60/40 vs. 63/37 Solder
in [Basics]
|
From: Joe on 15 Jul 2010 03:54 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. --- Joe
From: John Doe on 15 Jul 2010 04:04 none given.now (Joe) wrote: > Why are there these two very similar solders? Is there any > situation where one is better than the other? Dunno, but... If you do detail work, try water-soluble flux solder. You just wipe off the residue for a sparkling clean circuit. Good luck and have fun.
From: Smitty Two on 15 Jul 2010 07:22 In article <4c3ec127$0$4762$c3e8da3(a)news.astraweb.com>, John Doe <jdoe(a)usenetlove.invalid> wrote: > none given.now (Joe) wrote: > > > Why are there these two very similar solders? Is there any > > situation where one is better than the other? > > Dunno, but... If you do detail work, try water-soluble flux > solder. You just wipe off the residue for a sparkling clean > circuit. > > Good luck and have fun. 60/40 was the standard for many years, until it was learned that 63/37 was more accurately eutectic. 60/40 was kept around as a legacy product since millions of customers worldwide had written the spec into their procedural documentation. But distributors (in my part of the world anyway) stopped stocking much of a 60/40 selection about 20 years ago. As for water soluble flux, it has at least one significant drawback; it is corrosive at room temperature (unlike RMA for example which is only "active" when heated.) Therefore, any flux residue left on the board (or whatever you're soldering) will lead to corrosion. Without full immersion in a sonic tank, it can be difficult or impossible to wash it all away.
From: PeterD on 15 Jul 2010 07:28 On Thu, 15 Jul 2010 00:54:43 -0700, none(a)given.now (Joe) 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. > >--- Joe The advantage is when you need a lower melting temperature. However, the difference is slight. 63/37 also does not have as much of a plastic state when melting.
From: William Sommerwerck on 15 Jul 2010 08:01
As far as I know, no. 63/37 has been "known" to be eutectic for at least 50 years. (I read about it in "Popular Electronics" as a wee babe.) 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. Unless you're Really Cheap, 63/37 is always preferable. It has slightly greater mechanical strength, too, though this is rarely a consideration. J Gordon Holt, who founded "The Stereophile", had his own theories about soldering. Back in the days when people assembled vacuum-tube equipment from kits, he recommended simply poking component leads through the lugs, and soldering them without crimping them. His reasoning was that, if the component ever needed replacement, you wouldn't have to fiddle with uncrimping it. (If you've ever unsoldered old equipment, you know what a tsuris this can be.) The "catch", of course, is that both the lug and the lead have to be very clean, and you're more likely to get a cold or incomplete connection. This is a situation where you would /definitely/ want to use 63/37. While I'm on the subject... I once asked the late Bob Tucker, * who wrote the user manuals for Dynaco, why the soldering instructions were, at one point, obviously in the "wrong" sequence. He explained that Dynaco's "policy" was that, once a lug had three wires in it, it was to be soldered. There was otherwise too-great a chance of it being overlooked and remaining unsoldered, only to cause problems down the line. * Bob, who passed on in the late '80s, was one of the nicest, most-gracious people you could ever hope to meet. He was, perhaps surprisingly, also one of the handsomest men I've ever seen -- by comparison, most actors and fashion models are plain -- but he didn't seem aware of it. |