprague Electric Co, in the early
70's, making capacitors and resistors, we used 95/5 solder, I think it was tin/lead with a small amount of silver, to assemble the capacitors and resistors.One reason for that choice was so that the parts would withstand normal
60/40 soldering when boards were assembled.Like you, I have some doubts about the kind of close control that would be needed to use mixes as close as the ones given.
-- bz 73 de N5BZ k please pardon my infinite ignorance, the set-of-things-I-do-not-know is an infinite set. bz+ser@ch100-5.chem.lsu.edu remove ch100-5 to avoid spam trap
bz wrote in news:Xns9A07DE839DD08WQAHBGMXSZHVspammote@130.39.198.139:
I doubt it can be that accurately done. I use various indium based solders for making small assemblies of optics and electronics when I want to get different melting points, and you need well defined narrow ranges for ech solder, with at least 10 degrees apart between each rangem ideally, because an assembly might easily see several degrees variation unless you're prepared to control the conditions with expensive rigour and to wait a long time for equlibrium to settle each time you change the temperature. Two solders wth overlapping ranges for melting would be useless.
Not true, most if not all UK wholesalers still sell 60/40 leaded solder.
Ron(UK)
...
It's not whether you can melt it, it's how it hardens. Eutectic solder hardens very suddenly. 60/40 solder goes through a fleeting stage of being viscous but not yet completely hard. I'd like to hear more about this, but I'm told some people prefer the "feel" of one vs. the other.
I am indeed trying to discuss the original topic of the thread. The original poster's question interested me, an nobody has responded to it.
I have a roll and a half of a roll of old solder, I bought back in the
1960s/1970s.A few old soldering irons too.Two of them are American Beauty (brand name) soldeing irons and another one is an Ungar with several interchangable tips in a metal box and I have a few old (I like old, old, old stuff) Weller soldering irons.My favorite kind of a soldering (electric) iron I use is an old electric wood burning iron. When you are through using some solder from a roll of solder, use some pliers to squeeze the end of the solder on the roll tight.That keeps the liquid inside of the solder roll from leaking out.I don't like the new solder.If you want lead, buy some made in China toys. cuhulindances_with snipped-for-privacy@yahoo.com wrote in news:a232ec67-c9bd-42ad-99f3- snipped-for-privacy@t1g2000pra.googlegroups.com:
Probably because the gradual solidification makes dry joints less likely. I'm not even sure it it does make them less likely, but I bet it does because you're not relying only on ductility of a solid to maintain good structure during thermal contraction. If the two metals in the alloy don't solidify together, one can flow to fill pores that might form in the other, or between the solder and the parts joined with it.
If by "dry joints" you mean what I was taught as "cold solder" -- where the solder crystallizes and looks like the dull side of a sheet of aluminum foil, then you've got it backwards.
63/37 solder passes from liquid to solid so fast that there's almost no chance for the solder to crystallize (which is usually caused by movement during the cooling phase) and so has _less_ chance of forming cold joints. 63/37 also has a lower melting point than 60/40 which means that theoretically it puts less heat stress on the component being soldered.In practice I don't think the difference in melting points makes much difference, at least for hand soldering, since the iron's tip temperature isn't controlled that tightly. But I can definitely say from personal experience that cold solder joints are much less frequent with 63/37 than 60/40. Not impossible, though.
-- Gordon S. Hlavenka http://www.crashelectronics.com It's bad luck to be superstitious
From my days at Mullard in the early 1960's, I seem to remember that thermostatically controlled irons were not used, there were horrible large things like an ice pick!
Multicore set the standard in the UK for many years and what they suggested/supplied was what industry used. As everything was hand soldered then, it had to be a solder and flux with as wide an operating temperature range as possible.
Peter
-- Peter & Rita Forbes Email: snipped-for-privacy@easynet.co.uk
During my brief stint in England (1977-78) I got some Multicore solder and found it very easy to work with. Is it still available? In the USA?
On 60/40 vs 63/37 solder see:
Kester says that because of the gradual solidification, 60/40 gives thicker coatings when you want to tin things with it. This may or may not be advantageous depending on what you're doing.
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